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, Available online doi: 10.11833/j.issn.2095-0756.20230583
Abstract:
Objective The objective is to explore the relationship between the content and accumulation of mineral elements in the branch-leaf mixture and seeds of Torreya grandis ‘Merrillii’ during the early growth stage of seeds, in order to provide a basis for scientific fertilization and improve the quality and yield of T. grandis ‘Merrillii’ seeds. Method (2+17) a T. grandis ‘Merrillii’ trees (2 a rootstocks and 17 a after grafting) were selected for experiment on Donghu campus of Zhejiang A&F University. Lateral branches (with leaves) and seeds of the second generation were collected from early March to early July, and the dynamic changes in nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), zinc (Zn), manganese (Mn) and copper (Cu) content and accumulation in branch-leaf mixture and seeds were analyzed. Result In the early growth stage of T. grandis ‘Merrillii’ seeds, there was no significant change in the transverse and longitudinal diameter of the seeds, dry and fresh weight, and moisture content of each fruit before early April. However, from mid April to mid June, the growth rate increased rapidly and then stabilized, and the accumulation of N, P, and K in branch-leaf mixture decreased while the accumulation and content of N, P, and K in seeds continued to increase, which indicated that N, P, and K in branch-leaf mixture were preferentially supplied to the growth of seeds. During the slow growth and flower bud differentiation stage, the demand for N, P, and K by seeds was relatively small, while during the rapid growth stage, the demand for N, P, and K by seeds increased. This phenomenon intensified with time. On a time scale, Ca gradually absorbed and accumulated in the branch-leaf mixture, while Ca content and accumulation in seeds decreased and ertremely decreased significantly. After the rapid growth period, the accumulation of Mg in seeds increased, while the accumulation and content of Mg in branch-leaf mixture decreased with the expansion of seeds. During the early growth stage of T. grandis ‘Merrillii’ seeds, the accumulation of Zn and Cu in branch-leaf mixture showed a decreasing trend, and the seed had a relatively small demand for Zn, Cu and Mn. Conclusion (1) The volume and moisture content of the fast-growing T. grandis ‘Merrillii’ seeds increase rapidly, and tend to stabilize after the filling period. (2) The content and accumulation of elements are closely related to the long-term growth of T. grandis ‘Merrillii’ seeds. To improve the quality of seeds, N, P and K fertilizers should be applied at the end of the slow growth period and the beginning of the fast growth period, along with an appropriate amount of trace element fertilizers such as Zn and Cu. Mg fertilizer should be applied after seed harvest. [Ch, 5 fig. 27 ref.]
, Available online doi: 10.11833/j.issn.2095-0756.20230584
Abstract:
Objective Soil heavy metal pollution is a common problem encountered in agricultural production activities, and how to effectively and synchronously passivate arsenic and lead in soil has become a research hotspot. Method Raw biochar was prepared from rice husks, and manganese-modified biochar was obtained through potassium permanganate. Pot experiments were conducted using garlic (Allium sativum) as an indicator plant to evaluate the effects of raw biochar and manganese-modified biochar at different application rates (10 and 30 g·kg−1) on the bioavailability of arsenic and lead in soil and soil enzyme activities. Result The application of different proportions and types of biochar significantly increased the content and pH of soil organic matter, available potassium and available phosphorus (P＜0.05), while decreased the content of soil alkaline hydrolyzed nitrogen. The effect of manganese-modified biochar was more significant than that of original biochar. The application of 10 g·kg−1 manganese-modified biochar significantly reduced the content of available arsenic in soil by 11.5%, while 30 g·kg−1 manganese-modified biochar significantly decreased the content of lead in the extractable state of diethylenetriamine pentaacetic acid (DTPA) in soil by 28.3%. Compared with the control, the application of 10 g·kg−1 manganese-modified biochar increased the activities of β-N-acetylglucosamine glycase by 11.6%, and the application of 30 g·kg−1 manganese-modified biochar significantly increased the activity of acid phosphatase and β-glucoglycase by 9.8% and 37.7%, respectively. Meanwhile, the contents of nitrogen, phosphorus and potassium in garlic plants treated with manganese-modified biochar significantly increased (P＜0.05), while the contents of arsenic and lead significantly decreased (P＜0.05). Conclusion Manganese-modified biochar has significant potential in improving soil fertility and repairing arsenic-lead contaminated soil. [Ch, 8 fig. 1 tab. 52 ref.]
