2019 Vol. 36, No. 6
To determine the effect of biochar application on adsorption capacity of contaminants from soils, biochars derived from dead pigs (PB) and Platanus orientalis branches (POB) were selected. A batch equilibration method was used to explore the underlying mechanisms of kinetic and thermodynamic adsorption. Treatments included an untreated control, 2% PB-treated soil, and 2% POB-treated soil, and were replicated three times. Results indicated that both PB and POB enhanced adsorption capacity of Zn2+ from a Zn2+-DEP(diethyl phthalate) composite solution(P < 0.05), and the capacity increased with an increase of biochar application rates(P < 0.05). Compared with the untreated control, saturated adsorption increased 31.61% in the 2% PB-treated soil, which was 5.90 times that of the 2% POB-treated soil. Additionally, adsorption kinetics could be well described by a pseudo-second order kinetics model with adsorption processes mainly including liquid film and intraparticle diffusion. The thermodynamic adsorption process was a spontaneous endothermic reaction primarily controlled by a hydrogen bonding force. In addition, the application of DEP obviously promoted the adsorption of Zn2+ onto the soils(P < 0.05). This study could provide a scientific reference for the application of biochars in the remediation of soils contaminated with both heavy metals and phthalate esters (PAEs).
To reveal improvements from different plant restoration and treatment measures on soil physical properties of quarries, five typical plant types:Populus tomentosa, Platycladus orientalis, Pinus tabuliformis, Cotinus coggygria, and Pinus tabuliformis + Cotinus coggygria were selected and evaluated comprehensively and for soil physical properties using ANOVA and principal component analysis on soil bulk density, field water holding capacity, and soil porosity. Results showed that (1) After ecological restoration of the quarry, soil particle size for the five plant recovery types was mainly distributed in the range of 0.25-10.00 mm. (2)Soil bulk density and porosity presented significent difference, except Pinus tabuliformis, under the ANOVA(P=0.05). Compared to the Platycladus orientalis recovery type, soil bulk density of the other four restoration types decreased 2.51%-29.83%, soil porosity increased 7.49%-24.16%, and water holding capacity increased 3.74%-24.03%. (3) After treatment by the five different plant restoration types, water holding capacity of the 0-20 cm soil layer was 1.36%-24.30% higher than the 20-40 cm layer. (4) The principal component analysis for soil bulk density, field water holding capacity, and soil porosity showed that soil physical properties in the mining area were Platycladus orientalis > Pinus tabuliformis + C. coggygria > Pinus tabuliformis > C. coggygria > Populus tomentosa. The final comprehensive scores of Platycladus orientalis, Pinus tabuliformis + C. coggygria, and Pinus tabuliformis were approximately the same so these three patterns should be recommended preferentially for ecological quarry restoration.
To understand the distribution characteristics of soil carbon and nitrogen and their labile fractions as well as their relationship with environmental factors (enzyme activities, soil pH, and understory vegetation diversity), soil samples were collected from four vegetation zones (evergreen broadleaf forest, mixed evergreen deciduous broadleaf forest Ⅰ and Ⅱ, and alpine meadow) along an altitudinal gradient (870-1 760 m) on Mount Huangshan. Three 10 m×10 m plots were arranged in each vegetation zones, and 10 sub-samples (0-10 cm depth) were randomly collected in each plot and mixed into one soil sample. Variables tested included soil total organic carbon (TOC), microbial biomass carbon (MBC), dissolved organic carbon (DOC), readily oxidization carbon (ROC), total nitrogen (TN), microbial biomass nitrogen (MBN), dissolved organic nitrogen (DON), soil urease activity, β-glucosidase activity, catalase activity, soil pH, Shannon-Wiener and Simpson diversity indices of the understory vegetation. Analysis included one-way ANOVA and Duncan multiple comparison, Pearson correlation, redundancy analysis, and Monte-Carlo permutation test. Results showed significant differences in soil MBC, DOC, TN, and MBN in different vegetation zones (P < 0.01). The soil microbial quotient (MBC/TOC) and DOC/TOC in different vegetation zones were significantly different (P < 0.01) and generally increased with elevation. The soil MBN/TN (5.79%) in alpine meadows was significantly higher than in other vegetation zones (P < 0.05). Soil urease activities generally decreased with elevation (P < 0.05); whereas, β-glucosidase and catalase activities generally increased with elevation (P < 0.01). The Pearson correlation and redundancy analysis showed that soil labile organic carbon and N fractions were not only dependent on TOC and TN, but also closely related to urease, β-glucosidase, catalase activities, and soil pH. Also, according to the Monte-Carlo permutation test DON had a significant effect (P=0.006) on the distribution of soil enzymes. In conclusion, soil labile organic carbon and N fractions in the Mount Huangshan Forest Ecosystem were directly and indirectly related to vegetation types, and greatly impacted soil enzyme activities.
