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Objective  This objective is to investigate the contents and stoichiometric characteristics of soil organic C, total N and total P in Torreya grandis stands of different ages, so as to provide basic data for the management and protection of T. grandis.  Method  T. grandis of four different ages (0−100, 100−300, 300−500 and ＞500 a) were selected from Zhuji National Forest Park of T. grandis‘Merrilli’ in Zhejiang Province. Soil samples were collected from different soil layers (0−20, 20−40, 40−60 cm) to analyze the content and stoichiometric characteristics of soil C, N, and P in T. grandis stands of different ages.  Result  (1) The contents of soil organic C and total N at four ages were 10.90−24.22 and 1.22−2.22 g·kg−1 respectively, which increased first and then decreased with forest age, but without significant differences. The contents of soil total P ranged from 0.24 to 0.80 g·kg−1, which decreased first and then increased with forest age, but the differences were not significant(P＞0.05). (2) The average values of soil C∶N and N∶P at four ages were 8.59−10.89 and 3.06−6.16 respectively, which increased first and then decreased with forest age, but the differences were not significant(P＞0.05). The soil C∶P ratio was 31.54−63.72 at different forest ages, which showed a trend of decreasing first and then increasing with age, and the C∶P ratio of some forest ages had significant differences(P＜0.05). (3) There was a significant positive correlation between soil C, N, and P contents at different forest ages, and extremely significant positive correlation between C and N (P＜0.01). There was a significant negative correlation between P and C∶P ratio, P and N∶P ratio, and an extremely significant positive correlation between C∶P ratio and N∶P ratio(P＜0.01).  Conclusion  The growth of T. grandis is mainly limited by soil P. Therefore, reasonable addition of P fertilization can be considered to improve soil fertility and nutrient cycling between plant and soil. [Ch, 4 tab. 34 ref.]
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Objective  The objective is to analyze soil fertility index and soil fertility quality in typical relocation sites in Shanghai, and to explore the soil fertility quality characteristics of the relocated land in villages and industrial enterprises in the city, so as to provide basis for the use of the relocated soil in landscaping.  Method  The 20 typical relocation sites of urban villages and 16 relocation sites of industrial enterprises in Shanghai were selected, and 7 soil fertility indexes including pH, electrical conductivity(EC), organic matter, hydrolytic nitrogen, available phosphorus, available potassium and bulk density were selected as fertility evaluation indexes. The modified Nemoro method was used to comprehensively evaluate the quality of soil fertility in the relocation sites.   Result  The soil in the relocation site was alkaline, with suitable EC, relatively low contents of organic matter and hydrolytic nitrogen, rich contents of available phosphorus and available potassium, and high soil bulk density. The average comprehensive index of soil fertility in Shanghai was only 0.86. The comprehensive index of soil fertility in the relocation sites of urban villages was significantly higher than that in the relocation sites of industrial enterprises (P＜0.05).   Conclusion  The soil fertility in the relocation sites of Shanghai is relatively poor, 59.3% of which belong to “poor” grade and 40.7% belong to “general” grade. The soil fertility of urban villages is better than that of industrial enterprises. Before the relocated land is used for urban landscaping, soil fertility quality should be improved by technical means to meet the requirements of planting. [Ch, 5 fig. 2 tab. 23 ref.]
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Objective  This study is aimed to understand whether there is a conservation gap of epiphyllous liverworts in the in-situ conservation of China.  Method  A systematic survey of epiphyllous liverworts in Baishanzu National Park and its surrounding habitats was carried out in Qingyuan County, Zhejiang Province. The diversity, distribution, species composition and similarity in and out of the reserve were analyzed and compared.  Result  (1)A total of 25 species of epiphyllous liverworts belonging to 11 genera and 4 families were recorded, including Lejeuneaceae (21 species), Radulaceae (2 species), Metzgeriaceae (1 species) and Frullaniaceae (1 species). The dominant family in the area was Lejeuneaceae and the dominant genus was Cololejeunea. Cololejeunea longifolia and Leptolejeunea subacuta were common species in this area. (2)Among the 25 species of epiphyllous liverworts in 11 genera and 4 families, 14 species belonging to 9 genera and 4 families were found in the park, and 14 species belonging to 7 genera and 2 families were found out of the park. However, the Jaccard similarity coefficients of families, genera and species in and out of the park were 0.50, 0.45 and 0.12, respectively, indicating that the species composition of the two regions was quite different. (3)Compared with the historical data of Baishanzu National Park, there were 6 species newly recorded in this survey, of which 3 species were only distributed outside the park, including Cheilolejeunea chenii, a species with great protection value.  Conclusion  There is a conservation gap in the in-situ conservation of epiphyllous liverworts in Qingyuan County, Zhejiang Province. Therefore, research on the conservation gap of epiphyllous liverworts in other regions of China should be carried out as soon as possible. [Ch, 1 tab. 28 ref.]
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Objective  With the features of the nutrient and enzyme activity of the soil aggregates in the rocky desertification area carefully investigated, this study is aimed to provide a theoretical basis for the soil improvement and vegetation recovery.  Method  With four kinds of soils with different degrees of rocky desertification (potential, mild, moderate and severe rocky desertification) in the Central Yunnan Plateau as the research objects, an analysis was conducted of the distribution characteristics of 3 aggregates (the particle sizes were ＜0.25, 0.25−2.00, ＞2.00 mm respectively), the activity of 4 hydrolytic enzymes (amylase, urease, β-glucoside, acid phosphatase) and the content characteristics of 3 nutrients (organic carbon, total nitrogen, total phosphorus) in the aggregates.  Result  (1)The proportion of aggregates in soil with different degrees of rocky desertification increased with the increase of particle size, from high to low: particle size was ＞2.00 mm (51.31%), particle size 0.25−2.00 mm (36.53%), particle size ＜0.25 mm (12.04%). (2) The geometric mean of soil urease, β-glucoside enzyme, acid phosphatase, soil enzyme activity and organic carbon and total nitrogen content of aggregates with different particle sizes all decreased with the increase of aggregate size. The contribution rate of different particle size aggregates to organic carbon, total nitrogen, total phosphorus and enzyme activity is the highest when particle size was ＞2.00 mm, which was followed by the particle size of 0.25−2.00 mm and the particle size of ＜0.25 mm in a successive pattern. (3) The mean amylase activity of aggregates with different degrees of stony desertification was 5.70 mg·g−1·h−1, and the change trend for stony desertification soil was potential ＞ mild ＞ severe ＞ moderate whereas the change trend of organic carbon, total nitrogen, urease and β-glucosidase activity for stony desertification soil was severe ＞ mild ＞ potential ＞moderate. The particle size of aggregates and the degree of rocky desertification had significant effects on soil organic carbon, total nitrogen and enzyme activity (P＜0.05), but the interaction of particle size and degree of rocky desertification had no significant effect on soil nutrient and enzyme activity (P＞0.05).  Conclusion  In karst rocky desertification areas, soil aggregates with larger particle sizes are dominant in soil composition and have a relatively higher contribution rate to soil nutrient and enzyme activity, while soil aggregates with smaller particle sizes are more conducive to the accumulation of soil nutrients and enzyme activity, with higher corresponding contents as well. [Ch, 2 fig. 6 tab. 48 ref.]
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Objective  Ranalisma rostratum, a critically endangered plant species, is included in the national level Ⅰ key protection plants. Many breeding bases have been established in China in recent years, and the population of R. rostratum has been effectively increased. This study aims to explore the nutritional composition and acute oral toxicity of R. rostratum for its better protection and utilization.  Method  The 4 batches of samples from 3 regression plots in Lishui City were selected, and weighed before and after drying. The biomass ratio and dry-to-fresh ratio of each vegetative organ were calculated. The main nutrients and elements (including fat, N, P, K, Ca, Mg, Fe, Mn, Zn)in stems, leaves and roots, as well as the acute oral toxicity of stems and leaves in Mus musculus were determined.  Result  (1) The dry-to-fresh ratio of the plant was 0.17−0.19, indicating that the water content of the whole plant was high. (2) The average contents of 8 nutrient elements from high to low were N, K, Fe, Ca, P, Mg, Mn and Zn. The coefficient of variation of Fe content among samples and tissues was the largest, followed by P and Mg. (3) There was a significant difference in fat content among the 4 samples (P＜0.05). There were no significant differences in the other 7 elements except Zn among the 4 samples. There were no significant differences in fat content between stem, leaf and root, but a significant difference in Na, P, K and Ca between the stem, leaf and root (P＜0.05). (4) There was a significant(P＜0.05) or extremely significant(P＜0.01) positive correlation among Na, K and Ca, and the 3 elements had significant or extremely significant negative correlation with P, while P had significant positive correlation with Mg. (5) The stem leaf suspended sample liquid was prepared for the acute oral toxicity test, which showed that the oral LD50 of male and female mice was greater than 7.5 g·kg−1 body weight.  Conclusion  The mass fraction of Mg, Fe and P in R. rostratum was unstable, while other elements were stable. The distribution of Na, P, K and Ca in the stem, leaf and root of R. rostratum was significantly different. The acute oral toxicity test of stem and leaf in M. musculus showed that it was practically non-toxic. [Ch, 1 fig. 5 tab. 28 ref.]
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Objective  This study aims to analyze the variation of pollution load in the inlet and outlet sections of the Yangtze River in Three Gorges Reservoir(TGR) area and its relationship with the water level of TGR.  Method  Based on the data of ammonia nitrogen (NH3-N) and potassium permanganate index (CODMn) and water flow in TGR area from 2013 to 2018 at the inlet section (Zhutuo, Chongqing) and the outlet section (Nanjinguan, Yichang, Hubei) of the main stream of the Yangtze River, the pollution load and its relationship with the water level of TGR were analyzed through density distribution curve and Mann-kendall trend method.  Result  (1)The pollution load of NH3-N and CODMn in the inlet section was significantly higher than that of the outlet section, and the pollution load of the inlet and outlet sections was highly correlated (P＜0.01). The pollution in TGR area mainly came from the inlet section and tributaries along the way. With the clarification of the reservoir, pollutants decreased along the way. (2) The pollution load at the inlet and outlet sections was negatively correlated with the fluctuation of water level of TGR(P＜0.01). (3) Mann-Kendall trend analysis showed that the annual load of NH3-N at the inlet section and that of CODMn at the outlet section increased significantly (P＜0.01).  Conclusion  The pollution load is the largest when TGR is at low water level, and is the smallest when at high water level. When the water level is low, the reservoir has less water storage and the water clarifying effect decreases. When the water level is high, the reservoir has a large water storage capacity and a stable water environment, which helps to dilute pollutants. Water pollution control in TGR area and upstream should not be ignored. [Ch, 6 fig. 6 tab. 33 ref.]
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Objective  As an ecological network covering the city, green infrastructure (GI) network plays an important role in mitigating the heat island effect. The purpose of this study is to explore the construction method and reasonable planning and layout of GI, as well as effective measures to improve the urban thermal environment.   Method  The main urban area of Nanjing City in Jiangsu Province was taken as the research object. Based on the morphological spatial pattern analysis (MSPA), the “source” patches with high connectivity and significant cooling effect were selected. The landscape pattern index reflecting the landscape pattern and the surface cooling rate reflecting the surface coverage characteristics were superposed to construct the resistance surface. Then, the minimum cost path method was used to generate corridors.   Result  1) 507 core patches with high cooling rate were identified, and 25 patches were selected as “source” patches based on landscape connectivity analysis. 2) 20 corridors were identified by the minimum cost path method. Together with the “source” patches, the urban GI network was constructed to mitigate the heat island effect. 3) The network was optimized based on Green Space System Planning of Nanjing, and the overall spatial structure of “three rings, six belts and multiple lines” was proposed.  Conclusion  The comprehensive application of various methods makes it more reasonable to construct a GI network to mitigate the heat island effect, and provides a new research approach for building a GI network and improving urban living environment.[Ch, 5 fig. 6 tab. 27 ref.]