, Available online doi: 10.11833/j.issn.2095-0756.20240256
Abstract:
Objective The impact of different drying methods on the quality of dried Prunus mume flowers is to be studied and evaluated, so as to provide reference for maintaining the quality of dried P. mume flowers in drying process. Method 4 different drying methods (hot air drying, microwave drying, compound drying and vacuum freeze-drying) were used to treat 8 P. mume flower cultivars (‘Dongfang Zhusha’ ‘Guhong Zhusha’ ‘Xiaohong Gongfen’ ‘Fenpi Gongfen’ ‘Fentai Yudie’ ‘Yueguang Yudie’ ‘Jiuguang Lve’ and ‘Suyu Lv’). Color difference, antioxidant capacity, and total flavonoid content were used as evaluation indicators to compare the impact of different drying methods on the quality of P. mume flowers. The entropy weight-coefficient of variation method was used for combined weighting to calculate the comprehensive score. The evaluation model was verified by the weighted proximation ideal solution sorting method and the optimal drying method was obtained. Result The color difference and shrinkage rate treated with vacuum freeze-drying were the smallest, less than 33.09 and 28.7%, respectively, and the total flavonoids, anthocyanins, and total chlorogenic acid mass fractions of the samples were the highest. The soluble protein mass fraction and antioxidant capacity of the materials treated with vacuum freezing and composite drying methods were the highest. The retention rate of volatile substances was the highest after composite drying, exceeding 50%. The comprehensive scores ranking from high to low was vacuum freeze-drying group, composite drying group, hot air drying group, and microwave drying group. Conclusion The mass fraction of active ingredients is the highest after vacuum freeze-drying, followed by composite drying. The quality of P. mume flowers is the best after vacuum freeze-drying and composite drying, which can be used for high-quality processing and mass production. [Ch, 8 fig. 6 tab. 29 ref.]
, Available online doi: 10.11833/j.issn.2095-0756.20240162
Abstract:
Objective The objective is to comprehensively evaluate the spatial structure of four forest types in Jinzishan state-owned forest farm in Hubei Province, and determine the main factors affecting the forest stand structure in the region, so as to provide a theoretical basis for improving sustainable forest management level and forest quality. Method Based on the measured plot data of evergreen deciduous broad-leaved mixed natural forest, Cunninghamia lanceolata plantation, Cryptomeria japonica var. sinensis plantation and Liriodendron chinense plantation, forest spatial structure indicators such as uniform angle index, neighborhood comparison, mingling degree, and crowding degree were selected, and the unit circle comprehensive evaluation system was applied to comprehensively evaluate the four typical forest types. Result The proportion of random individual trees in different types was the highest, and the proportion of trees in different neighborhood comparison degrees was similar on the whole. The overall distribution of trees in the evergreen deciduous broad-leaved mixed natural forest was random [average value of uniform angle index (\begin{document}$\bar W $\end{document} \begin{document}$\bar M $\end{document} \begin{document}$\bar U $\end{document} \begin{document}$\bar C $\end{document} \begin{document}$\bar W $\end{document} \begin{document}$\bar W $\end{document} \begin{document}$\bar C $\end{document} \begin{document}$\bar C $\end{document} \begin{document}$\bar C $\end{document} Conclusion There are differences in stand structure of different origins in the same region, and the spatial structure of evergreen deciduous broad-leaved mixed natural forest is better than that of Cunninghamia lanceolata, Cryptomeria japonica var. sinensis and L. chinense plantations. [Ch, 2 fig. 6 tab. 37 ref.]
, Available online doi: 10.11833/j.issn.2095-0756.20240141
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Objective The objective is to simulate and analyze the spatiotemporal evolution trend of forest net ecosystem productivity (NEP) in Lishui City, and reveal its response mechanism to extreme precipitation, so as to provide data support for spatiotemporal assessment of forest carbon sink potential in Lishui. Method The spatiotemporal pattern of forest NEP in Lishui from 1979 to 2079 was simulated under three climate scenarios (RCP 2.6, RCP 4.5, and RCP 8.5) by integrating plot survey, remote sensing observation and InTEC model. The spatiotemporal characteristics of extreme precipitation were analyzed and a structural equation model was constructed to explore the impact of extreme precipitation on NEP. Result (1) The frequency and intensity of extreme precipitation in Lishui during 1979－2015 showed an increasing trend. In the future climate scenario (except RCP 2.6), the extreme precipitation, frequency and intensity of RCP 4.5 and RCP 8.5 would continue to increase, with a higher trend of extreme precipitation events in areas such as Liandu District, Jinyun County and Jingning She Autonomous County. (2) Forest NEP showed an increasing trend from 1979 to 2015, with a growth rate of 20.18 g·m−2·a−1. From 2016 to 2079, forest NEP showed a downward trend under the three climate scenarios, but the total carbon sink showed an increasing trend, with the maximum NEP accumulation reaching 10.97 Pg. (3) From 1979 to 2015, extreme precipitation had positive effects on NEP, while it had negative impacts on NEP under the other two scenarios (RCP 4.5 and RCP 8.5) during 2016－2079, except for RCP 2.6 scenario under which extreme precipitation had no significant effect on NEP. However, extreme precipitation under RCP 8.5 had less impact on NEP than that under RCP 4.5. Conclusion Forests in Lishui demonstrate strong carbon sink capacity, and have high carbon sink potential under future climate scenarios. However, the impact of extreme precipitation on NEP should not be ignored. [Ch, 5 fig. 22 ref.]