Through consecutive location tests in northern Henan Province over 6 years and compared with a waste land, the effects of different planting patterns for alfalfa(Medicago sativa) and ryegrass(Bromus inermis) on the composition of soil aggregate structure and vertical distribution of organic carbon were studied using a correlation analysis. The relationship between the two was also discussed. Results showed that morphological structure of the soil aggregates changed after an artificial grassland was planted. Soil dry-sieving aggregates consisted mainly of 2.00-3.00 mm and 3.00-5.00 mm particle sizes (proportion:35.55%-57.12%); whereas, soil water-stable aggregates were composed of particles < 0.25 mm and 1.00-3.00 mm in size (proportion:53.47%-74.47%). The order of fractal dimensions for both dry-sieving aggregates and water-stable aggregates was wasteland > ryegrass single-sowing > alfalfa single-sowing > alfalfa/ryegrass mixed-sowing. Total organic carbon content, soil active organic carbon, and humus carbon decreased with an increase of soil depth, and organic carbon content in the 0-40 cm soil layer was alfalfa/ryegrass mixed-sowing > alfalfa single-sowing > ryegrass single-sowing > wasteland. Also, a two-sided test for pears showed a highly significant correlation (P < 0.01) to total organic carbon and active organic carbon(r=0.975), active organic carbon and humus carbon(r=0.975), and total organic carbon and humus carbon (r=0.954); and fractal dimension values were highly significant (P < 0.01) and positively correlated to small-particle size aggregates (< 0.25 mm) for both dry-sieving aggregates (r=0.972) and water-stable aggregates (r=0.980). In conclusion, compared to wasteland, the distribution of soil aggregates was greatly changed and soil carbon sequestration was promoted after artificial grassland was planted with alfalfa/ryegrass mixed-sowing being the best planting pattern.
Soil organic carbon (SOC) affects the balance of the global climate ecosystem and is of great importance in guiding global climate change. To understand the effect of urban forest types on soil carbon content and density on the urban ecosystem, samples of soil profiles under seven types of forestry were collected from Shanghai City. The distribution of organic carbon content and density in different forests and different soil layers (0-10, 10-30, and 30-100 cm) were analyzed, and the relationships between SOC content and soil physicochemical properties by the Pearson Correlation analysis and stepwise elimination regression method was discussed. Results showed that:The average SOC content of 1 m-depth soil in Shanghai forests showed that other soft broadleaf forest > Cinnamomum camphora forest > economic forest > broadleaf mixed forest > Metasequoia glyptostroboides forest > coniferous and broadleaf mixed forest>other hard broadleaf forest, while the organic carbon density of 1 m-depth soil in Shanghai forests showed Cinnamomum camphora forest > other soft broadleaf forest > economic forest > broadleaf mixed forest > coniferous and broadleaf mixed forest > Metasequoia glyptostroboides forest>other hard broadleaf forest. SOC content in the 0-10 cm layer was significantly different from the 10-30 cm layer depending on vegetation types (P < 0.05). The average SOC content and density per 10 cm layer thickness gradually decreased in the profile, except for the economic forest. The main controlling factor for the change of SOC content in the camphor forest, other soft broadleaf forest, other hard broadleaf forest, and coniferous broadleaf mixed forest was hydrolyzed nitrogen. The main influencing factor of SOC content in the broadleaf mixed forest, and Metasequoia glyptostroboides forest was total nitrogen.
Taking 3A scenic villages in Zhejiang Province as research samples, this study explores the spatial distribution of Zhejiang Province's 3A scenic villages and its influencing factors by using the average nearest neighbor analysis, kernel density estimation, buffer analysis, geographic concentration index, imbalance index, scale index and Lorenz Curve. The results show that, at the provincial level, the spatial distribution of Zhejiang's 3A scenic villages is agglomerated with multi-central agglomerations and group distribution patterns. The 3A scenic villages in northeast Zhejiang are more agglomerated than and outnumbered those in the southwest. More than 50 per cent of Zhejiang's 3A scenic villages are located in Hangzhou, Shaoxing, Quzhou and Ningbo. At the municipal level, most 3A scenic villages are evenly distributed, and only those in three cities including Hangzhou, Quzhou and Taizhou are agglomerated. The study further indicates that the spatial distribution of 3A scenic villages in Zhejiang Province is affected by multiple factors, including regional central city, traffic conditions, natural geographical environment, and the economic development level. Finally, this paper proposes some suggestions to improve the spatial layout of 3A scenic villages in Zhejiang from the perspective of spatial structure and quantity, economic, and traffic which could provide a scientific basis for the rational construction of 3A scenic villages in Zhejiang.
To scientifically and reasonably carry out forest management and to improve quality and benefits of the forest ecosystem for a Cunninghamia lanceolata forest, one of the main forest types in Zhejiang Province, this research was conducted based on data from the national forest inventory of Zhejiang Province from 1994 to 2009. The method of variable biomass expansion factor function (BEFF) was used to estimate productivity. According to the principle of average division, longitude, latitude and altitude were divided into several half-degree zones respectively called Gradient Zones. Least-Significant Difference (LSD) was used to estimate significant differences and then analyse geographic differentiation characteristics and rules of productivity for C. lanceolata forests in three dimensions:longitude, latitude, and altitude. Results showed that productivity of C. lanceolata forests in Zhejiang Province along the longitudinal direction had significant differences (P < 0.05). Productivity in Gradient Zones Ⅰ and Ⅱ were obviously higher than productivity in other gradient zones, and differences among other gradient zones were not significant (P>0.05). Along the latitudinal direction, there were no significant differences (P>0.05) for productivity in zones, but the law of productivity fluctuation in gradient zones was consistent. In the altitudinal direction there were no significant differences (P>0.05) for productivity in Zones. As time went on, productivity of Gradient Zone Ⅴ was higher than productivity in Gradient Zones Ⅰ-Ⅳ. Generally speaking, then, productivity of C. lanceolata forests in Zhejiang Province had differentiation in the longitudinal direction but not in latitudinal and altitudinal directions; however, over time, differentiation was noticeable. C. lanceolata forests in Zhejiang Province cultivated in longitude 118°-119°E would have higher productivity.