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As one of the key processes controlling global carbon storage, carbon cycle in coastal wetland is a process significantly affected by nitrogen input due to the inshore water eutrophication. Given the fact that nitrogen input affects the carbon cycle of coastal wetland in a rather complex way, carbon cycle model has been selected as an effective method to clarify the process with the ultimate purpose to evaluate the carbon storage function of coastal wetland under the global climate change. With an review conducted of the migration and transformation of carbon components in coastal wetlands at different interfaces of atmosphere, vegetation, water and soil and a summary made of the regulations of the response of carbon cycle on nitrogen, it was found that carbon storage and flux is affected by multiple factors. Also, on this basis, carbon cycle models with carbon, nitrogen and water related modules were introduced along with the efforts made to promote their adaptability to wetlands and their application on wetlands, which shall provide reference for the employment of the model in the description of the carbon exchange in coastal wetland under the influence of nitrogen input. Finally, it was concluded that, to further develop the model, closer attention should be focused on the tidal process with nitrogen input and the promotion of model simulation accuracy. [Ch, 1 fig. 1 tab. 126 ref.]
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Objective  This study aims to clarify the structure and diversity characteristics of insect community of Cerasus humilis orchards in different regions of Ningxia, so as to develop effective pest control strategies.  Method  The insect community of C. humilis in three different regions of Ningxia was investigated using trap trapping method from May to September in 2019.  Result  A total of 4743 insect specimens belonging to 10 orders, 46 families and 101 species were obtained. The dominant species were Grapholitha molesta, Serica orientalis, Nysius ericae, Lygus pratensis, Monolepta hieroglyphica, Lagria rufipennis, Hippodamia variegate, Chrysopa formosa, Cataglyphis aenescens and Deraeocoris punctulatus. The descending order of diversity index, evenness index and richness index of insect community of C. humilis orchards was Houmo, Yuquanying, and Shijijuanzi. The concentration probability index from high to low was Shijijuanzi, Yuquanying and Houmo. Similarity analysis showed that the insect community structure in Yuquanying and Shijijuanzi C. humilis orchards was moderately similar in August(0.60). The correlation analysis between pests and natural enemies showed that there was a significant positive correlation between G. molesta and H. variegata (P＜0.05). There existed a very significant positive correlation between N. ericae and H. variegata (P＜0.01), a positive correlation between L. rufipennis and C. aenescens (P＜0.05), and a significant positive correlation between M. hieroglyphica and C. formosa (P＜0.01).  Conclusion  Compared with orchards in Yuquanying and Shijijuanzi, the C. humilis orchard in Houmo has highest stability of insect community. [Ch, 2 fig. 5 tab. 25 ref.]
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Objective  This study, with an investigation of the precise spatial distribution of suitability of Pinus tabulaeformis, a main afforestation tree species in the upper reaches of Baiyangdian Daqing River Basin, is aimed to enhance its guiding role in the construction of water conservation forest and improve the forest water conservation capacity in the basin.   Method  Based on the principles of plant ecology and plant geography, with 190 sample siets data obtained from field survey, and the 24 geographical environment variables (elevation, slope, slope, meteorology, rock type, soil type, etc.) examined, an analysis was conducted of the meteorological factors using multiple linear regression Kriging interpolation (MLRK).   Result  The model of the suitability prediction of P. tabulaeformis reached a very accurate level (ROC=0.869). The accumulated temperature, the annual maximum daily precipitation, elevation and the standard deviation of annual temperature were the main geographical environment variables of the suitability of the P. tabulaeformis. The high suitable area of P. tabulaeformis enjoyed better spatial distribution of suitability in areas like Lingqiu County, Laiyuan County, Laishui County, Yi County, Fangshan District among other counties and cities.  Conclusion  The suitable conditions of P. tabulaeformis in Baiyangdian Daqing River Basin are as follows: the accumulated temperature staying at 2 800−3 800 ℃, the altitude remaining 500−1 200 m, the average annual maximum daily precipitation being 70−110 mm whereas the average annual standard deviation of temperature kept at 0.31−0.42 ℃. And it can be seen that with such conditions P. tabulaeformis forest can grow well and develop better. [Ch, 8 fig. 2 tab. 30 ref.]
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Objective  With an exploration of the relationship between the character changing patterns of mother shoots of seed-bearing shoots and the seed-bearing capacity of initial seed bearers in Torreya grandis ‘Merrillii’, this study is aimed to provide theoretical and technical rationale for the control of shooting, the culture of mother shoots of seed-bearing shoots, and the promotion of seed yield.   Method  With the T. grandis ‘Merrillii’ trees located in Jinyuan village of Lin’an district, Hangzhou city of Zhejiang Province selected as the subjects, an analysis was conducted of the characteristics of mother shoots of seed-bearing shoots either among trees of various levels of vigor or among different layers of a crown, the distribution of mother shoots of seed-bearing shoots in terms of shoot length and thickness, and the relationship between the content of mineral elements in shoots and leaves and seed-bearing parameters.  Result  The mother shoots of seed-bearing shoots from moderately vigorous trees were the thickest and significantly longer than those from the trees of weak vigor (P＜0.05). Trees of various levels of vigor were significantly different in the percentage of mixed buds and seed-setting rate (P＜0.05), with the percentage of mixed buds and seed-setting rate of weak trees being higher than those of vigorous trees. The mother shoots of seed-bearing shoots in the upper layer of the crown were the thickest and longest while those in the lower layer of the crown were the thinnest and shortest (P＜0.05). The proportion of mixed buds and seed-setting rate were significantly different among layers of the crown (P＜0.05) and varied with the vigor of trees, with the seed-setting rate being the highest in the lower layer of the crown of the moderately vigorous and weak trees. The mother shoots with a thickness of 1.91−2.50 mm and a length of 5.51−8.70 cm took up the highest percentage in new seeds and swollen seeds while the seed-setting rate was significantly negatively correlated with the length of the mother shoot (P＜0.01). In terms of mineral nutrition, the nitrogen content in the shoots and leaves was significantly different among trees of various levels of vigor (P＜0.05), with the percentage of nitrogen in the shoots and leaves sampled in June from the trees of moderate vigor being the highest whereas the Ca content was significantly positively correlated with the length of mother shoots, but significantly negatively correlated with the seed-setting rate (P＜0.05).  Conclusion  In the process of production, the cultivation of moderately growing trees with a proper control over the length of mother shoots and the tree height would be conducive to the increase in seed setting rate and mixed bud proportion. On the other hand, it is of great significance to retain the mother shoots with a thickness of 1.91−3.10 mm and a length of 5.51−11.90 cm to achieve the promotion of seed-setting rate and yield. Also, calcium fertilizer plays an important role in promoting seed growth and improving the seed-setting rate in T. grandis ‘Merrillii’. [Ch, 3 fig. 8 tab. 21 ref.]
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Objective  This study aims to explore the effects of partial replacement of chemical fertilizer with organic fertilizer in the production of Solanum melongena.  Method  Taking chemical fertilizer as control (ck), 50% substitution of base nitrogen fertilizer with organic fertilizer (T1) and 100% substitution of base nitrogen fertilizer with organic fertilizer (T2) were set up as two treatments. The effects of different treatments on S.melongena yield, quality and soil fertility were studied in open field.  Result  Compared with ck, soil pH, soil available potassium, organic matter, microbial biomass carbon and nitrogen content increased significantly in both treatments (P＜0.05). The fruit weight and fruit number per plant increased significantly (P＜0.05), which led to the increase in yield by 13.8%−22.3%, and the yield of T1 was highest, which was 70099.5 kg·hm−2. The anthocyanin mass fraction of S.melongena pericarp increased significantly in both treatments(P＜0.05), and thus deepened the fruit color. The mass fraction of magnesium and sulfur in fruits increased significantly (P＜0.05), and that of soluble sugars, soluble protein and vitamin C and the molar concentration of amino acid increased in varying degrees, and the comprehensive effect of T1 was better.  Conclusion  Replacing 50% of the base fertilizer with organic fertilizer can effectively improve S. melongena yield, quality and soil fertility. [Ch, 9 tab. 40 ref.]
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Crocus sativus is a perennial herb with medicinal values such as promoting blood circulation and removing stasis, cooling blood and detoxification, anti-cancer and anti-oxidation. Due to vegetative propagation and successive cropping obstacle, the disease of C. sativus is aggravated day by day. And the corm rot disease caused by the fungus is the most common, which causes a sharp decline in C. sativus output, and seriously affects its industrial development. To conquer fungal disease is one of the effective ways to improve its yield and quality. In this study, the research progress on isolation and identification of soil fungal diseases, endophytic fungi and biocontrol bacteria of C. sativus is reviewed, and research prospect is analyzed. The follow-up research can be carried out from three directions. First, based on modern metagenome sequencing technology, the pathogen and antagonistic bacteria of the corm rot of C. sativus should be studied. Second, based on synthetic biology and fermentation engineering methods, heterologous and efficient biosynthesis of effective substances in C. sativus should be realized. The third is to create a new germplasm for detoxification of C. sativus to provide reliable and high quality provenance for production. This study can provide a reference for research on prevention and control of fungal diseases and the development and utilization of biological fertilizer. [Ch, 3 tab. 89 ref.]
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Objective  The aim of this study is to reveal the mechanism by which overexpression of RAY1 gene (CYC2-like genes) in Senecio vulgaris (Asteraceae) causes ray florets to broaden in varying degrees, and to further explore the underlying causes.  Method  SvRAY1 gene was cloned and analyzed by bioinformatics, qRT-PCR, construction of overexpression vector, SEM(scanning electron microscopy), and morphological observation and statistics of transgenic plants.  Result  qRT-PCR reaction showed that SvRAY1 gene was mainly expressed in ray florets and disc florets, with the highest expression level in the third and fourth stages of ray floret. Morphological observation showed that the ray floret of SvRAY1 overexpression plant was significantly shorter and wider than the wild type. The epidermal cells on the ventral side of the ray florets were observed by SEM and it was found that the width of the line was significantly wider than that of the wild type. The cells at the distal end were tightly arranged, small and divided vigorously. Cell division along the central axis was more vigorous than that of the wild type and the shape of cells changed from curved to smooth.  Conclusion  During the development of S. vulgaris, SvRAY1 gene may promote cell division, and change the morphology and arrangement of ray florets cells in varying degrees, resulting in the widening of the ray floret. [Ch, 6 fig. 2 tab. 28 ref.]
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Objective  This study is aimed to explore the remediation potential of Vetiveria zizanioides on prometryn polluted water.  Method  The characteristics of absorption and removal of prometryn by V. zizanioides with different initial concentrations (1.0, 5.0, 10.0, 15.0 mg·L−1)were studied by hydroponic simulation experiment in greenhouse.  Result  With the same cultivation time, the increase of initial prometryn concentration brought about a significant increase of prometryn concentration (P＜0.05) in the shoots and roots of V. zizanioides, which reached the maximum on the 5th day, and then demonstrated a fluctuating decline. The extension of cultivation time led to a significant decrease in prometryn concentration in water (P＜0.05). Compared with the control without V. zizanioides, the degradation half-life of prometryn in the treatment group with V. zizanioides was shortened by 14.80−19.78 days, and the removal rate was increased by 22.52%−55.57%. The concentration of prometryn in water had a significant negative correlation with the transfer coefficient of V. zizanioides (P＜0.01), no significant correlation with relative removal rate (P＞0.05), but a significant positive correlation with the cultivation time (P＜0.01).  Conclusion  The planting of V. zizanioides can promote the degradation rate and removal rate of prometryn, therefore, V. zizanioides can be used as a pioneer plant in the remediation of prometryn polluted water. [Ch, 2 fig. 4 tab. 31 ref.]