, Available online doi: 10.11833/j.issn.2095-0756.20240180
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Objective This study aims to analyze the biomass distribution pattern of Eucalyptus plantations at different ages, so as to provide theoretical basis and data support for accurate assessment of carbon storage and carbon sink in China’s Eucalyptus industry. Method Eucalyptus urophylla×E. grandis plantation in Leizhou Peninsula was taken as the research object. The whole-plant harvesting method was used to measure the biomass of various organs in 57 trees aged 1, 2, 3, 6 and 10. Using diameter at breast height (DBH), height (H), and diameter at breast height-tree height (DBH 2 H and DBHH) as independent variables, allometric growth models for organ biomass, aboveground biomass, and total biomass without and with age variables were established, respectively, to screen for the optimal model. Result The biomass of different parts of E. urophylla×E. grandis increased with age, but the proportion of each organ to the total biomass varied with age. The proportion of stem biomass increased with age, from 45.21% at 1 year old to 68.25% at 10 years old, whereas the proportion of branch and leaf biomass decreased with forest age, from 19.43% and 16.31% at 1 year old to 10.51% and 2.91% at 10 years old , respectively. The proportion of root biomass first increased from 19.05% at 1 year old to 25.21% at 3 years old, and then gradually decreased to 18.33% at 10 years old. The root to shoot ratio of E. urophylla×E. grandis ranged from 0.16 to 0.39. In selecting the optimal model for biomass of various organs, the model with DBH as the independent variable (without age variable) had better predictions for root biomass and total biomass than other models. The model with DBH 2 H plus age as independent variables had the best predictions for leaf biomass and aboveground biomass. The model with DBH, H, and age as independent variables had the best predictions for branch biomass. Regarding the prediction accuracy for stem biomass, there was no significant difference between the prediction models with DBHH and DBH 2 H plus age as independent variables, and both models could predict stem biomass well. Conclusion Forest age has significant impacts on the biomass allocation ratio of various organs in E. urophylla×E. grandis plantations. The prediction accuracy of branch, leaf, and aboveground biomass in E. urophylla×E. grandis plantations significantly improves if forest age is included in the allometric growth model. [Ch. 2 fig. 4 tab. 45 ref.]
, Available online doi: 10.11833/j.issn.2095-0756.20240160
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Objective This study, with an investigation of the classification of Osmanthus fragrans Colour Group and the changes of leaf color and related physiological characteristics during its growth, is aimed to provide theoretical basis for the classification, selection and improvement of Colour Group. Method With a total of 29 germplasm materials of Colour Group selected and classified by quantitative criteria and cluster analysis, two representative lines (‘Luocai 3’and‘Luocai 28’) were selected to observe the pigment distribution, component qualitative analysis, content determination and physiological index determination. Result Based on the cluster analysis at the stage of 30% leaf discoloration (S2), the cultivars were divided into two categories and three color series, namely the reddish brown series (the first subclass of Class Ⅰ), the orange brown series (the second subclass of Class I), and the purple pink series (the second subclass of Class Ⅱ). The anatomical structures of the two strains showed that anthocyanins were mainly distributed in the upper and lower epidermal cells of young leaves, and gradually decrease with leaf growth with the content of anthocyanins gradually decreasing, the content of chlorophyll continuing to rise and the content of carotenoids gradually increasing insignificantly. During the growth process of leaves, there was no significant pattern in the changes of soluble protein and soluble sugar content between the two, but they were relatively high in the S1 stage. The POD activity continued to increase, with‘Luocai 3’being higher than‘Luocai 28’ at each stage and the pH value of the leaves showed no significant change and remained within the acidic range. Conclusion Based on the leaf color parameters of the S2 period, a detailed color scheme division can be carried out for Colour Group. The color change of Colour Group leaves is mainly affected by the decrease in anthocyanin content and the increase in chlorophyll content, in which POD plays an important role. The difference between the reddish brown and orange brown series lies in the content and ratio of anthocyanins and carotenoids. [Ch, 7 fig. 1 tab. 29 ref.]