Due to poor management, the competition intensity of Pinus tabuliformis plantations of Beijing region are generally strong, which leads to low stand quality. Therefore, scientific management is urgently needed to improve stand competition and stand quality. To provide a basis and theoretical support for scientific management of P. tabuliformis plantations in the Beijing region, an optimal competition index was determined from typical P. tabuliformis plantations in Beijing. A 100 m×100 m sample plot of typical P. tabuliformis plantation was set up in Jiulong Mountains, with 1 054 P. tabuliformis objective trees and 4 216 competitive trees in the sample plot as the research objects. A biomass regression analysis was used with competition indexes of Hegyi, CIOi, and angle-based (d_α_CIi). The optimum competitive index was selected by regression analysis and k-fold cross-validation; Kruskal-Wallis test was used to analyze the competition index of P. tabuliformis with different diameter at breast height (DBH) class size in the sample plot. Results showed that the diameter distribution of P. tabuliformis had a slightly positive normal distribution with 88.24% of the individuals distributed in the 10-25 cm diameter range. P. tabuliformis biomass obeyed the power function relation with (d_α_CIi) and Hegyi competition indexes, and obeyed the exponential function relation with CIOi. The coefficient of determination (R2), and 10 times of 10-fold cross-validation R2 values of (d_α_CIi) were highest (R2 is 0.770 5 and 0.769 5, respectively), and the loss of R2 was smallest (R2=0.001 0) meaning the quantization effect was (d_α_CIi) > Hegyi > CIOi. The competition index gradually decreased with an increase in DBH, and the proportion of over shading of the competition index also gradually decreased or stayed the same. When DBH was not less than 20 cm (about 1/4 of the total), the change in competition index did not vary (P>0.05)with an increase in class size. Competition was mainly intraspecific accounting for 93.64% of the total competition intensity. The quantity and competition intensity of intraspecific competition trees increased first and then decreased with diameter class. However, on the whole, the number and competition intensity of interspecific competition trees decreased first and then increased with the diameter class. Thus, (d_α_CIi) could better quantify competition intensity of typical P. tabuliformis plantations in Beijing; intraspecific competition was greater than interspecific competition with vertical spatial segregation within and between species being important conditions for species coexistence; and according to the spatial distribution of competition indexes for P. tabuliformis, reasonable thinning of individuals with a DBH less than 20 cm could improve forest structure.
To understand the influence of disturbance to the hydrological and ecological functions of litter in a Pinus sylvestris var. mongolica sandy-fixation plantation, the combined methods of field investigation and a water holding experiment were conducted. Two sites of 37 and 46 year old P. sylvestris var. mongolica sandy-fixation plantations having disturbance conditions in Zhanggutai and two with enclosed conditions having the same site conditions but without disturbance, as a control, were selected. The amount, water holding capacity, water holding rate, and water absorption rate of litter, as well as their responses to long-term disturbance on different types of litter were determined. The statistic data of litter characteristics were analyzed using ANOVA and LSD. Results showed that plantations with disturbance had coverage of 60%-85%, thickness of 0.4-1.4 cm, and litter amount of 1.8-2.8 t·hm-2, which were significantly less than the control (P < 0.001). The maximum water holding capacity for different types of litter on plantations with disturbance were significantly less than the control (P < 0.05), varying from (0.24±0.04) t·hm-2 to (15.02±3.56) t·hm-2. The maximum water holding rate of different types of litter on disturbed plantations was in the order of herb > pine needle > others; whereas, the control plantation was in the order of herb > others > pine needle. Generally, the water holding processes of different types of litter increased sharply in the preliminary stage and then tended to slow. The water absorption rate for herb was obviously higher than those of pine needle and others during the first two hours. The water absorption rate of herbs was also higher in disturbed plantations than in the control. The water absorption rate of pine needle always was lower than that of others under disturbed plantation, while the water absorption rate performed the opposite regime under disturbed plantation. In conclusion, P. sylvestris var. mongolica sandy-fixation plantations required urgent management and governance due to long-term disturbances of pine needle collection and grazing that not only reduced litter, but also changed litter type composition directly or influenced the community vegetation characteristics indirectly, thereby influencing litter water holding capacity.