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Objective  The objective of this study is to scientifically and rationally arrange the forest health care base, realize the effective connection between supply and demand, and promote the orderly development of the forest health care industry.  Method  A total of 134 forest health care brand resources in Zhejiang Province were selected as the research objects, including China Forest Health Care Base, China Forest Oxygen Bar, Zhejiang Forest Health Care Base, and Zhejiang Forest Oxygen Bar. By using the nearest neighbor index, geographical concentration index, imbalance index, kernel density analysis, buffer analysis and Pearson correlation analysis, this paper explored the spatial distribution characteristics of forest health care brand resources in Zhejiang Province and the natural, social and human factors affecting their spatial distribution.  Result  The spatial distribution of forest health care brand resources in Zhejiang Province was agglomerated as a whole, and the agglomeration trend was obvious. At the municipal level, Huzhou, Lishui, Taizhou and Wenzhou were homogeneous, while Hangzhou, Quzhou, Jinhua and Shaoxing were agglomerative. The distribution of forest health care brand resources in different cities was not balanced. According to the number of health care bases owned by different cities, they could be divided into four echelons with great differences. Kernel density analysis showed that there were differences in the distribution of forest health care brand resources in different regions, which could be divided into large core area dominated by Anji of Huzhou City, sub-core area dominated by Changxing of Huzhou City, Tonglu of Hangzhou City and Longquan of Lishui City, and small core area dominated by Jiangshan of Quzhou City, Yiwu of Jinhua City and Xinchang of Shaoxing City. The factors affecting the spatial distribution characteristics of forest health care brand resources were topography, forest coverage rate, water system, socio-economic foundation, traffic accessibility, and central city correlation.  Conclusion  Due to the comprehensive influence of natural and human factors, the brand resources of forest health care in Zhejiang Province are unevenly distributed among cities, and there are great differences in the development process of forest health care industry. Topography, forest coverage rate and water system affect the landscape base and ecological environment in the development and construction of forest health care resources and industry. Socio-economic foundation, traffic accessibility and the degree of correlation with the central city are related to its economic support, market potential and accessibility. In the future development of forest health care industry in this province, it is necessary to further combine policy support, market investigation, reasonable planning and resource integration to achieve the goals of global layout, integration promotion, and standardized management. [Ch, 5 fig. 1 tab. 23 ref.]
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Objective  With an investigation of the effects of expansion and eradication of Phyllostachys edulis (moso bamboo) on soil greenhouse gas emission flux and soil physical and chemical properties in Canninghamia lanceolata (Chinese fir) forest, this paper is aimed to provide theoretical basis for the scientific management of moso bamboo expansion.  Method  Short-term in-situ monitoring was carried out of the soil greenhouse gas flux in pure moso bamboo forest (BF), Chinese fir released forest upon the eradication of moso bamboo from the Chinese fir forest mixed with moso bamboo (RF), moso bamboo and Chinese fir mixed forest (MF), and pure Chinese fir forest (CF) using a static chamber gas chromatography method.  Result  The expansion and eradication of moso bamboo increased the soil CO2 emission flux, which were 827.55, 485.09, 374.33 and 300.44 mg·m−2·h−1 for BF, RF, MF and CF respectively whereas the soil N2O emission flux were 120.86, 98.03, 82.89 and 70.23 µg·m−2·h−1, and the soil CH4 absorption flux were 155.38, 145.77, 135.26 and 119.62 µg·m−2·h−1. The soil temperature decreases from MF (19.77 ℃) to RF (18.72 ℃), BF (18.49 ℃) and CF (18.32 ℃) while the soil moisture content decreases from RF (27.32%) to CF (23.04%), BF (18.67%) and MF (16.36%). In these four different stands, the soil CO2 and N2O emission fluxes and CH4 absorption fluxes were significantly positively correlated with soil temperature and moisture content (P＜0.01) with consistent dynamic changes and had a positive correlation with soil inorganic nitrogen (\begin{document}${\rm{NH}}^{+}_{4}\text{-}{\rm{N}}$\end{document}, \begin{document}${\rm{NO}}^{-}_{3}\text{-}{\rm{N}}$\end{document}) but a negative correlation with soil microbial biomass carbon (MBC).  Conclusion  The expansion and eradication of moso bamboo resulted in the increase of soil greenhouse gas emission flux in Chinese fir forest, which had a negative impact on the regional atmospheric environment. On the other hand, the soil temperature and soil water content were the main driving factors for the three kinds of greenhouse gas emissions, and could lead to the differences in greenhouse gas emissions among the four stands. [Ch, 5 tab. 50 ref.]
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Objective  This study is aimed to examine the effects of AC electric field and soil moisture on the remediation efficiency of cadmium (Cd) contaminated soil via the mixed planting of Salix discolor and Sedum alfredii.  Method  With a soil pot experiment, an investigation is conducted of the effects of 2 soil water treatments (moist, keeping 60% of the soil field capacity, and high water content, equivalent to paddy field condition, flooding) combined with 2 AC electric field gradients (0, 0.5 V·cm−1) on soil Cd availability and plant growth of S. discolor and S. alfredii.  Result  The application of 0.5 V·cm−1 AC electric field significantly increased soil available Cd concentration [by 16.13% (P＜0.05)], and promoted the absorption and accumulation of Cd in S. discolor and S. afredii, the soil available Cd and Cd accumulation in leaves of S. discolor and the above-ground parts of S. afredii were significantly higher (by 12.61% and 22.50% respectively) than those of the control. The integrated application of high moisture and electric field contributed to the increase of soil pH, alkali-hydrolysable nitrogen concentration and the proportion of residual cadmium by 6.47%, 12.09% and 22.89% (P＜0.05) compared with those of the control. This integrated application reduced the accumulation of Cd in S. discolor and S. afredii, the accumulation of Cd in leaves of S. discolor and the above-ground parts of S. afredii were lower than that of the control by 95.60% (P＜0.05) and 18.02% respectively.  Conclusion  Under moist condition, the AC electric field was beneficial to the phytoremediation of Cd contaminated soil via the mixed planting of S. discolor and S. afredii. And the Cd accumulated in the above-ground parts of S. discolor and S. afredii was 1.13−1.93 times of that achieved with other treatments. [Ch, 4 tab. 40 ref.]
[Abstract](36) [HTML](10) [PDF](11)
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Objective  The purpose of this research is to screen the optimal specific substrate for roof greening by taking perlite as matrix aggregate, aquasorb (A), biosurfactant (B) and slow-release fertilizer as additives, combined with plant growth indexes.  Method  Based on the analysis of effects of aquasorb [0(A0), 0.5(A0.5), 1.0(A1.0) g·kg−1] and 2% biosurfactant [0(B0), 100(B100), 200(B200) mL·kg−1] on physicochemical properties of perlite under the condition of slow-release fertilizer (30 g·kg−1), two groups of high scoring substrates were chosen by matrix methods for cultivation experiment, and the growth indexes of Caryopteris clandonensis ‘Worcester Gold’ and Iris lactea were analyzed by membership function to determine the optimal substrate.  Result  The aquasorb and biosurfactant had significant effects on the physicochemical properties of the substrates and plant growth indicators of the cultivated plants (P＜0.05). Compared with the control (aquasorb 0 g·kg−1 and 2% biosurfactant 0 mL·kg−1), the bulk density of A1.0B200(aquasorb 1.0 g·kg−1 and 2% biosurfactant 200 mL·kg−1) decreased by 17.11%, capillary porosity and field capacity increased by 10.82% and 55.55%, the mass fraction of total nitrogen, available phosphorus and rapidly available potassium increased by 14.78%, 44.36% and 25.28%, respectively. The plant height, root length, shoot and root fresh weight of A1.0B200 (aquasorb 1.0 g·kg−1, 2% biosurfactant 200 mL·kg−1) were significantly higher than those of the control, and the comprehensive evaluation coefficient of membership function was the highest.  Conclusion  Aquasorb and biosurfactant can improve the water-gas ratio of perlite substrate and improve the ability of fertilizer supply and conservation. Compared with A1.0B100, A1.0B200 is superior. [Ch, 2 fig. 5 tab. 39 ref.]
[Abstract](37) [HTML](4) [PDF](11)
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Objective  Quercus wutaishanica is the main tree species in Liupan Mountains. This study aims to analyze the spatial distribution pattern and correlation of Q. wutaishanica population in Liupan Mountains, so as to understand the growth and development status and population development process of Q. wutaishanica community in this area.  Method  Based on 12 pure forest plots of Q. wutaishanica in Liupan Mountains, the population structure and dynamics of Q. wutaishanica were studied by static life table, diameter class structure, survival coefficient, mortality rate, disappearance rate and survival analysis. Point pattern was used to analyze the spatial pattern and spatial correlation of Q. wutaishanica population in Liupan Mountain area.  Result  (1) The distribution of diameter class structure of Q. wutaishanica in the sample plots was close to the inverted J type, with good renewal status and stable structure. (2) The survival curve of Q. wutaishanica population was close to the deevey-Ⅱcurve. (3) The population of Q. wutaishanica was stable in the early and middle stages and declined in the late stage. (4) The young and middle age individuals of Q. wutaishanica showed aggregation distribution in small scale, which changed from aggregation distribution to random distribution with the increase of scale. Individuals of near maturity tended to distribute evenly on small scale and randomly on large scale.  Conclusion  The tree population of Q. wutaishanica in Liupan Mountains is relatively stable and in good regeneration condition. The young and middle age individuals of Q. wutaishanica show aggregation distribution in small scale, and the correlation between middle age and near mature individuals is not obvious in large scale, independent of each other. In order to keep the structure of Q. wutaishanica forest stable, human regulation should be strengthened to ensure the stable environmental conditions for population regeneration of Q. wutaishanica forest. [Ch, 8 fig. 2 tab. 24 ref.]
[Abstract](62) [HTML](7) [PDF](10)
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Soil organic matter (SOM), an important component of ecosystems, plays an important role in the biogeochemical cycling of soil nutrients. However, it is difficult to analyze SOM chemistry due to its complexity and diversity resulting from microbial and physicochemical transformations of organic residues from plants, microorganisms and animals. Pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) is a fast and reproducible technique to obtain qualitative and quantitative analysis of SOM chemistry, in which has been commonly used in recent years. This paper summarized the components and sources of SOM, accordingly, reviewed the literature which study on chemical composition of SOM with Py-GC/MS technology. The basic theoretical studies of SOM chemistry with Py-GC/MS technology mainly focus on: the chemical composition of SOM and precursor substances from which it is derived, the analysis of specific SOM chemical components, SOM responses to climate change and land use change, and the effects of SOM chemistry on soil processes and functions. The application of Py-GC/MS technology on SOM chemistry included: evaluating the stability of SOM, investigating the cycling of soil nutrition and the succession process of ecosystem. This study showed that: (1) There are some differences in SOM chemical composition among different ecosystems, because the accumulation of compounds from different plants and the mechanisms related to the chemical composition of initial litter can directly influenced the chemical composition of SOM; (2) The SOM chemical composition is closely related to the external environmental conditions and is the result of the comprehensive influence of several factors. For instance, climate is the most important factor that influenced the content and dynamic of SOM by affecting the distribution of vegetation, photosynthetic production and soil microbial activity. Besides, nitrogen deposition, land use change, wildfire and tillage pattern also can influence the contents and qualities of SOM. Overall, it is important to investigate the SOM-related ecological process and the mechanism of SOM response to climate change and human activities, from the perspective of the essence of SOM (chemical composition and structure) based on Py-GC/MS technology. [Ch, 1 fig. 107 ref.]