, Available online doi: 10.11833/j.issn.2095-0756.20240571
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Objective This study is in order to explore the effects of stand density on biomass and soil physicochemical properties in Pinus tabuliformis forests, for high-quality development and performance of the ecological service function. Method A 30-year-old P. tabuliformis forest in Caijiachuan watershed, Jixian County, Shanxi Province, was used as the research object, and the standard wood method was used to measure the biomass of individual plants and the overall biomass of the sample plots under the conditions of different densities, and the soil physicochemical properties were determined, so as to analyze the effects of stand density on the biomass of P. tabuliformis forest and soil physicochemical properties, and to determine their relationship by redundancy analysis (RDA) and Spearman’s correlation analysis. Result (1) The differences in stand biomass and total tree biomass between different densities were significant (P＜0.05), and with the increase of stand density, stand biomass gradually decreased, and the total tree biomass had a peak at a density of 1 750 plants·hm−2; (2) The physicochemical properties of soil in forests of different densities differed significantly (P＜0.05), with soil porosity being the highest at 1 750 plants·hm−2, reaching 52.38%, soil moisture content being the highest at 2 750 plants·hm−2, reaching 13.84%, and soil fertility being the best at a density of 1 750 plants·hm−2; (3) RDA and Spearman’s correlation analyses revealed that total soil porosity, organic carbon and quick-acting phosphorus were all highly significantly correlated with arbor biomass in the sample plots (P＜0.01), and below-ground biomass was significantly affected by soil water content (P＜0.05). Conclusion The stand density should be maintained at 1750 plants·hm−2 for the purpose of sequestering carbon and releasing oxygen and maintaining maximum productivity, and for the purpose of increasing the carbon sink capacity of the soil and improving fertility, and at 1 750−2 750 plants·hm−2 for the purpose of retaining soil and water and improving soil water retention properties. [Ch, 4 fig. 5 tab. 40 ref.]
, Available online doi: 10.11833/j.issn.2095-0756.20240253
Abstract:
Objective Frequent droughts caused by global temperature rise and precipitation pattern change have significant impacts on forest ecosystems, so information of plant water utilization and adaptation during and after droughts is crucial. Method The seedlings of Cunninghamia lanceolata were used as test material. A two-factor controlled experiment with 4 precipitation amount and 2 precipitation intervals gradients was set to investigate the response of non-structural carbohydrates (NSC) and related fractions content in different organs that suffer different precipitation amount and intervals. Result With the decrease of precipitation, NSC content of the seedlings showed an overall trend of firstly increasing and then decreasing in absorbing roots, transport roots, branches and leaves, and continuous decreasing in branches and trunks. C. lanceolata seedlings increased NSC content in transport roots, absorbing roots, leaves and branches, while hydrolyzed and converted the starch from the absorbing roots to soluble sugars to regulate intracellular water potentials; soluble sugars content showed an overall trend of continuous decreasing in transport roots and trunks, and an overall trend of firstly increasing and then decreasing in absorbing roots, leaves and branches; starch content of all organs showed an overall trend of firstly increasing and then decreasing. When precipitation was too low, C. lanceolata seedlings would consume NSC to preferentially meet the survival needs of absorbing roots, which led to a significant decrease of NSC content in transport roots, branches and twigs (P＜0.05). When precipitation intervals increased, NSC content in leaves and transport roots of the seedlings increased significantly (P＜0.05); soluble sugar content of leaves decreased significantly (P＜0.05), and soluble sugar content of transported roots increased significantly (P＜0.05). Conclusion To improve the survival of C. lanceolata plantation forests under changes in precipitation patterns, soil water content should be maintained at more than 50% of the average monthly precipitation in the local multi-year dry season, and watering intervals can be extended in areas with higher precipitation. [Ch. 3 fig. 1 tab. 51 ref.]