In order to protect local ecological resources contrapuntally, an important forest composition tree species Phoebe sheareri, its basic community characteristics was determined. Ten 20 m×20 m plots were delineated on the northern slope of Baohuashan in Jiangsu Province by the sampling method and then studied using plant community characteristics and diversity analysis. Results of this community showed that there were 120 species of vascular plants belonging to 100 genera of 59 families including 115 species of angiosperms belonging to 95 genera of 55 families and 5 species of pteridophytes belonging to 5 genera of 4 families. The floristic types of seed plants in the sample plots were dominant at the level of genera with the obvious characteristics of transition from subtropical to warm temperate components. Vertical structure of the community was clear, and the dominant species with their importance values were P. sheareri (29.69), Liquidambar formosana (10.34), Cyclobalanopsis glauca (8.61), Acer henryi (7.83), and Meliosma oldhamii (6.12). The dominant species in the shrub layer was P. sheareri, with an importance value of 34.00, and the dominant species in the herb layer was Cardamine anhuiensis with an importance value of 10.52. Distribution regularity of each frequency class for the community was A > B > E > D > C indicating a relatively stable community. Age structure analysis of the dominant population, showed that the evergreen species P. sheareri and C. glauca were growth-type populations, deciduous L. formosana and M. oldhamii were decline-type populations, and C. glauca was a stable-type population indicating that the community was in the middle stages of development. Community diversity indexes revealed an overall high level of community species diversity, but a low functional diversity. Single species occupied the larger niche of the community, and the effective resource utilization rate of each species in the community was low. Thus, the P. sheareri community was temporarily stable, but intra-species competition of dominant populations could subsequently aggravate pressure on environmental resources making it advisable to fell the disadvantaged trees and strengthen in-situ protection of the community.
In order to have a more comprehensive understanding of the structural change and succession process of plant community in Haikou City, and predict the composition of its future change trend. A total of 235 randomly selected urban forest plots were studied in a built-up area of Haikou City. Structural characteristics and their corresponding plant diversity indexes were determined with a correlation analysis. Results indicated that (1) The presence of 283 species of common plants in the built-up area belonging to 218 genera of 72 families with 114 native species and 169 exotic species. (2) The dominant plants included Cocos nucifera, Pterocarpus indicus, Roystonea regia, and Ficus benjamina. (3) The diameter presented a distribution pattern of "overall small", and the overall tree height was low with an average height of 6.8 m. (4) There was a significant correlation between species diversity and functional diversity indexes (P < 0.05). (5) Also, the phylogenetic diversity index (PD) was significantly correlated (P < 0.05) with species diversity indexes in the tree layer and herb layer. The phylogenetic species variability index (PSV) was not correlated with most species diversity indexes and functional diversity indexes, but the phylogenetic species variability evenness (PSE) index was significantly correlated with most of them (P < 0.05). Haikou City having a large improvement potential in forest development, should avoid the homogeneity phenomenon where native species have been adopted in urban forest development; to ensure comprehensiveness and accuracy, Haikou should consider multi-level and targeted diversity indexes and functional trait parameters when evaluating urban plant diversity.
Understory vegetation, representing the main component of biodiversity in a forest community and playing a key role in forest functioning and canopy structure, are important characteristics of a forest community. To evaluate the effects of different gradients of canopy structure on understory vegetation, secondary evergreen broadleaf forest communities in the suburbs of the Pearl River Delta were studied. The effect on understory plants was tested using classical community survey methods and hemispherical photography. Analysis included use of Cluster Analysis, Non-parametric Test (Kruskal-Wallis test), Indicator Species Analysis (ISA), and Canonical Correspondence Analysis (CCA). Results showed that (1) Canopy structure and understory light conditions varied along the canopy gradient. The standing density and average diameter at breast height (DBH) showed a highly significant difference (P < 0.001); whereas, the transmitted direct light, transmitted diffused light, and transmitted total light significantly differed along the canopy gradient (P < 0.05). (2) The understory vegetation was rich; and the abundance and average height as well as total coverage, significantly differed with canopy gradient (P < 0.05). Species were richest in canopy gradient 2, but the average height and total coverage were both highest in canopy gradient 3. (3) The responses of understory vegetation to canopy structure and transmitted light varied. Wendlandia uvariifolia and Ilex viridis were both indicator species of transmitted direct light and transmitted total light. (4) The CCA showed that canopy structure and understory light conditions affected the distribution of understory vegetation. Ferns such as Adiantum flabellulatum, Blechnum orientale, Dicranopteris dichotoma, and Woodwardia japonica resided in areas of weak sunlight, but heliophytes like Camellia oleifera and Tetracera sarmentosa inhabited places where they received better light. Moreover, distribution of neutral plants like Schima superba and Ardisia lindleyana were more affected by the height and DBH of standing trees. This study demonstrated that understory vegetation varied according to understory light conditions along the canopy gradient with transmitted total light and transmitted diffused light being the main factors influencing the understory light environment of the secondary evergreen broadleaf forest.