[Abstract](56) [HTML](13) [PDF](12)
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Objective  This research aims to explore the heterosis of ornamental pepper and the genetic law of ornamental traits, to promote the cultivation of new varieties of ornamental pepper and the retention of excellent traits.  Method  The oval leaf inbred line (P15) of cluster pepper(Capsicum annuum ‘Salsa XP Red’) and the lanceolate leaf inbred line (P6) of single pepper(C. annuum ‘Salsa Deep Orange’) were used as parents, an orthogonal combination P6×P15 and an inverse combination P15×P6 were configured, and F2 population was constructed to explore the inheritance of fruit bearing pattern, leaf shape and plant type of ornamental pepper.  Result  There were significant differences between P6 and P15 in leaf size, plant height and number of lateral branches (P＜0.05). All F1 combinations of cross ornamental pepper showed high heterosis in plant height, plant width and leaf shape. In F2 population of reciprocal cross, the descending order of agronomic characters with the largest variance was leaf length, fruit number per plant, petiole length, plant width and plant height, and there was a significant correlation between plant type and leaf type traits (P＜0.01). The Chi-square test showed that in the results of the segregation ratio of quality traits in the F2 generations of reciprocal crosses, the fruit cluster traits were inherited in a single gene recessively for solitary traits and limited growth versus infinite growth. The developmental plant type versus the erect plant type and the lanceolate leaf versus the oval leaf were both controlled by two genes, and had recessive epistasis.  Conclusion  There are significant differences between ornamental pepper hybrid parents and F1 generation in 5 traits, such as the number of fruit per plant and the number of branching grades. Among them, the coefficient of variation of plant type is the smallest, the coefficient of variation of fruit weight and fruit number per plant is larger, and the difference of leaf length and fruit number per plant is the most significant. The analysis of the inheritance law of the important traits of ornamental pepper reveals that the fruiting bearing pattern of clusters versus solitary and limited branch versus infinite branch are recessive genetic traits controlled by single gene.[Ch, 2 fig. 8 tab. 22 ref.]
[Abstract](46) [HTML](7) [PDF](10)
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Object  It is expected to provide decision-making basis for the promotion of soil testing and formula fertilization technology.  Method  With 1706 family plantations selected as the subjects, this paper, after an investigation of the influence of contract farming on the adoption of soil testing and formula fertilization technology on family farms by means of Probit and propensity score matching (PSM), is aimed to provide decision-making basis for the promotion of such environmentally friendly technologies.  Result  The participation of family farms in contract farming has a prominent and effective influence on the adoption of soil testing and formula fertilization technology with an influence coefficient of 0.621. The average treatment effect is about 0.19 and the adoption of such environmentally friendly technologies is also significantly subject to elements like farmers’ participation in soil and fertilizer cultivation technology training, the duration of large-scale agricultural operations, farmers’ experience, farms’ daily records of income and expenditure and farms' intention for future land expansion.  Conclusion  Contract farming is a vital factor affecting the adoption of soil testing and formula fertilization technology by family farms, therefore, efforts are called from the government to further accelerate the establishment of a sound participation mechanism of contract farming and support family farms in the promotion of their resource endowment. [Ch, 2 fig. 3 tab. 18 ref.]
[Abstract](55) [HTML](9) [PDF](9)
Abstract:
Objective  With an investigation of the structural changes of the endophytic bacterialflora of pine stems, pine needles and pine roots, this study is aimed to fully explore the endophytic bacterial resources of Pinus massoniana.  Method  DGGE and high-throughput sequencing technology was employed in the exploration of the structural changes of endophyticbacterial flora of three-year-old P. massoniana trees upon the infection of Bursaphelenchus xylophilus disease.  Result  (1) There was a significant diversity in the endophytic bacterial community structure in different parts of P. massoniana trees with the diversity decreasing from the pine stem to pine needles and to the root system. (2) There was significant increase in parts of the bacterial genera in pine stems after 15 days of infection, whereas there were no symptoms shown on the surface of the seedlings. (3) Of the 442 genera of endophytic bacteria detected in P. massoniana that fall into 35 phyla, 49 classes, 110 order and 210 families, the relative abundance of Methylobacterium, Sphingomonas, Hymenobacter, Pantoea, Sphingomonas and Curtobacterium in pine stems and pine needles varies greatly throughout the infection process.  Conclusion  The effect of the infection of B. xylophilus disease on the structure of the endophytic bacterial flora varies from none to pretty significant to extremely significant in roots, pine needles and pine stems respectively. And some endophytic bacteria may have potential biocontrol effects on B. xylophilus disease, which is conducive to the excavation of later biocontrol strains. In addition, real-time monitoring of changes in the bacterial community structure of pine stems during the peak period of infection is helpful to the early diagnosis of B. xylophilus disease. [Ch, 5 fig. 1 tab. 25 ref.]
[Abstract](65) [HTML](16) [PDF](3)
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Objective  To promote regional agricultural development, this study is aimed to conduct an investigation of the temporal and spatial distribution and change trend of farmland fragmentation, an important factor that affects the agricultural production efficiency and large-scale management in China.  Method  With Jiaxing City of Zhejiang Province selected as the research area where the comprehensive index of farmland fragmentation of 7 county-level units in Jiaxing City from 2009 to 2018 was calculated, this paper makes an analysis of the change trend and spatio-temporal evolution characteristics of farmland fragmentation in different counties as well as a theoretical analysis of the driving factors.  Result  1) Spatially, the fragmentation of farmland in Jiaxing City has deomonstrated a gradual decrease from the middle to the North and South. 2) In terms of time, the coefficient of variation of the comprehensive index of farmland fragmentation was 0.040 in 2009 and gradually increased to 0.056 in 2013. 3) In 2012, Jiaxing promoted the comprehensive rural land consolidation on a large scale, which changed the trend increasing farmland fragmentation and reduced the spatial difference of farmland fragmentaion in each county, the coefficient of variation of the comprehensive index of farmland fragmentation decreased to 0.041 by 2018.  Conclusion  It is necessary to further promote the comprehensive consolidation of rural land, innovate and improve the renovation mode and include the control of fragmentation and the promotion of connectivity of farmland as part of farmland protection assessment so as to reduce the fragmentation of farmland fragmentation. [Ch, 2 fig. 2 tab. 21 ref.]
[Abstract](40) [HTML](15) [PDF](5)
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Objective  Puzhehei watershed has a unique natural landscape and a special karst lake ecosystem. This study aims to investigate the distribution characteristics of heavy metals in lake sediments and make ecological risk assessment, which is of great significance to the protection and pollution control of lake water environment in the region.  Method  The levels of six types of heavy metals (As, Cr, Cu, Zn, Mn, and Ni) in surface water and sediments in the basin were analyzed by geo-accumulation index evaluation and potential ecological risk index, and ecological risks of heavy metals were evaluated and the source was traced back.  Result  (1) The mass concentration of heavy metals in the surface water of Puzhehei Basin was far below the Class Ⅰ standard limit of “Surface Water Environmental Quality”. (2)The average mass fraction of heavy metal in the sediments was higher than their corresponding background values (except Cr). (3)The average value of heavy metals in the sediments detected was Mn, Zn, Cu, Cr, Ni and As in descending order, which were 1.68, 1.33, 3.33, 0.96, 1.01 and 1.59 times of their background values, respectively. The pollution degree of Ni was the lowest, with 96.6% of the sampling points being clean. As was moderately polluted, which was 1.8 times of Mn, and the clean level of Mn was similar to that of light pollution. (4)The ecological risk index of individual heavy metal in descending order was As, Cu, Ni, Cr, Mn and Zn, and the potential ecological risk index values were all less than 40, indicating low risk.  Conclusion  As and Cu are the two heavy metals with the largest pollution range and the highest degree in Puzhehei watershed, while Cr, Ni and Zn are mostly pollution-free. In the potential ecological risk evaluation, the average ecological risk index is 31.7. As and Cu contribute most to this risk, and all heavy metals are at low ecological risk. From the perspective of spatial distribution, the National Wetland Park in the lower reaches of the river basin and the estuaries of the three rivers are the main gathering areas of heavy metals. [Ch, 6 fig. 7 tab. 40 ref.]
[Abstract](38) [HTML](8) [PDF](2)
Abstract:
Objective  The purpose of this study is to investigate the effects of organic fertilizer (rapeseed cake), conditioner (shell sand), and carbon based fertilizer on soil nitrogen and phosphorus loss and rice yield of Oryza sativa.  Method  The five treatments of this study were no fertilization(ck), conventional fertilization(T1), organic fertilizer substitution(T2), conventional fertilization+conditioner(T3), and carbon based fertilizer(T4). The amount of nitrogen(N), phosphorus pentoxide(P2O5) and potassium oxide(K2O) used in different fertilization treatments were 270, 75 and 150 kg·hm−2. The effects of different fertilization treatments on nitrogen and phosphorus loss were studied by comparing the nitrogen and phosphorus contents in soil, rice yield, rice grain and straw before and after fertilization among the five treatments, combined with the monitoring results of nitrogen and phosphorus concentration in runoff from June to September.  Result  Fertilization significantly increased nitrogen and phosphorus accumulation in rice grain and straw as well as rice grain yield. Compared with ck, the four treatments increased grain yields by 51.22%−63.41% (P＜0.05), but there was no significant difference among the four treatments. The loss of nitrogen and phosphorus of the five treatments were 4.91−9.56 kg·hm−2 and 0.70−1.35 kg·hm−2 respectively, and the descending order of loss was T2, T1, T3, T4 and ck. The runoff rates of nitrogen and phosphorus of the four fertilization treatments were 0.82%−1.72% and 0.65%−1.99%, respectively and the descending order was T2, T1, T3 and T4.  Conclusion  The application of conditioner and carbon based fertilizer can effectively increase rice yield and reduce the loss of nitrogen and phosphorus (P＜0.05), but organic fertilizer treatment has the maximum runoff loss. Therefore, it is necessary to pay attention to the time and method of fertilization to effectively reduce nitrogen and phosphorus loss and environmental pollution. [Ch, 5 fig. 4 tab. 32 ref.]
[Abstract](45) [HTML](15) [PDF](23)
Abstract:
Objective  With an investigation of the differences of fiber morphology, mechanical properties and dry shrinkage properties in different parts of moso bamboo(Phyllostachys edulis), this study is aimed to provide basic data for the efficient utilization of moso bamboo.  Method  With fiber segregation, microscopic observation as well as tests of the mechanical properties and dimensional stability, a comparative analysis was conducted of the performance differences.  Result  The fiber length, width, and fiber proportion parameters were significantly different in different parts of bamboo (P＜0.01). The length-width ratio of fiber in bamboo outer layer was similar to that in the inner layer, but significantly lower than that in the middle layer(P＜0.01). Because of the dense vascular bundle distribution, the bamboo outer layer had the most significant contribution to the flexural strength and elastic modulus of bamboo samples, followed by the bamboo middle layer and then the bamboo inner layer. In terms of compression strength parallel to grain, the outer layer outperforms the inner layer and the middle layer (with a successive decrease). The horizontal dry shrinkage of bamboo was significantly greater than that of the longitudinal, and the total dry shrinkage was the largest in radial direction, followed by that of tangential direction and longitudinal direction. In different parts of the bamboo, the air-drying shrinkage rate in radial direction is slightly different from that in the tangential direction.  Conclusion  The properties of different parts of bamboo are obviously different, and the compressive property of the inner layer is better than that of the middle layer and with a certain structural design, the inner layer can be retained to prepare new bamboo-wood composite materials, which is conducive to improving the utilization rate of bamboo. [Ch, 2 fig. 5 tab. 37 ref.]