, Available online doi: 10.11833/j.issn.2095-0756.20230604
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Objective The objective of this study is to investigate bird communities in parks, roadside green spaces, and community green spaces in Kunming urban construction zone, analyze the differences in bird community composition across different recreational green spaces and their root causes, and explore the impact of urban green space environments on bird communities. Method From July 2021 to August 2022, birds were investigated in three types of recreational green spaces in Kunming City. Redundancy analysis and multiple linear regression were used to analyze the relationship between the diversity of resident birds and environmental factors during breeding and non-breeding seasons. Result (1) A total of 31 058 individuals in 176 species were recorded, belonging to 17 orders and 53 families, which included 1 species under national first-class key protection and 12 species under national second-class key protection. (2) Parks had the highest richness, abundance, and Shannon-Wiener diversity index of bird species, followed by roadside green spaces, and community green spaces had the lowest. However, the Pielou evenness index showed the opposite trend. (3) Redundancy analysis indicated that other internal environmental factors, except for the green space shape index, had a promoting effect on improving bird diversity. (4) Multiple linear regression showed the building index in buffer zones of 50 and 400 m was negatively correlated with bird diversity. The distance from the city center was positively correlated with bird diversity. The distance from Dian Lake was negatively correlated with bird diversity in roadside green spaces. The distance from the mountain was positively correlated with bird diversity in roadside green spaces, but negatively correlated with bird diversity in community green spaces. Conclusion In the future construction of recreational green spaces, it is necessary to reduce the impact of surrounding buildings on parks and roadside green spaces, increase heterogeneous landscape habitats, and focus on enhancing the richness of vegetation communities inside community green spaces. [Ch, 3 fig. 3 tab. 28 ref.]
, Available online doi: 10.11833/j.issn.2095-0756.20240574
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Objective The radial growth dynamics of xylem is considered one of the indicators of sensitivity to environmental change. Investigating the xylem formation is crucial to elucidate the relationship between trees growth and the climate. Method Microcore sampling and paraffin sections technology were used to monitor the intra-annual growth dynamics of xylem formation. We collected the microcores of Catalpa bungei, Cinnamomum camphora, Fraxinus chinensis and Koelreuteria paniculata every 7−10 d, and Gompertz model was used to fit the modeled value of cumulative radial growth. Result (1) Cambial activity began in early March and ended in mid-October. The duration of cambial activity was shortest for C. bungei [(189±14.6) d], and longest for C. camphora [(216±17.4) d]. (2) Four species finished the xylem differentiation in early November, and their maximum growth rate occurred in the middle of May. However, the widths of cumulative radial growth showed great variations among four ring-porous species which were from (5 807±2 192.9) μm for F. chinensis to (8 276±1 744.2) μm for C. bungei. (3) Additionally, temperature may be the main climatic factor influence the radial growth in study area. Both air temperature and surface ground temperature had a significantly positive correlation on the xylem growth increment for four ring-porous wood species (P＜0.01). The positive correlation between precipitation and xylem growth was only in C. camphora (r=0.39, P＜0.05). It may explained by the smallest diameter and area of vessel of C. camphora, which led to the trees were more sensitive to precipitation. Conclusion The radial growth of the four tree species in the local area is highly significantly positively correlated with air temperature. The response of the C. camphora plants to climatic factors is stronger than the other three ring-porous porous tree species. [Ch, 5 fig. 4 tab. 52 ref.]