To clarify changes in composition of mineral elements, oil content, and fatty acid content of kernels during maturity of the hickory (Carya cathayensis) nut, the contents of N, P, K, Ca, and Mg in kernels and pericarps, as well as oil content and fatty acid composition of kernels during the late development and maturation periods of fruits with 40-year-old mature hickory trees were measured. A correlation analysis of these components was also conducted. Results showed that during the maturity period (from August 5th to September 6th), dry matter of total fruits did not increase (P>0.05). The fast accumulation phase of the kernel was from August 5th to August 20th with dry matter of the kernel increasing 116.1% from 0.62 g per nut to 1.34 g per nut), and an amount of organic matter was transferred from the pericarp to the kernel. K was transferred from kernel to pericarp with K in kernels decreasing from August 5th to September 6th from 11.71 mg·kg-1 to 3.44 mg·kg-1; whereas, in pericarps it was increasing from 5.70 mg·kg-1 to 9.18 mg·kg-1(P < 0.05). Contents of N, P, and Mg in the kernel was higher than the pericarp. Contents of the main mineral elements in the kernel and pericarp had some correlation. Total oil content increased quickly and then slowed during maturity with the fast accumulation phase from August 5th to August 20th where total oil content went from 243.20 mg·g-1 to 586.02 mg·g-1(P < 0.05). Oleic, linoleic, and palmitic were the main fatty acids comprising approximately 92.33% to 97.50% of the total fatty acids in the kernel. The oil content was significantly and positively correlated with the contents of palmitic (r=-0.855, P < 0.01) and linolenic (r=-0.931, P < 0.01), and was significantly correlated with the content of oleic (r=0.783, P < 0.05). Fatty acids which had near or the same number of carbons tended to have a highly positive correlation. The content of oleic was also significantly and positively correlated with the content of linoleic (r=-0.966, P < 0.01) and linolenic (r=-0.854, P < 0.01). In general, N and K were the key mineral elements for fruit development, N and K contents in the kernel had a high correlation to fatty acid compounds, and it was a suggested that fertilizing in the early kernel filling period was key to achieving high yield and high quality cultivation.
Jingfan 302 in nutrient film technique, which was seclected as the research object, was set with four different treatments:the Japanese Garden Test (1.0 time), the Japanese Garden Test (2.0 times), the Japanese Garden Test adding CaCl2·2H2O (1.0 time), and the Japanese Garden Test (1.5 times). On this basis, various mineral absorption and proportion of different parts of tomato plant, quantity and yield for different treatments were compared and analyzed to screen out the most suitable nutrient solution formula. Results showed that the Japanese Garden Test adding CaCl2·2H2O (1.0 time) significantly promoted (P < 0.05) stem growth of tomato plants, and compared to the other treatments, increased (P < 0.05) dry matter quality as well as accumulation of mineral elements in tomato organs. Accumulation of the mineral elements K, N, and Ca in the plants was much higher than (P < 0.05) Na, Mg, and P. The content of elements in the leaf, stem, and petiole were more than (P < 0.05) the fruit stalk and roots. Nitrogen was mainly distributed to the fruit stalk, P and Na to the roots and stems, and Ca and Mg to the leaves, stems, and roots. The Japanese Garden Test with CaCl2·2H2O (1.0 time) increased (P < 0.05) individual yield 4%-13%. Overall, the Japanese Garden Test with CaCl2·2H2O (1.0 time) treatment not only increased dry matter quality of the plant parts and promoted accumulation of mineral elements, but also increased the yield and flavor of tomatoes using nutrient film technique.
Drawing on the survey data of 245 farmer households in Zhejiang Province, this paper uses the Stochastic Frontier Approach (SFA) to measure the technical efficiency of the sample farmers' forestry management, and analyze the influencing factors of the technical efficiency, in particular the impact of labor quality of hired forestry labor on the technical efficiency of farmer's forest management. Results show that the average technical efficiency of farmer's forestry management in sample area is 0.57, and there is obvious loss of technical efficiency. The average technical efficiency of farmer households with hired labor is 0.59, and that of households without hired labor is 0.76. It shows that hiring labor in the process of farmer's forestry production will hinder the improvement of technical efficiency of farmer's forestry management and have a negative impact on the forestry production. Empirical analysis shows that hiring labor in the process of farmer's forestry production does have a negative impact on the forestation, and the different quality of the hired labor has different impact on improving the technical efficiency of farmer's forestry management:the greater the proportion of hired workers in the total labor input of forestry production, the greater the negative impact on improving the technical efficiency of farmers' forestry management will be. Based on the research findings, suggestions on promoting moderate scale operation, increasing investment in science and technology services, and establishing effective labor supervision and manage mechanism are proposed.
To invert the fractional vegetation coverage (FVC) of Fuzhou City, and to analyze the influences of topographic factors on the temporal and spatial characteristics of fractional vegetation coverage, we selected six periods of Landsat TM/OLI remote sensing image data with a 30 m spatial resolution from 1995 to 2015. The improved pixel binary model and deviation claculation method were used to analyse temporal and spatial characteristics of FVC. The results indicated that (1) The FVC values of Fuzhou City increased from 57.93% (1995) to 66.44% (2015) for an average annual increase of 0.43%. There were differences in the trends of FVC change among the different degree of FVC, and the area of extremely high FVC had a gradually increasing trend and its area accounted for 54.18% in 2015. Overall, the improved FVC area accounted for 55.73% of Fuzhou City, but the degraded FVC area was still approximately 16.98% and vegetation restoration was needed. (2) Elevation and slope gradient had a strong influence on the temporal and spatial pattern of FVC in Fuzhou City. FVC increased with increasing elevation, and firstly increased but then decreased slightly with increasing slope gradient. There were no differences in FVC among slope directions except a slightly lower FVC at the flat slope. (3) From 1995 to 2015, the FVC had increasing trends at elevation > 300 m and slope > 5°, whereas the FVC of low elevation and flat slope had litter changes, and the changes of FVC at each slope directions were same. Thus, the topographic factors had a strong impact on the temporal and spatial patterns of FVC in Fuzhou City.