[Abstract](40) [HTML](12) [PDF](27)
Abstract:
Objective  With a comparison of the four commonly used methods for staining Caenorhabditis elegans lipid droplets, this study is aimed to figure out the most suitable dyeing method for Bursaphelenchus xylophilus lipid droplets.  Method  Four were used to fix and characterize After the distribution of lipid droplets in B. xylophilus was defined with its features revealed employ four dyeing methods including Sudan black B staining, Nile red staining, oil red O staining, and post-fix oil red O staining, the stained nematodes were observed and photographed microscopically, and then ImageJ software was used to count the subcutaneous and intestinal lipid droplet pixels.  Result  1) The four dyeing methods have a certain dyeing effect on the lipid droplets of B. xylophilus. 2) Upon the observation of the lipid droplets after microphotographing and the comparison of the pixel intensity after image processing by ImageJ software, the stained lipid droplets pixels with Sudan black B, Nile red, oil red O and post-fix oil red O are 200×1017 m2, 41.64×1012 m2, 52.12×1017 m2, and 83.85×1017 m2 respectively. 3) Lipid droplets stained by Sudan black have the highest average pixel intensity, and lipid droplets stained by Nile red have the lowest average pixel intensity, whereas the lipid droplets stained by post-fix oil red O, after calculation and conversion, produced a consistent characterization with the original image, with a favorable separation of individual lipid droplet.  Conclusion  In conclusion, in light of the simplicity of the dyeing method, the length of dyeing time and the effect of dyeing, the improved post-fix oil red O method is the optimal method for dyeing lipid droplets in B. xylophilus, with the size and distribution of lipid droplets clearly shown. [Ch, 4 fig. 1 tab. 17 ref.]
[Abstract](111) [HTML](23) [PDF](159)
Abstract:
Objective   Terraces are the most important soil and water conservation measures and agricultural production measures in the Loess Plateau, the main region of soil and water loss and the key region of ecological environmental construction in China. The purpose of this study is to obtain the distribution information of loess terraces in a long time series efficiently and accurately, so as to monitor and evaluate soil and water loss in the Loess Plateau.   Method   Google Earth Engine (GEE), a cloud-based platform of remote sensing with high-performance computing resources, was used in this study. Guyuan City of Ningxia, a gully region of the Loess Plateau, was taken as the research area. The recognition accuracy of three machine learning algorithms, including random forest (RF), decision tree (CART) and support vector machine (SVM), was compared by using remote sensing image supervised recognition technology, and the optimized application of LandTrendr algorithm in long-time series dynamic monitoring was discussed. Finally, the distribution of terraces in Guyuan City in recent 30 years was obtained.   Result   1)The order of identification accuracy of the three algorithms from large to small was RF, CART, and SVM. 2) Using random forest algorithm to identify terraces, the overall accuracy based on sample test was 94.10%, Kappa coefficient 0.87, and the overall accuracy based on field patch test was 93.33%, Kappa coefficient 0.80. 3) LandTrendr algorithm can effectively correct the errors in the time series and improve the accuracy of time series identification. 4) From 1988 to 2019, the area of terraces in Guyuan decreased by 45.90%. 5) The time to use terraces in the west of Guyuan was longer than that in the east.   Conclusion   The RF machine learning algorithm combined with LandTrendr algorithm on GEE can efficiently and accurately monitor long-term and large-scale loess terraces. In the past 30 years, the proportion of terrace agriculture in Guyuan City has gradually declined, which promotes the sustainable development of ecological environment. [Ch, 4 fig. 3 tab. 22 ref.]
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2021, 38(3): 433-444.   doi: 10.11833/j.issn.2095-0756.20200474
[Abstract](276) [HTML](51) [PDF](121)
Abstract:
Objective  This study aims to investigate the regulation of OfNAC genes on flower opening of Osmanthus fragrans.  Method  From the transcriptome data of O. fragrans ‘Yanhonggui’, the related OfNAC g enes were screened and analyzed to predict the physicochemical properties and structure. Real-time fluorescence quantitative PCR was used to analyze the expression characteristics of the flower opening process.  Result  22 OfNAC sequences were screened from transcriptome. Bioinformatics analysis showed that all of the 22 OfNAC transcription factors contained NAM domains, and the amino acid sequence contained 5 conserved subdomains (A−E). The sequence of conservatism ranging from strong to weak was C, A, D, B, and E. The proportion of different structures in the secondary structure from large to small was random coils, α-helices, extended strands, and β-sheets. Subcellular localization and transmembrane structure prediction showed that OfNAC17, OfNAC17-X2, OfNAC53, OfNAC91, OfNTM1-9 were membrane-bound transcription factors, and most OfNACs were located in the nucleus. During the O. fragrans flowering process, the relative expression levels of OfNAC100-2, OfNAC43 and OfNAC73 reached the peak at the boll stem stage (S4), and then decreased. The relative expression of OfNAC43 was the highest at the boll stem stage (S4). The relative expression of OfNAC71, OfNAC29-1, and OfNAC21/22 increased slowly from the initial stage (S1), reached the highest at the apical shell stage, and then decreased as a whole. The relative expression of OfNAC29-2 increased sharply at the bead stage (S2) and reached the lowest at the boll stem stage (S4).  Conclusion  It is speculated that OfNAC100-2, OfNAC43, OfNAC73, OfNAC71, OfNAC29-1, OfNAC21/22, OfNAC29-2 may be involved in the regulation of O. fragrans flower opening. [Ch, 6 fig. 3 tab. 33 ref.]
2021, 38(3): 445-454.   doi: 10.11833/j.issn.2095-0756.20200488
[Abstract](166) [HTML](43) [PDF](28)
Abstract:
Objective  The shading caused by the community is one of the important factors that lead to the endangerment of Magnolia sinostellata. Therefore, it is important to conduct a systematic analysis and research of PIF family transcription factors which play an important role in light signal transduction and plant growth. Also, such analysis will help lay a foundation for the exploration of its role in the light signal transduction mechanism of M. sinostellata.  Method  With the transcriptome data of M. sinostellata collected, transcription factors of PIF family were identified and analyzed by bioinformatic while the expression patterns were analyzed employing the qRT-PCR technology.  Result  The nine MsPIFs transcription factor genes screened from the M. sinostellata enjoyed a length of 188−735 aa, a protein size of 20314.56−78957.02 Da, and a theoretical isoelectric point range of 5.18−8.22. The proteins encoded by MsPIFs gene were unstable proteins, and all proteins were hydrophilic proteins localized in the nucleus as was demonstrated in the subcellular localization prediction. All nine proteins have Ser, Thr and Try phosphorylation sites. As was shown in the qRT-PCR results, under extreme shading conditions, there was the occurrence of changes of different degrees in the gene expression of 9 MsPIFs families of which MSBHLH23 has an expression level that was 52.77 and 20.03 times higher than that of the control at 5 d and 10 d after shading treatment.  Conclusion  The PIF transcription factor family of M. sinostellata can respond to shading and this study has laid a foundation for the identification of MsPIFs biological function. [Ch, 7 fig. 3 tab. 32 ref. ]
2021, 38(3): 455-463.   doi: 10.11833/j.issn.2095-0756.20200458
[Abstract](179) [HTML](41) [PDF](23)
Abstract:
Objective   This study aims to analyze the characteristics of long terminal repeat retrotransposons (LTR-REs) in moso bamboo genome, so as to promote the research on the function of LTR-REs in moso bamboo genome and the genetic diversity of bamboo resources.   Method   Based on bioinformatics methods, LTR retrotransposons in the second edition of moso bamboo genome were annotated and classified by LTRharvest and RepeatMakser software, and the distribution characteristics, evolution characteristics and insertion time of the obtained LTR retrotransposons were analyzed.   Result   A total of 1 014 565 LTR retrotransposons and 1 562 families were identified, accounting for 54.97% of moso bamboo genome. Among them, the ratio of solo LTR retrotransposons to intact LTR retrotransposons (S/F) was relatively high (about 1.77∶1.00), indicating that a higher frequency of illegitimate recombination and unbalanced recombination might have occurred in the LTR-REs of moso bamboo genome. LTR retrotransposons were divided into Ty1-copia and Ty3-gypsy superfamilies, and ten lineages included Tork, Reftrofit, Sire, Oryco, Del, Reina, Crm, Tat, Galadriel, and Athila. The preference of Ty1-copia and Ty3-gypsy superfamiles for PBS sites showed an opposite tendency. The longer LTR retrotransposons had longer LTR sequences and more complete structures. The insertion time of LTR retrotransposon in moso bamboo was mainly concentrated in the 0−2.0 Ma region, and it was still in a state of slow growth.   Conclusion   The high-quality assembly of the second edition of moso bamboo genome can better annotate and analyze the LTR retrotransposons in moso bamboo genome. The LTR harvest method based on structure prediction can more accurately predict the LTR retrotransposons of moso bamboo. The LTR retrotransposons of different lineages have different differentiation and amplification activities during evolution. LTR retrotransposons are generally in a state of continuous amplification, which is one of the reasons for the large genome of moso bamboo. [Ch, 3 fig. 3 tab. 52 ref.]
2021, 38(3): 464-475.   doi: 10.11833/j.issn.2095-0756.20200454
[Abstract](121) [HTML](14) [PDF](23)
Abstract:
Objective  This study is aimed to investigate the structural features and the evolutionary patterns of the LBD transcription factor family as well as their expression patterns throughout the embryonic development in Carya illinoensis.  Method  With bioinformatic software employed, efforts were made to identify the LBD gene and analyze its gene structure characteristics, phylogeny relationships and evolutionary history in flower plants, as well as their expression patterns at the three key stages througout the embryonic development.  Result  Within the whole genome in C. illinoensis there were a total of 52 candidate LBD genes which, in terms of gene structure, maximum likelihood phylogenetic tree and motif analysis, could be classified into 3 categories: Group Ⅰ, Group Ⅱ and Group Ⅲ. After the multiple sequences alignment analysis three important structures in the LOB domains of 52 LBD genes were identified, namely the CX2CX6CX3C zinc finger structure, the highly conserved glycine GAS structure and the leucine zipper-like structure with the occurrence of specific mutations or deletions in each of them. According to the LBD gene family phylogenetic analysis of representative flowering plants, Group Ⅰ and Group Ⅱ are relatively conservative, while all LBD genes in Group Ⅲ share a longer branch which indicates that they have undergone greater variation and new functions have been differentiated. The expression analysis showed that the LBD gene family participates in the function of regulating the development of embryos, usually with control over the development and morphogenesis of cotyledons and there is a cluster of genes in the LBD gene of hickory pecans that are highly expressed during the entire embryo development process playing a highly significant role.  Conclusion  A total of 52 LBD genes were obtained in the whole genome of C. illinoensis, which can be divided into three different subfamilies with different gene structures, protein structures, evolutionary patterns, and expression patterns, and these subfamilies, according to the transcriptome expression analysis, are differentially expressed at different stages of embryonic development, and involved in the regulation of C. illinoensis embryo development collectively. [Ch, 5 fig. 2 tab. 47 ref.]