, Available online doi: 10.11833/j.issn.2095-0756.20230532
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Objective This study, with an investigation into the temporal and spatial changes of soil microbial diversity in the habitat of the rare plant Emmenopterys henryi and the main controlling factors of these changes, is aimed to provide reference for the protection and breeding of the rare species. Method High throughput sequencing technology was used to detect OTUs of bacteria and fungi in soil from 34 E. henryi dominated stands before an analysis was conducted of the effects of altitude, slope direction, soil nutrition, and characteristics of the tree communities on the diversities of soil bacteria and fungi. Result α diversity analysis indicated that: the mean of Shannon-Wiener index of bacterial communities was 5.87, and that of fungal communities was 0.98; the numbers equivalent of Shannon-Wiener index (H') decreased significantly with the increase of altitude (P＜0.05) and increased significantly with the increased soil pH (4.62 − 5.83) (P＜0.05); meanwhile, the numbers equivalent of Simpson index (D') was significantly and negatively correlated with the content of available potassium in soil (P＜0.05); H' and D' of soil fungi firstly decreased and then increased with the increased altitude, and significantly decreased with the increased alkali-hydrolyzed nitrogen content in soil (P＜0.05); meanwhile, there was a significant and positive correlation between D' and the basal area of the central E. henryi tree (P＜0.05). β diversity analysis indicated that: the mean Sorenson index of bacterial communities was 0.39, with 70.2% contributions of species turnover component, and that of fungal communities was 0.72, with 85.1% contributions of species turnover component; the Sorenson indices of soil bacterial and fungal communities were both significantly spatial auto-correlated (P＜0.05), and correlated with differences in soil nutrient content and tree species composition. The partial Mantel test results indicated that: the species turnover components of bacteria were significantly correlated with differences in soil nutrient content and tree species composition (P＜0.05), while the species richness difference of soil bacteria was significantly correlated with the difference in sampling year (P＜0.05); the species turnover components of fungi were significantly spatially auto correlated (P＜0.05), and correlated with differences in soil nutrient content, while the species richness difference of fungi was significantly correlated with the differences in sampling year and the altitude (P＜0.05). Conclusion Compared with other forests in China, the habitat of E. henryi in Jiulongshan boasts more diverse soil fungal, less diverse soil bacterial and higher spatiotemporal heterogeneity in soil microbial diversity. Altitude, soil alkaline nitrogen content, and the size of E. henryi tree are the main factors affecting α diversity of soil microbes, while soil physicochemical properties and the composition of tree communities are the main factors that influence β diversity of soil microbes. [Ch, 4 fig. 2 tab. 32 ref.]
, Available online doi: 10.11833/j.issn.2095-0756.20230505
Abstract:
Objective The acceleration of urbanization leads to the change of urban underlying surface, serious landscape fragmentation, and continuous intensification of urban heat island effect, especially in the urban center where buildings and populations are highly clustered. The establishment of reasonable ecological network has become one of the important ways to improve the urban ecological environment. Method Based on the “source-sink” theory, this study used morphological spatial pattern analysis (MSPA) and landscape connectivity index to select the “source” and “sink” landscapes with good landscape stability and high connectivity as ecological sources in the study area. The minimum cumulative resistance model, gravity model and hydrological analysis module were used to construct and screen important ecological corridors in the study area, so as to establish a multi-level “source-sink” landscape network to alleviate urban thermal environment problems. Result The results showed that 24 core patches with important connectivity were selected as important ecological sources. There were 102 “source-source” corridors, 141 “source-sink” corridors, 325 “source-sink” corridors, 103 ecological nodes and 148 obstacle points. Through comprehensive superposition, the first-level compensation corridor was mainly composed of Minjiang River, Pihe River and other river channels, the second-level transport corridor was mainly distributed in the area with dense “sink” landscape, and the third-level action corridor was mainly distributed in the high-intensity construction area. Conclusion The optimization pattern of a multi-level ecological network based on the “source-sink” theory is an important measure for effectively mitigating the urban heat island effect. [Ch, 4 fig. 3 tab. 25 ref.]
Diversity characteristics of herbaceous species under Robinia pseudoacacia forest in different years
, Available online doi: 10.11833/j.issn.2095-0756.20240128
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Objective This study, with an investigation into the species composition and diversity index of herbaceous layer under Robinia pseudoacacia forests in the hilly gully region of the Loess Plateau, is aimed to explore the characteristics and main influencing factors of its diversity index, in order to provide reference for the practice of regional vegetation restoration. Method With the R. pseudoacacia forests of different years (7, 12, 22 and 45 years) in Zichang City selected as study subjects, the species composition of the herbaceous layer in the understorey of R. pseudoacacia forests of different years were investigated employing the “space instead of time” method and the plot survey method before an analysis was conducted of the main factors influencing the diversity index using redundancy analysis (RDA). Result (1) There were 55 species of herbaceous species in R. pseudoacacia forests of different years, belonging to 18 families, and their dominant species were mainly Asteraceae, Gramineae and Leguminosae, with the overall performance showing that the dominant species belong to a few families, while the subordinate species belong to most families; the Artemisia vulgaris, A. caruifolia and A. gmehinii have higher importance values; (2) The aboveground biomass of understory herbaceous in R. pseudoacacia forests increased with years, and planting years increased significantly the aboveground productivity of the herbaceous layer (P＜0.05). (3) Ammonium nitrogen, soil organic carbon, soil moisture and total phosphorus were the main factors influencing the Margalef and Simpson index of species diversity as well as aboveground biomass of the understory herbaceous layer whereas total nitrogen, total phosphorus, ammonium nitrogen, and soil silt were the main factors affecting Shannon-Wiener and Pielou index. Conclusion The herbaceous layer of R. pseudoacacia forests in the study area showed different species diversity at different years. Artemisia plants showed great adaptive ability at different years, and species diversity indicators and biomass are significantly affected by soil moisture and nutrients. Therefore, it is important to focus on the balance of soil moisture and nutrients in future afforestation practices in the Loess Plateau region to enhance the stability and sustainability of plantation ecosystem development. [Ch, 2 fig. 2 tab. 31 ref.]