The ecological effect of the Grain for Green Project in the alpine loess area of Qinghai, affected the health status of water conservation forests. However, there is a lack of scientific evaluation method in this area present. This study was aimed to identify the key environmental factors affected the forest and find suitable vegetation types by making health evaluation on water conservation forests. Five typical water conservation forests, including Picea crassifolia, Larix principis-rupprechtii, Betula platyphylla, Picea crassifolia-Larix principis-rupprechtii, and Picea crassifolia-Betula platyphylla, in the Taergou Forest Farm of Datong County were taken as research objects. Three standard samples (20 m×20 m) were selected in every stand for plant (trees, shrubs and herbs) investigation and soil properties measurement. The theory of forest health, combined with expert consultation were used along with the entropy weight method to construct the forest health evaluation index system. The health status of these five forests were evaluated and analyzed by the integrated health index. Results showed that P. crassifolia-B. platyphylla was a high quality forest, B. platyphylla was a healthy forest, P. crassifolia and P. crassifolia-L. principis-rupprechtii were fairly healthy forests, and L. principis-rupprechtii was an unhealthy forest. In the health evaluation index system, the three most important indexes, or critical factors affecting forest health, and their weights, were forest fire risk rating (0.242 3), leaf area index (0.128 8), and degree of pests and disease (0.122 2). Generally, the health of a mixed forest was better than a pure forest, a broadleaf forest was better than a coniferous forest, and the P. crassifolia-B. platyphylla forest was a relatively good tree species allocation model for a water conservation forest.
A new golden vicary privet (Ligustrum×vicaryi) leaf spot disease caused by Corynespora cassiicola was found in Luoyang, Henan Province. To provide basic theoretical knowledge for diagnosis and control of this disease, Corynespora cassiicola isolates collected from L.×vicaryi were investigated by morphology, biological characteristics, pathogenicity, and molecular phylogenetics. Morphological examinations were made from cultures sporulating on potato dextrose agar (PDA), as well as on host material. Diseased leaves were incubated in moist chambers to enhance sporulation for morphological observations. The effects of temperature, pH, and light treatment, as well as carbon and nitrogen sources on mycelial growth were determined. Pathogenicity tests were performed by inoculating detached leaves from L.×vicaryi, Cucumis sativus, Solanum lycopersicum, Capsicum annuum, and Solanum melongena using one representative isolate. Sequences of internal transcribed spacer (ITS) regions of ribosomal DNA (rDNA), the β-tubulin (tub 2) gene, and the translation elongation factor 1α (ef-1α) gene were amplified, sequenced, and blasted in GenBank. Phylogenetic analysis was performed with the concatenated sequence alignment of three genes, (ITS, tub 2, and ef-1α) using MEGA 6.0 software. A multilocus phylogenetic tree was obtained using neighbor-joining analysis. Results showed variations in morphology among origin of the conidia of C. cassiicola. Compared to those on PDA, conidia obtained from infected leaves had higher numbers of pseudosepta, and were longer. Biological characteristics analysis showed that the fungus grew at temperatures ranging from 10℃ to 40℃ with optimum growth at 25℃ (P < 0.05) and no growth being observed at 5℃. The fungus grew at pH 4-11 and optimum growth was observed at pH 6-8. The light period of 12 h (light)/12 h (dark) promoted mycelial growth of C. cassiicola compared with dark treatment of all 24 h (P < 0.05). Maltose supplemented media showed maximum growth among the tested carbon sources (P < 0.05). Among several nitrogen sources tested, peptone and yeast extract paste were found superior for growth (P < 0.05). Pathogenicity tests revealed that the isolates from L.×vicaryi could infect L.×vicaryi, C. sativus, S. lycopersicum, C. annuum, and S. melongena, and that there were differences in the time of appearance and size of lesions according to the hosts. Ligustrum×vicaryi was most susceptible to the isolates that originated from L.×vicaryi. The phylogenetic tree showed that the three isolates of C. cassiicola from L.×vicaryi and all the isolates from C. sativus could be put into one clade (bootstrap value of 100%). These analyses showed that the phylogenetic lineages among the tested isolates correlated with host of origin and pathogenicity.
The lipopeptide produced by Bacillus amyloliquefaciens has a variety of biological activities such as antibacterial, anti-tumor, and anti-virus; however, its production is generally very low. To explore better fermentation conditions so as to gain more lipopeptide with easy and fast evaluation methods for lipopeptide production that would greatly improve work efficiency, the yield of crude lipopeptide based on the difference of total organic carbon (TOC) in a liquid before and after lipopeptide separation was calculated using the acid deposition approach. First, optimal fermentation time for producing lipopeptide by pathogen inhibiting culture on plates containing a fermentation liquid was determined. Then, a liquid medium with pH 5, 6, and 7, for producing different concentrations of lipopeptide, was prepared. Also, CO2 emission rates for microbial activity in the pH 6 and 7 treatments were measured. Results showed that 72 hours was the optimal fermentation time. The crude yield of lipopeptide calculated from the difference of TOC in liquid before and after lipopeptide separation was positive compared to traditional weight methods with the coefficient being 0.563 2 (n=9). For both methods, pH 6 > pH 7 > pH 5. However, for the same pH of the liquid medium, crude yield was lower with weight methods than the TOC difference methods. Lipopeptide production efficiency and CO2 emissions rate with the WK1 strain were lowest for the pH 5 treatment. However, crude yield of lipopeptide (in a 1 228 mg·L-1 medium) and lipopeptide production efficiency (in a 234 mg·kg-1 OC medium) were highest at pH 6. Thus, the TOC difference method was an easy and fast method for lipopeptide production evaluation.