2021, 38(3): 476-484.   doi: 10.11833/j.issn.2095-0756.20200390
[Abstract](127) [HTML](30) [PDF](21)
Abstract:
Objective  With an analysis of the codon usage characteristics of the rbcL genes in Lythraceae species, this study is aimed to clarify the influencing factors of codon bias, and screen the optimal receptor for heterologous expression and genetic transformation.  Method  After rbcL gene CDS of 20 Lythraceae species were obtained from NCBI, CodonW, EMBOSS, and DAMBE software were utilized to compute relevant parameters of gene base composition and codon usage bias before an analysis is conducted of the usage bias of such genes and its incluencing factors using SPSS and Origin software.  Result  The GC content of the rbcL gene from Lythraceae species ranged from 0.425 to 0.437, with GC3s being 0.275 to 0.300 and there was a significant correlation between GC3s, GC, and ENC(P＜0.01). As was shown in the analysis of ENC-GC3s plot, the neutral plot and PR2, natural selection pressure affected the codon usage bias of the rbcL gene from Lythraceae species more heavily than mutation pressure. The result of clustering analysis based on RSCU is partially consistent with that of the neighbor-joining tree based on CDS. Compared with the average codon usage frequency of the rbcL gene from the 20 Lythraceae species, Escherichia coli, Saccharomyces cerevisiae, Arabidopsis thaliana, Nicotiana tabacum, and Solanum lycopersicum possessed 28, 26, 20, 19 and 17 codons, respectively, with significant differences in usage frequency.  Conclusion  In terms of the base composition of the rbcL gene from 20 Lythraceae species, there was a tendency towards A/T bases and codons with A/T base at ther termonal were generally preferred. Also, of all the factors having an influence on codon bias, natural selection pressure was the most important one. Systematic clustering is a good complement for phylogenetic analysis. S. cerevisiae is more suitable as a heterologous expression receptor, while S. lycopersicum is more suitable to act as a receptor material for genetic transformation and function research of rbcL gene. [Ch, 6 fig. 3 tab. 32 ref.]
2021, 38(3): 485-493.   doi: 10.11833/j.issn.2095-0756.20200509
[Abstract](116) [HTML](21) [PDF](33)
Abstract:
Objective  The objective of this study is to explore the distribution characteristics of soil carbon and nitrogen under different vegetation types in Zibaishan National Nature Reserve, and analyze its main influencing factors.  Method  Soil samples were collected from different soil layers, including loam types (Q. aliena forest and P. armandii forest) and sandy types (Q. aliena var. acuteserrata forest, Q. variabilis forest, B. platyphylla forest). The content, density and storage of soil organic carbon (SOC), total nitrogen (TN), and carbon-nitrogen ratio (C∶N) under 5 different vegetation types were compared, and the relationship between SOC, TN, C∶N and soil physical and chemical properties was analyzed.  Result  (1)The content, density and storage of SOC and TN in the loam soil were significantly higher than those in the sandy soil (P＜0.05). As for loam soil, Q. aliena forest had the largest content, density and storage of SOC and TN, followed by P. armandii forest. For sandy soil, the order from large to small was B. platyphylla forest, Q. aliena var. acuteserrata forest, and Q. variabilis forest. (2)With the increase of soil depth, the content, density and storage of SOC and TN in 0−30 cm soil layer decreased significantly (P＜0.05). (3)Soil C∶N in different soil layers of different vegetation types showed little regularity or differences. The value of C∶N was 9.94−16.23, indicating strong mineralization ability of organic matter. (4)Soil water content (SWC) and bulk density (BD) were the main factors affecting soil SOC and TN content, while SWC and pH were the main factors affecting C∶N.  Conclusion  There are significant differences in content, density and storage of SOC and TN under different vegetation types, and SWC is a key factor affecting SOC, TN and C∶N. This study has a certain reference value for the protection and management of forest ecosystem in the reserve. [Ch, 4 fig. 5 tab. 36 ref.]
2021, 38(3): 494-501.   doi: 10.11833/j.issn.2095-0756.20200326
[Abstract](141) [HTML](26) [PDF](33)
Abstract:
Objective  With an examination of the effects of simulated nitrogen deposition and phosphorus addition on the soil respiration in Chinese fir(Cunninghamia lanceolata) forest, this study is aimed to provide scientific basis for the regulation of the soil carbon cycle in Chinese fir forest.  Method  In an attempt to investigate the changes in soil respiration in Chinese fir forest under atmospheric nitrogen deposition and phosphorus addition, a 10-year-old Chinese fir forest was selected as the research object with a total of 9 treatment levels, namely the control treatment group (ck), low nitrogen (N30: 30 kg·hm−2·a−1), high nitrogen (N60: 60 kg·hm−2·a−1), low phosphorus (P20: 20 mg·kg−1), high phosphorus (P40: 40 mg·kg−1), low nitrogen and low phosphorus (N30+P20), low nitrogen and high phosphorus (N30+P40), high nitrogen and low phosphorus (N60+P20), high high nitrogen and high phosphorus (N60+P40).  Result  The application of nitrogen and phosphorus had a significant effect on the respiration of Chinese fir soil. Nitrogen applied alone promoted the respiration of Chinese fir soil, to the largest degree (P＜0.05) when the nitrogen level reached N60: 60 kg·hm−2·a−1. When the phosphorus level reached P40: 40 mg·kg−1, the soil respiration was most significantly promoted(P＜0.05). With both nitrogen and phosphorus applied, the low nitrogen and high phosphorus treatment level (N30+P40) promoted the respiration most significantly. The soil respiration rate was extremely significantly positively correlated with soil temperature(P＜0.01), and extremely significantly negatively correlated with the soil moisture(P＜0.01). And at low nitrogen and low phosphorus treatment level (N30+P20), the soil temperature sensitivity coefficient(Q10) value was higher than the control.  Conclusion  Both nitrogen deposition and phosphorus addition can promote the soil respiration of Chinese fir and the combined application of nitrogen and phosphorus can promote the soil respiration of Chinese fir more significantly. Among all the treatment levels, the effect of high nitrogen and low phosphorus is the most significant. [Ch, 1 fig. 2 tab. 46 ref.]
2021, 38(3): 502-509.   doi: 10.11833/j.issn.2095-0756.20200505
[Abstract](143) [HTML](34) [PDF](22)
Abstract:
Objective  The study aims to explore the characteristics and laws of the chronological change of rainfall runoff and forest quality in Shicheng County of Jiangxi Province, and the relationship between rainfall, runoff and forest, so as to provide basis for quantitative monitoring and scientific evaluation of soil erosion and ecological environment in the red soil hilly area in southern China.  Method  Based on the natural rainfall and runoff sequence data of Shicheng County from 1989 to 2018 and remote sensing image maps in different years, the methods of wavelet analysis, remote sensing supervision and interpretation, and forest quality grade determination were employed.  Result  (1) Rainfall and runoff showed a slow downward trend with inter-annual changes, but the decreasing trend was not significant. (2) The forest quality index showed an upward-downward-upward trend with the increase of resolution years. (3) The improvement of forest quality had a significant role in flood detention. (4) The wavelet model of Shicheng County showed the runoff depth was positively correlated with precipitation and negatively correlated with forest quality index.  Conclusion  The improvement of forest quality can strengthen the ability of forest water conservation and forest flood detention. [Ch, 4 fig. 5 tab. 27 ref.]
2021, 38(3): 510-522.   doi: 10.11833/j.issn.2095-0756.20200327
[Abstract](135) [HTML](36) [PDF](19)
Abstract:
Objective  The objective of this study is to determine the saturation value of optical remote sensing estimation of spruce-fir forest biomass, and to improve the accuracy of remote sensing estimation of biomass.   Method  Taking the spruce-fir forests in Diqing Tibetan Autonomous Prefecture as the research object, the saturation value of the spruce-fir biomass was calculated by curve fitting, Tibetan Autonomous and the regression estimation model and BP neural network model of the spruce-fir biomass were established using the forest management inventory (FMI) data combined with Landsat 8 OLI remote sensing image in the contract period and the statistical value of remote sensing factor reflectance extracted from the randomly selected small class sample data. At the same time, based on the regression model, single level and nested two-level(region+age group)mixed effect models considering regional and age group effects were constructed to estimate the aboveground biomass of spruce-fir forests in the study area.  Result  The biomass saturation value of the spruce-fir forests in Diqing Tibetan Autonomous Prefecture was 233 t·hm−2 by power function fitting. The adjusted determination coefficient of the optimal regression estimation model \begin{document}$R_{\rm{a}}^{2}$\end{document} was 0.606, which was higher than \begin{document}$R_{\rm{a}}^{2}$\end{document} (0.542) of the BP neural network model. The fitting accuracy and independence test indexes of the mixed model of each effect level were better than those of the regression model. The two-level mixed effect model had the best fitting accuracy, while the mixed model with age group effect level had the best independence test index. The mixed effect model significantly reduced the average residual error of regression model and BP neural network model in the low biomass section (＜100 t·hm−2), especially in the high biomass section (＞233 t·hm−2).  Conclusion  The mixed effect model has a wider estimation range, which can reduce the impact of low overestimation and high underestimation caused by data saturation, and improve prediction accuracy. [Ch, 3 fig. 12 tab. 28 ref.]
2021, 38(3): 523-533.   doi: 10.11833/j.issn.2095-0756.20200393
[Abstract](141) [HTML](43) [PDF](19)
Abstract:
Objective   The objective is to analyze the relationship between vegetation community and environmental factors in Jingzifeng National Forest Park of Qingyuan County, Zhejiang Province.   Method   Data of 48 quadrats in park were classified and sorted, and the relationship between forest community types, distribution characteristics and environmental factors was analyzed based on these data.   Result   (1)A total of 193 species belonging to 129 genera and 66 families were recorded in 48 plots. The families with abundant plant species were Fagaceae (19 species), Lauraceae (18 species), Theaceae (9 species), Ericaceae (9 species), Rosaceae (9 species), Aquifoliaceae (6 species), Gramineae (6 species), Rubiaceae (6 species), Chloranthaceae (5 species) and Liliaceae (5 species). The dominant species in tree layer included Cunninghamia lanceolata, Schima superba, Pinus taiwanensis, Cyclobalanopsis glauca, Castanopsis eyrei, Machilus thunbergii, Engelhardia fenzelii and Alniphyllum fortunei. The dominant species in shrub layer were Maesa japonica, Sarcandra glabra, Eurya muricata, and Rhododendron simsii. The dominant species in herbaceous layer were Pteridum aquilinum var. latiusculum, Dicranopteris dichotoma, Dryopteris fuscipes, Carex chinensis, Imperata cylindrica, Selaginella moellendorfii and Arthraxon hispidus. (2) TWINSPAN divided the vegetation community into 10 cluster types. (3) The distribution of the 10 clusters in DCA ordination diagram was regular, which reflected a good environmental gradient. (4) CCA ordination results showed that the most important environmental factor affecting the distribution of each cluster was altitude, followed by soil type, soil temperature and slope. The distribution characteristics of the dominant tree species were similar to those of each cluster.   Conclusion   Altitude is the most important environmental factor affecting the distribution of vegetation community in Jinzifeng National Park, and the altitude plays a decisive role in the distribution of mountain vegetation community. [Ch, 4 fig. 4 tab. 22 ref.]