, Available online doi: 10.11833/j.issn.2095-0756.20240109
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Objective In order to study the effects of different kinds and amount of biochar on the growth and nutrition of Acer truncatum seedlings, the better biochar and its application amount are selected to provide a theoretical reference for the scientific application of biochar in A. truncatum seedlings. Method The seedlings were used as experimental objects, and pot experiments were carried out. Conventional light substrate without biochar was taken as the control (ck1). 3 types of biochar (rubber biochar, rice husk biochar and bamboo biochar) with addition of 30.0, 50.0 and 70.0 g·kg−1 were set up. The growth, biomass, photosynthetic index, root morphology and nutrition of the seedlings under different treatments were determined. The principal component analysis and membership function analysis of the seedlings were used to comprehensively evaluate the indicators and explore the best biochar and addition proportion. Result The growth, biomass, root morphological index, photosynthetic index and nutrient content of the seedlings were all promoted by adding biochar to the substrate, the effect of rice husk biochar on seedling height, stem diameter, photosynthetic index and root morphology was better than that of bamboo biochar and rubber biochar. 50.0 g·kg−1 rice husk biochar addition proportion was the best for root growth of seedlings, compared with ck1, the total root length, total root surface area, total root volume and average root diameter increased by 98.79%, 110.22%, 175.00% and 37.50%, respectively. 70.0 g·kg−1 rice husk biochar addition proportion had significant effects on chlorophyll, net photosynthetic rate, stomatal conductance, and transpiration rate, compared with ck1, which increased by 50.00%, 221.76%, 200.00% and 146.91%, respectively. The evaluation index of seedlings with 50.0 g·kg−1 rice husk biochar was the highest (0.665), which was the best amount of biochar. Conclusion The addition of biochar to the the substrate could promote the absorption and utilization of nutrients in A. truncatum seedlings. It is suggested that 50.0 g·kg−1 rice husk biochar should be preferentially selected when adding biochar to A. truncatum seedling substrate. [Ch, 3 fig. 4 tab. 31 ref.]
, Available online doi: 10.11833/j.issn.2095-0756.20240107
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Objective This study aims to explore the advantages of acquiring three-dimensional point cloud of forests based on backpack laser scanning (BLS) and unmanned aerial vehicle laser scanning (ULS) technology, and use LiDAR360 MLS and LiDAR360 software to realize accurate measurement of single tree diameter at breast height (DBH) and tree height, meanwhile, determine the optimal method for individual tree segmentation and extraction. Method Taking 6 circular plots of Pinus yunnanensis natural pure forest with a radius of 15.0 m in Luomian Township, Fumin County, Yunnan Province as an example, the iterative closest point algorithm (ICP) was employed to fuse BLS and ULS point cloud. LiDAR360 MLS and LiDAR360 software were used to denoise, classify, normalize, segment individual trees and extracted DBH and tree height of individual trees from the point cloud data. The correlation between measured values and estimated parameters was established by linear fitting, and the estimation effect of DBH and tree height was evaluated. Result Compared with LiDAR360 based on elevation information for classification, LiDAR360 MLS based on deep learning for classification was more in line with reality in the number of tree extraction. The tree extraction results from BLS and fusion point cloud were consistent, and the recall rate reached 100%. ULS performed single tree segmentation through seed points, with accuracy, recall, and F-measure of 94.59%, 88.98%, and 91.70%, respectively. However, due to canopy connectivity, there existed some under-segmentation and over-segmentation. The determination coefficient (R2) and root mean square error (ERMSE) of DBH extraction based on BLS were 0.904 and 2.046 cm, respectively. R2 and ERMSE extracted by tree height were 0.791 and 1.173 m, respectively. The fusion point cloud was affected by discrete points around the trunk, and the DBH extraction effect was relatively poorer than BLS. R2 and ERMSE were 0.881 and 2.284 cm, respectively. However, the information of canopy and understory of fusion point cloud was more complete, and the estimation accuracy of tree height was higher than that of BLS, with R2 and ERMSE values of 0.933 and 0.812 m, respectively. Conclusion Due to differences in working principles, ULS and BLS technologies each have their own advantages in acquiring point cloud from the canopy and understory. The combination of ULS and BLS can achieve a complementary effect, which can reflect the forest spatial structure more precisely, and realize the high-precision extraction of DBH and tree height. [Ch, 5 fig. 3 tab. 28 ref.]