To enhance studies on genetic diversity and molecular assistance breeding of Rhododendron fortunei, one of the native Rhododendron species in China with a high horticultural and ornamental value, the transcriptome of R. fortunei was sequenced using Illumina technology. In addition, sequence assembly, public databases, Gene Ontology (GO) analysis, Eukaryotic Orthologous Groups (KOG), Kyoto Encyclopedia of Genes and Genomes (KEGG), and MADS-box transcription factor were used. Results of the sequence assembly obtained 84 633 unigenes with a mean length of 691.4 bp. Public databases were successfully searched annotating 35 526 unigenes, and GO analysis showed that 23 215 unigenes were potentially involved in 55 functional categories of biological processes, cellular components, and molecular functions. The KOG analysis indicated 11 085 unigenes classified into 26 functional groups; whereas, the KEGG analysis assigned 9 887 unigenes to 272 known pathways. Also, 24 unigenes were identified to encode MADS-box transcription factor belonging to 10 different subfamilies. In addition, 21 900 simple sequence repeat (SSR) loci were determined in the transcriptome of R. fortunei. In conclusion, this study could provide an important foundation for genetic diversity analysis, marker development, molecular assistant breeding, and functional gene isolation in R. fortunei, as well as future SSR marker development.
This study was conducted to determine the photo-response and chlorophyll fluorescence parameters of potted Dicranopteris dichotoma for different light intensities and nitrogen application. Using one of the "marker species" of degraded vegetation in subtropical forests as the research material. Pot experiment were conducted to design with six treatments of different light intensities, including transmittance 35.96% (L1), 13.00% (L2) and 4.75% (L3), and nitrogen level, including nitrogen (N1) and without nitrogen (N0). All-light was used as control. The photosynthetic-light curve, photosynthetic characteristic parameters, gas-exchange, chlorophyll a fluorescence parameters and photosynthetic pigments were measured three times for each treatment. Results showed that:(1) Without nitrogen application, for L2, Pnmax and PLS were highest; PLC, Rd, and AQY were least. (2) For N0 application, the order of Pn and AQY was L2 > L1 > ck > L3, Gs was L1 > ck>L3 > L2; for N1 application the order of Pn, AQY and Gs was L1 > L2 > L3. For N1 and N0, the order of Ci was ck > L1 > L2 > L3. (3) For N0, under L2 and L3 light intensity, chlorophyll a, chlorophyll b, total chlorophyll content and carotenoids were significantly higher than those under L1 and ck(P < 0.05), and the overall performance increased with the decrease of light intensity. Chlorophyll a/b significantly decreased with a decrease in light intensity (P < 0.05). For the same light intensity, the content of photosynthetic pigments in the N application group was significantly higher than that in the non-N application group under L1 light intensity(P < 0.05), and significantly higher than that in other treatments(P < 0.05). (4) Except for L1 in N0 group, Fo and Fm under other light intensities were significantly different and increased with the decrease of light intensity(P < 0.05), the Fv/Fm of ck was significantly lower than that of other light intensities(P < 0.05). Compared with the N0 group, Fo decreased significantly, Fm of L3 decreased significantly, Fv/Fo and Piabs of L2 increased significantly(P < 0.05). In a word, under full light, the photos-inhibition of potted D. dichotoma is the most serious. N can improved the net photosynthetic rate of potted D. dichotoma to a certain extent, increased heat dissipation and alleviated the photo-inhibition, but it is not conducive to the improvement of photosynthetic pigments of L2 and L3.
GRAS is a very important transcription factors (TFs) family in plants and can be classified into ten subfamilies. There has been numerous research on elucidating the functions of GRAS TFs in medical plants and other plants. The existing research indicates that this kind of TFs participate extensively in the process of growth, development, response to abiotic stress, signal transduction, primary and secondary metabolism, and so on. This study reviews the research progresses on GRAS TFs around the structure features, functional roles, and new research advances. After analyzing the research prospect of medicinal plants in combination with our own research, the paper proposes the following directions for future research:firstly, the function of each GRAS subfamily conserved structural domain should be analyzed; secondly, the evolution characteristics of GRAS protein N-terminal variable sequences should be elucidated; thirdly, the molecular regulatory network about how the GRAS families regulate the quality and respond to adversity stress should be analyzed; finally, the cooperative regulation model of epigenetic modification and GRAS should be studied. This study provides an important reference to conduct innovative research works on Chinese medical plants.