2021, 38(3): 534-540.   doi: 10.11833/j.issn.2095-0756.20200455
[Abstract](106) [HTML](41) [PDF](13)
Abstract:
Objective  This study is aimed to clarify the three-dimensional green quantity (3DGQ) and the characteristics of forest recreation space (FRS) of landscape-recreational forests at different niches, and reveal the rules of constructing landscape-recreation forests and the existing problems.  Method  On the basis of the community ecology theory, with 13, 14 and 26 sample plots selected from Qianshan Park, Zhuhai Institute of BIT, and Meihua City Park respectively as the subjects, each tree was surveyed using high-resolution remote sensing images before 3DGQ and FRS were calculated to analyze the differences between different location of landscape-recreation forests.  Result  Qianshan Park, located in the core urban area (CUA), had the lowest 3DGQ density. Michelia × alba, Ficus microcarpa, Cinnamomum camphora, Litchi chinensis, Khaya senegalensis, Ficus altissima, Delonix regia and Cinnamomum burmannii displayed high values of 3DGQ. The three sites showed different spatial distributions of 3DGQ, and Meihua City Park which was located in the core urban area had relatively even distribution of 3DGQ than the others. There was a positive correlation between DBH and 3DGQ, which was related to the crown shapes of trees. In terms of the spatial allocation, for D. regia, Ceiba speciose, Bombax ceiba and C. camphora, superiority was given to FRS, while for M. ×alba, various spatial allocation strategies were adopted.  Conclusion  The 3DGQ density decreases while the distribution of 3DGQ showed a strong central tendency with the location of landscape-recreational forests shifting from the core urban area to the sub-urban area (SUA) and finally to urban fringe area (UFA). The correlation coefficient between DBH and 3DGQ is related to the crown shapes of tree species and the features of different tree species in the progress of the construction of landscape-recreation forest should be taken into consideration in the allocation of canopy space and recreation space. [Ch, 3 fig. 1 tab. 30 ref.]
2021, 38(3): 541-551.   doi: 10.11833/j.issn.2095-0756.20200461
[Abstract](150) [HTML](44) [PDF](26)
Abstract:
Objective  The geographic national conditions data was used to quantitatively study the change trend of landscape ecological risk at the county scale.  Method  Based on the geographic and national conditions data supported by the GIS technology and Fragstats 4.2 software, the landscape index were selected and the geo-statistical methods were used to analyzed the dynamic changes of landscape, spatial-temporal changes of landscape ecological risks and human disturbance activities in Susong County from 2015 to 2017.  Result  In the northwest, landscape fragmentation, landscape separation, landscape fractional dimension, the level of landscape diversity and landscape ecological risks were all lower; In the central and southeast, landscape fragmentation, landscape separation, and landscape sub-dimension were higher which shows that the landscape distribution structure was more complicated, and the landscape ecological risk was higher; The low ecological risk areas, lower ecological risk areas, and medium ecological risk areas were decreasing, while the areas of higher ecological risk areas and high ecological risk areas were increasing.  Conclusion  From 2015 to 2017, the degree of landscape ecological risk in Susong County increased, and the ecological risk level was transformed from a lower level to an adjacent higher level. The ecological risk levels of mineral resource areas, fish and rice towns, transportation hub towns, agricultural areas, and mountain tourist areas were arranged in order from high to low. [Ch, 6 fig. 6 tab. 32 ref.]
2021, 38(3): 552-559.   doi: 10.11833/j.issn.2095-0756.20200351
[Abstract](113) [HTML](22) [PDF](9)
Abstract:
Objective  This research aims to understand the situation of invasive alien plants in Ningbo and assess their invasive risk levels, so as to provide suggestions for the ecological security management.  Method  Typical habitats of alien invasive plants in different areas of Ningbo were investigated by quadrats. The analytic hierarchy process (AHP) was used to comprehensively evaluate indexes such as introduction stage, suitable growth stage, diffusion stage, invasion distribution status, damage impact and management difficulty, so as to determine the invasive risk of the alien invasive plants.  Result  There were 77 species of alien invasive plants in Ningbo, belonging to 27 families and 58 genera. The dominant families of alien invasive plants were obvious, among which Asteraceae was the most, with 21 species, followed by Solanaceae, Leguminosae and Poaceae, with 6 species each. There were 71 species of herbaceous plants, accounting for 92.21% of the total species. 37 species were introduced intentionally, accounting for 48.05% of all invasive plants. 32 species were unintentionally introduced, accounting for 41.56%. There were 8 species (10.39%) whose invasive routes were unknown, accounting for 10.39%. 58 species came from America, accounting for 75.32% of the total number of alien invasive plants in Ningbo. 15 were from Europe (19.48%). AHP showed there were 15 species of alien invasive plants with level Ⅰ risk, 14 species with level Ⅱ risk, 18 species with level Ⅲ risk, 22 species with level Ⅳ risk and 8 species with level Ⅴ risk.  Conclusion  The risk level of alien invasive plants in Ningbo is relatively high. It is suggested that comprehensive measures should be taken to prevent and control the invasive harm of the alien plants according to the assessed risk level. [Ch, 2 tab. 28 ref.]
2021, 38(3): 560-566.   doi: 10.11833/j.issn.2095-0756.20200365
[Abstract](148) [HTML](62) [PDF](12)
Abstract:
Objective   The epidemic situation of Bursaphelenchus xylophilus in Hubei Province is severe. The objective of this study is to investigate the invasion risk and the damage degree of B. xylophilus disease in Hubei Province, so as to provide suggestions and reference for current epidemic prevention and control.   Method   Combined with 3S technology, the ecological niche factor analysis (ENFA) model was used, and 4 factors affecting the colonization and spread of B. xylophilus (climate, vegetation, terrain, human disturbance) were selected to predict and evaluate the invasion risk of the disease.   Result   The high risk area of B. xylophilus disease in Hubei Province covered an area of 38 884.62 km2, accounting for 20.92% of the total area of Hubei Province, mainly concentrated in the central and eastern regions with low altitude and frequent human activities. The moderate risk area was 66 501.84 km2, representing 35.77% of the total area. The low risk area was 80 513.54 km2, representing 43.31% of the total area. These areas were mainly distributed in Jianghan Plain and high-altitude mountains in the west. B. xylophilus preferred to be distributed in coniferous forest areas with high temperature, abundant precipitation, low altitude, close to human settlements and frequent human activities. Through cross-validation to test the prediction of the model, the P/E curve was obtained. The curve was monotonically increasing and the Boyce index was very high, indicating that the model had high accuracy.   Conclusion   The ENFA model can simulate the risk areas of B. xylophilus. The results of the model can provide reference for the prevention and control of B. xylophilus in Hubei Province. [Ch, 2 fig. 3 tab. 25 ref.]
2021, 38(3): 567-576.   doi: 10.11833/j.issn.2095-0756.20200551
[Abstract](93) [HTML](25) [PDF](12)
Abstract:
Objective  The objective of this study is to explore the effect of thinning on the functional traits of roots, stems and leaves of Vitex negundo var. heterophylla under Quercus variabilis plantation in order to provide theoretical basis for the optimization of plantation structure and the regeneration and protection of understory seedlings.  Method  The V. negundo var. heterophylla in the shrub layer of Q. variabilis plantation 3 years after thinning was taken as the research object, and the differences of leaf area, specific leaf area, leaf dry matter content, stem dry matter content, total root length, specific root length and other structural traits, as well as total nitrogen, total phosphorus, total potassium and total organic carbon content in various plant organs were compared. The relationship between plant functional traits and the understory light environment and soil physical and chemical characteristics was studied.  Result  After thinning, the aboveground functional traits of plants of V. negundo var. heterophylla such as total leaf organic carbon, leaf area, specific leaf area, leaf organic nitrogen, stem total organic carbon, and the underground functional traits of plants such as root length, root volume, root biomass, the total organic carbon content of roots were significantly higher than those of the control plot (P＜0.05). Correlation and stepwise regression analysis results showed that scattered radiation was the main factor affecting the structural properties of V. negundo var. heterophylla leaves. Direct radiation flux, photosynthetically active radiation and total solar radiation time were the key factors affecting leaf chemical properties, while stem functional properties were mainly affected by the direct radiation and scattered radiation under the forest. Total root length, specific root length and root organic carbon content were significantly correlated with soil non-capillary porosity, soil total porosity, soil organic carbon and soil total nitrogen (P＜0.05), among which soil organic matter content was the key factor affecting functional traits.  Conclusion  Thinning can significantly promote the development of the functional traits of leaves and roots of Q. variabilis plantation, and has a weak effect on stem functional traits. [Ch, 1 fig. 6 tab. 31 ref.]
2021, 38(3): 577-586.   doi: 10.11833/j.issn.2095-0756.20200358
[Abstract](76) [HTML](22) [PDF](11)
Abstract:
Objective  This study aims to investigate the effects of water stress on the ultrastructure of chloroplast and the activity and content of key enzymes in the flavonoid synthesis pathway of Tetrastigma hemsleyanum, so as to improve the quality of T. hemsleyanum.  Method  With two-year-old seedlings of T. hemsleyanum as materials, and through water control pot experiments (setting waterlogging, drought, and the control), the effects of water stress on chloroplast ultrastructure, root flavonoid content and the activities of three key enzymes [phenylalanine ammonia lyase(PAL), chalcone synthase(CHS) and chalcone isomerase(CHI)] in flavonoid synthesis pathway were analyzed.  Result  Drought and waterlogging both caused the decrease of chloroplast number in the leaves, and they moved toward the center of the cell instead of clinging to the cell wall. Besides, the number of plastid globules in the chloroplast increased and the volume became larger, the color became lighter, and the lamella structure of chloroplast was no longer neat and compact. The total flavonoid content of T. hemsleyanum reached the peak on the 12th day under drought stress, and reached the peak on the 16th day under waterlogging stress. Analysis of key enzyme activities in the biosynthetic pathway of flavonoids showed that the activities of PAL, CHS and CHI increased successively in the early stage of the maximum flavonoid content or during the same period, but with the extension of stress time, the total flavonoid content and key enzyme activities decreased in varying degrees. There was a significant correlation between the content of flavonoids and the activities of PAL, CHS, and CHI (P＜0.05).  Conclusion  Moderate water stress can increase the content of flavonoids in the roots of T. hemsleyanum and enhance the activity of related enzymes. [Ch, 7 fig. 1 tab. 36 ref.]
2021, 38(3): 587-596.   doi: 10.11833/j.issn.2095-0756.20200291
[Abstract](122) [HTML](108) [PDF](69)
Abstract:
Objective  This study aims to investigate the composition of anthocyanins and the effects of physical and chemical factors on the stability of anthocyanins in Lycoris sprengeri.  Method  The anthocyanins in the flower were determined by liquid chromatography-mass spectrometry (LC-MS). The effects of temperature, light, pH value and metal ions on the color change of anthocyanins in L. sprengeri were studied by ultraviolet spectrophotometry and HPLC-ADA.  Result  (1) Cyanidin, pelargonidin and delphindin were the main components of anthocyanins in L. sprengeri. (2) The anthocyanin solution was stable when temperature was lower than 30 ℃, dark and pH value ≤ 3.0. High temperature, strong light and high pH value could degrade anthocyanins, and the degradation degree increased with time. Al3+, Fe2+, Cu2+ and Fe3+ all changed the color of anthocyanin solution, and Ca2+, Zn2+, Mg2+ and K+ had little effect on the color of anthocyanins, but the metal ion concentration of 0−0.01 mol·L−1 had a certain effect on the color of anthocyanins. Hyperchromic effect of Fe2+ was more obvious when Fe2+ concentration increased. (3) High temperature, strong light and pH value had some effects on the concentration of anthocyanins. The concentration of cyanidin 3-O-glucoside decreased with the increase of time, light and temperature, while that of pelargonidin-3-O-glucoside showed the opposite trend. Delphinidin-3-O-glucoside was stable under different light and temperature conditions. With the increase of pH value, the mass concentration of cyanidin-3-O-glucoside decreased gradually, while delphinidin-3-O-glucoside increased gradually.  Conclusion  The main components of anthocyanins in L. sprengeri are cyanidin, pelargonidin and delphinidin. High temperature, strong light and high pH value can degrade anthocyanins, which can lead to their structural transformation. [Ch, 7 fig. 1 tab. 29 ref.]