, Available online doi: 10.11833/j.issn.2095-0756.20240157
Abstract:
Objective The dredging sediment from rivers, lakes, reservoirs and ponds can be used for the production of high-economic value landscape plants such as turf, which can not only solve the problem of occupying cultivated farmland and destroying top soil layer, but also solve the treatment and disposal problem of organic solid waste such as sediment. Method Based on the mixed material design and the principle of maximum consumption of river sediment, the proportion of the three raw materials, namely sediment, biogas residue, and biochar, was set to be 50%≤sediment≤100%, 0≤biogas residue≤50%, and 0≤biochar≤10%, respectively, totaling 13 treatments. Meanwhile, cultivated soil was set as the control, and the growth indicators (biomass dry mass, chlorophyll, root activity) and physiological indicators (soluble sugar, malondialdehyde, antioxidant protective enzymes) were measured to explore the feasibility and suitability of planting Agrostis stolonifera ‘PENN A-4’ with the substrate of river sediment as the main material instead of the traditional cultivated soil. Result Compared with the control, the dry weight of above ground part and underground part of A. stolonifera ‘PENN A-4’ significantly increased by 58.53% and 17.19%, respectively (P＜0.05) and the root activity nearly doubled (P＜0.01) when the proportion of sediment in the mixed substrate was 75.00%, the proportion of biogas residue was 20.00%, and the proportion of biochar was 5.00%, but the content of chlorophyll a and b in plants decreased by approximately 20.00% (P＜0.01). In addition, the mixed substrate significantly increased superoxide dismutase activity (28.66%, P＜0.01), but had no significant effect on the contents of soluble sugar and malondialdehyde, catalase activity and peroxidase activity in plants. Conclusion It is feasible to use river sediment as the main material, mixed with an appropriate proportion of biogas residue and biochar as a substrate instead of cultivated soil for A. stolonifera ‘PENN A-4’ planting. The mixed biogas residue can effectively increase the aboveground biomass and root vitality of the turf grass, while biochar can effectively increase the underground biomass of the grass. [Ch, 5 fig. 4 tab. 25 ref.]
, Available online doi: 10.11833/j.issn.2095-0756.20240166
Abstract:
Stress is one of the major reasons causing global crop yield decline. Under stress conditions, the intracellular protein trafficking needs to be adjusted rapidly to ensure the correct delivery of the associated cargo molecules via endomembrane system. The endomembrane system in eukaryotic cells contains diverse membrane-bound organelles, which are accurately and efficiently generated in a well-organized way. These organelles play essential roles in protein transport. The endosomal sorting complex required for transport (ESCRT) complex mediates the biogenesis of prevacuolar compartment/multivesicular body (PVC/MVB), facilitating the vacuolar trafficking of the ubiquitinated proteins. This review highlights the recent research on ESCRT machinery in plant stress responses, including the basic composition and function of ESCRT, and the regulatory role of ESCRT in plant abiotic stress (i.e. drought and salt stress) and innate immunity. To explore how ESCRT specifically recognizes and regulates stress response proteins, it will be helpful to construct a more precise ESCRT-mediated molecular regulatory network of stress responses. [Ch, 2 fig. 1 tab. 70 ref.]
Stress is one of the major reasons causing global crop yield decline. Under stress conditions, the intracellular protein trafficking needs to be adjusted rapidly to ensure the correct delivery of the associated cargo molecules via endomembrane system. The endomembrane system in eukaryotic cells contains diverse membrane-bound organelles, which are accurately and efficiently generated in a well-organized way. These organelles play essential roles in protein transport. The endosomal sorting complex required for transport (ESCRT) complex mediates the biogenesis of prevacuolar compartment/multivesicular body (PVC/MVB), facilitating the vacuolar trafficking of the ubiquitinated proteins. This review highlights the recent research on ESCRT machinery in plant stress responses, including the basic composition and function of ESCRT, and the regulatory role of ESCRT in plant abiotic stress (i.e. drought and salt stress) and innate immunity. To explore how ESCRT specifically recognizes and regulates stress response proteins, it will be helpful to construct a more precise ESCRT-mediated molecular regulatory network of stress responses. [Ch, 2 fig. 1 tab. 70 ref.]