Simple sequence repeat (SSR) molecular markers in the chloroplast genome can be used for germplasm resource identification and population genetic structural analysis at a higher classification level due to the chloroplast genome being of maternal inheritance and high conservation. To screen and develop SSR markers which will be useful for genetic diversity analysis, fingerprinting and germplasms resource identification in the chloroplast genome of Zanthoxylum bungeanum, a traditional spice plant in China, TRF software and SSR Hunter were used to screen the mono-, di-, tri- and tetra-nucleotide repeat motifs and 16 germplasms of Zanthoxylum including 10 individuals of Z. bungeanum, 5 individuals of Zanthoxylum armatum, and 1 individual of Zanthoxylum piperitum were selected to test polymorphism of these detected loci. As a result, 144 SSR loci were identified with an average distribution distance of 1 100.00 bp in the chloroplast genome of Z. bungeanum. Based on parameters set by the detection software, mono-nucleotide and tri-nucleotide repeat motifs were the main repeat types accounting for 91.67% of the total. In addition, 30 SSR primer pairs were randomly designed and synthesized with 10 of them showing polymorphism. The polymorphic markers of mono-nucleotide repeat motifs were more than that of polynucleotide repeat motifs in this study. Furthermore, these cpSSR markers could effectively divide Z. bungeanum, Z. armatum, and Z. piperitum, but no polymorphic marker was found in the 10 individuals of Z. bungeanum. Thus, cpSSR markers of Z. bungeanum could be used for genetic diversity analysis among different interspecies of Zanthoxylum.
The compound of a hybrid polyketide/nonribosomal peptide, which usually has some particular bioactive activity, is catalyzed by an enzyme of hybrid PKS/NRPS. A hybrid PKS/NRPS containing a SDR domain from Beauveria bassiana has not yet clearly elucidated. To inveastigate this type of gene, the present study obtained a hybrid PKS/NRPS gene (named Bbpks2) from B. bassiana using genome-mining, predicted its gene function with a bioinformatic analysis, and detected the expression level of Bbpks2 in the medium by adding 7 carbon additives(adding 4.0 g·L-1 of every carbon additives) using 6.0 g·L-1 malt extract and 3.0 g·L-1 yeast extract as basic medium, or 4 nitrogen additives(adding 4.0 g·L-1 of every carbon additives) using 1.8 g·L-1 maltose and 6.0 g·L-1 as basic medium, 3 replications every treatment. Results showed that the Bbpks2 gene had 12 051 bp, encoded 4 016 amino acids, and had a sequential domain organization of KS-AT-DH-MT-KR-ACP-C-A-PP-SDR. The proteins of BbPKS2 could belong to a hybrid PKS/NRPS, which was comprised of a short-chain dehydrogenase reductase (SDR) domain. BbPKS2, PMB64475.1 from the strain of B. bassiana JEF007, and PNY25600.1 from Tolypocladium capitatum were three hybrid PKS/NRPS proteins that clustered in the same clade meaning that BbPKS2 could take part in the biosynthesis of a compound belonging to the hybrid polyketides/nonribosomal peptides. Comparing the expression level of the Bbpks2 gene when appending different C or N additives, the expression level of the Bbpks2 gene with lactose added to the basic medium was found to be at least 3.4 times higher than the other C additives, and beef extract 1.3 times higher than the other N additives. The present study could provide some help in further identifying the specific function of the Bbpks2 gene through heterologous expression and could provide a basis for explaining the molecular regulation mechanism when utilizing the gene resource of B. bassiana.
To promote the process of vegetation restoration due to rocky desertification in southwest China, Fraxinus malacophylla, a native species in southwest China, has been widely used in local vegetation restoration projects. To determine its response to different soil moisture conditions, one-year-old F. malacophylla seedlings were used in a pot experiment to study responses to different soil moisture conditions. The biomass, net photosynthetic rate, stomatal conductance, intercellular carbon dioxide concentration, and transpiration rate were measured for five soil moisture conditions:40%, 34%, 28%, 22%, and 16% split-plot design with treatments of W1, W2, W3, W4, W5 and 10 replications. The growth characteristic of seedings was measured by steel tape and balance while the photosynthetic characteristic was measured by Li-6400. Results showed that (1) F. malacophylla seedlings could survive in the five soil moisture conditions. The optimum soil moisture treatment for seedling growth was 28% with a total seedling biomass of 17.16 g. When water conditions were excessive or inadequate, growth and photosynthesis of F. malacophylla seedlings decreased (P < 0.05). (2) When soil moisture was < 28%, biomass was preferentially allocated to root growth to help in adapting to a drought environment, and when soil moisture was 16%, root biomass was over 50%. With low soil moisture, F. malacophylla improved its drought resistance by closing some stomata to ensure normal photosynthesis. Also, when soil moisture was 16%, drought stress reduced the photosynthetic capacity resulting in a significant decrease in total biomass, net photosynthetic rate, and water use efficiency (P < 0.05). (3) When the soil moisture condition was 34% and 40%, root growth of F. malacophylla was hindered leading to a strong decrease in aboveground biomass and net photosynthetic rate (P < 0.05). (4) Except for the 16% soil moisture treatment, water use efficiency of F. malacophylla with the different soil moisture conditions was>2.40 mmol·mol-1. Thus, F. malacophylla could adapt to the uneven spatial and temporal distribution of soil moisture in the southwest karst region, but drainage and water logging prevention were necessary during the rainy season.