2021, 38(3): 597-604.   doi: 10.11833/j.issn.2095-0756.20200503
[Abstract](76) [HTML](20) [PDF](7)
Abstract:
Objective  This study aims to explore the formation mechanism and antibacterial effect of yak bone protein peptide-calcium chelate embedded with cinnamon essential oil, so as to make full use of the bone resource and improve its utilization rate and avoid serious waste.  Method  The yak bone was autoclaved at high temperature to separate protein and bone residue. Yak bone collagen peptide was obtained from enzymatic hydrolysis of protein, and soluble yak bone calcium was obtained from acid-dissolved bone residue. The cinnamon essential oil and the yak bone collagen peptide were mixed and homogenized to form a cinnamon essential oil-yak bone peptide emulsion, and the calcium chelate of yak bone protein peptide encapsulated in cinnamon essential oil was obtained by high speed shear method. The turbidity, particle size, polydispersity index, antibacterial activity of the chelated calcium were determined and organoleptic evaluation was conducted.  Result  The yak bone peptides were mostly small molecule peptides (less than 1.0 kDa), and were suitable for the preparation of chelated calcium. When pH value was less than 7, many yak bone peptides were negatively charged and were affected by hydrophobicity to form yak bone protein peptide-calcium chelates. The yak bone peptide was composed of a large number of proline (P) and glycine (G), which could easily form the β-turn, one of the polypeptide secondary structures, and facilitate the release of substances. The yak bone protein peptide-calcium chelate embedded with cinnamon essential oil had good stability, with an average particle size of 780.2 nm. The dispersibility was good and the polydispersity index was less than 0.2. The 12 h antibacterial rates of yak bone protein peptide, cinnamon essential oil and chelate against Aeromonas veronii were −13.70%, 70.24% and 77.33%, respectively. The inhibition rate of chelate to Aeromonas was higher than that of cinnamon essential oil after 6 hours. The organoleptic evaluation revealed that the aroma scores of chelate and cinnamon essential oil were 7.15 and 4.35 respectively, and the cinnamon flavor of chelate was significantly stronger than that of cinnamon essential oil (P＜0.05), indicating that the chelate had a certain sustained-release effect.  Conclusion  Yak bone protein peptide and yak bone calcium are suitable for the development of complex amino acid mineral chelated calcium products, and the yak bone protein peptide-calcium chelate encapsulated with cinnamon essential oil can be used for the development of new antibacterial agents. [Ch, 4 fig. 4 tab. 33 ref.]
2021, 38(3): 605-612.   doi: 10.11833/j.issn.2095-0756.20200391
[Abstract](75) [PDF](4)
Abstract:
Objective  This study is to analyze the applicability of low-alkali and low-salt reactive red dyes in veneer dyeing, with the purpose of reducing the pollution of dyeing wastewater and the cost of production.  Method  A new low-salt reactive red dye(SNE) and low-alkali reactive red dye(LA) were selected to dye Xylosma japonicum veneers with poor permeability. The widely used reactive red dye (M-3BE) was used as control. The substantivity, reactivity, fixation rate and dyeing effects were tested. Fourier transform infrared spectroscopy(FTIR), thermal gravimetric(TG) analyzer and scanning electron microscopy(SEM) were used to analyze the changes of functional groups, wood components and microstructure of specimens.  Result  Compared with M-3BE, when the dosages of Na2SO4 and Na2CO3 were reduced to 1/2 and 1/8 respectively, the fixation rate of SNE increased by 15.33% and color difference decreased by 1.35%, while the fixation rate of LA decreased by 3.37% and color difference increased by 2.03%. After dyeing, the hydroxyl content on the wood surface decreased, and the lowest hydroxyl content was detected on the X. japonicum wood surface dyed with SNE dyes. No new absorption peak was observed on the dyed X. japonicum veneers except weak sulfate S=O absorption peak. The mechanism and the functional group structure between three reactive dyes and wood were similar. The thermal decomposition curves were slightly different due to differences in the parent structures of the three reactive dyes. All dye molecules could diffuse to the wood interior from the wood surface, and the order of diffusion degree from large to small was SNE, M-3BE, and LA.  Conclusion  SNE has high dye uptake and LA has excellent color effect, which can greatly reduce the discharge of electrolyte salt and alkali. [Ch, 3 fig. 3 tab. 28 ref.]
2021, 38(3): 613-623.   doi: 10.11833/j.issn.2095-0756.20200482
[Abstract](143) [HTML](43) [PDF](19)
Abstract:
Global warming, a global ecological and environmental problem, attributes to the rapidly increased emission of greenhouse gases of which N2O ranks the third in the atmosphere after CO2 and CH4. On the one hand, nitrification and denitrification often take place in the process of forest soil nitrogen mineralization where N2O is produced from soils, thus, increasing the atmospheric N2O concentration. On the other hand, forest soil nitrogen mineralization, as a complex ecological process, is regulated by the interactions of biotic and abiotic environmental factors. Therefore, the investigation of the influencing factors and the regulatory mechanism of forest soil nitrogen mineralization, is conducive to the promotion of people’s understanding of the nitrogen cycling process of forest soils, thus playing an important role in the study of global change. However, previous studies on the nitrogen mineralization of forest soils were mainly limited to the effect of single factors with the lack of comparable research results, the cooperative regulation research on multiple factors (e.g., microbial-animal interaction), the study of forest soil nitrogen mineralization characteristics and impact mechanism under different circumstances of climate and land-use, and the research on the response of nitrogen mineralization to global climate change. Aimed to provide theoretical support for better understanding the spatiotemporal patterns of forest soil nitrogen mineralization in different climatic areas and their effects on global climate change, this study has conducted an examination of the spatiotemporal variations and the influencing factors of forest soil nitrogen mineralization, and provided an explanation of the characteristics and mechanism of the effect of abiotic (e.g., soil physicochemical environments) and biotic factors (e.g., forest vegetation cover, forest litter, and soil microorganisms and fauna) on forest soil nitrogen mineralization. It is advised that researches on soil nitrogen mineralization should, with unified and efficient methods, be focused on the influencing mechanism of the multi-factor coupling of soil microorganisms-fauna-environmental factors on forest soil nitrogen mineralization, the regulation mechanism of soil nitrogen mineralization under different climate and land-use circumstances, as well as the processes and mechanisms of forest soil nitrogen mineralization under the background of global change. [Ch, 69 ref.]
2021, 38(3): 624-633.   doi: 10.11833/j.issn.2095-0756.20200346
[Abstract](234) [HTML](50) [PDF](16)
Abstract:
As part of the AP2/ERF superfamily, ethylene response factors (ERF) enjoys a structure featured with an AP2 domain and conserved motifs with different functions outside the AP2 domain. With previous reseaches, ERF positively regulates plant resistance under stress, but it can also negatively regulate plant resistance for certain reasons. ERF regulates fruit ripening by regulating the changes of pigment and softening and controls the longevity of flowers and leaves by regulating the process of senescence and abscission. ERF is regulated by signal molecules to start transcription, and then regulated by other mechanisms to complete the expression. ERF can achieve a wide-range regulation of the downstream genes by regulating signal molecules. The interaction between ERF and protein enriches the way in which ERF regulates downstream genes. And this study, based on what has been previously researched, is aimed to conduct a review of the structural characteristics, biological functions and expression regulation mechanism of ERF so as to provide a reference for future studies on ERF. [Ch, 1 fig. 1 tab. 77 ref.]
2021, 38(3): 634-643.   doi: 10.11833/j.issn.2095-0756.20200338
[Abstract](290) [HTML](88) [PDF](17)
Abstract:
Transposable elements (TEs) can be moved by means of transposition or reverse transposition in the genome of an organism, whose copy number in large numbers is an important factor for genome instability. Therefore, it is the direction of host evolution to maintain TEs silence. DNA methylation, generally considered to be a heritable epigenetic modification method for silencing TEs, plays a role in the maintainance of genome stability, genetic imprinting and the regulation of gene expression. This study is aimed at an overview of the impact of TEs on the evolution of biological genome and gene expression, a summary of the latest research progress of transposon silencing mechanism dominated by DNA methylation, and an investigation of the mechanism of environmental factors that regulate transposon jumping via DNA demethylation. [Ch, 4 fig. 82 ref.]
2021, 38(3): 644-651.   doi: 10.11833/j.issn.2095-0756.20200492
[Abstract](277) [PDF](10)
Abstract:
Objective   The objective of this study was to screen the stable expression of internal reference genes of Melanotus cribricollis larvae infected by Metarhizium pingshaense, so as to lay a foundation for the research on related gene expression in this bamboo wireworm.   Method   Based on the transcriptome data of M. cribricollis larvae, the correlation (R2) and amplification efficiency were analyzed by qRT-PCR with specific primers. The 6 candidate reference genes including β-actin, GAPDH, α-tubulin, RPL13α, RPS3 and RPS27a were evaluated by GeNorm, NormFinder and BestKeeper softwares. The stabilities of selected candidate reference genes including PRS27a and RPS3 were further validated by analyzing the expression of 6 target genes.   Result   GeNorm analysis showed that the expression of PRS27a and RPS3 were the most stable, followed by α-tubulin, RPL13α, β-actin and GAPDH. The most suitable number of internal reference genes was 2. NormFinder analysis showed that the expression of RPL13α was the most stable, followed by α-tubulin, RPS3, RPS27a, β-actin, and GAPDH. BestKeeper analysis showed that the P values of β-actin and GAPDH were ＞0.5, which were not suitable for reference genes under the condition of this experiment. There were some differences in the ranking of candidate internal parameters obtained by different software analysis. Comprehensive analysis and expression stability verification showed that PRS27a or RPS3 were the best internal reference genes, and the expression levels of 6 target genes were basically the same.   Conclusion   PRS27a and RPS3 were the most appropriate reference genes for qRT-PCR analysis in bamboo wireworm infected by M. pingshaense. [Ch, 3 fig. 3 tab. 27 ref.]
2021, 38(3): 652-658.   doi: 10.11833/j.issn.2095-0756.20200302
[Abstract](79) [HTML](18) [PDF](8)
Abstract:
Objective  This paper with an analysis of the influencing factors of natural regeneration of Abies georgei var. smithii in Sejila Mountain, is aimed to provide theoretical guidance for the effective promotion of its natural regeneration.   Method  Based on a field sample survey as well as an analysis of the correlation between the seedlings density and the five influencing factors on shady and sunny slopes of A. georgei var. smithii in Sejila Mountain, the path analysis was carried out to find out the key factors affecting its natural regeneration.   Result  On both sunny and shady slopes, there was a significant positive correlation between the natural regeneration seedlings and the length of seed wing, 1000-seed weight, moss thickness, litter thickness, canopy density of sunny slope. Litter thickness was the most important factor affecting the growth of natural regeneration seedlings of A. georgei var. smithii on sunny slope and the order of contribution to seedlings density was litter thickness, 1 000-seed weight, moss thickness, winged seed length and canopy density. Moss thickness was the most important factor affecting the growth of natural regeneration seedlings of A. georgei var. smithii on shady slope and the order of contribution to seedlings density was moss thickness, litter thickness, 1000-seed weight, canopy density and winged seed length.  Conclusion  Litter thickness was the largest factor affecting the density seedlings of A. georgei var. smithii on sunny slope, while moss thickness on shady slope was the most critical factor. [Ch, 3 tab. 27 ref.]