[Objective] A new storey identification method-Maximum Light Receiving Plane (MLRP) method was developed to identify forest story of typical natural broad-leaved forests in mid-subtropical zone in accordance with whether the tree crowns could receive sunlight directly and the extent of direct sunlight the crowns received, which provide a new way in revealing the patterns of vertical structure of the natural broad-leaved forests in mid-subtropical zone.[Method] The typical natural broad-leaved forests in mid-subtropical zone could be identified as Light Receiving Storey (LRS) and Non-Light Receiving Storey (NLRS) by the MLRP method. The LRS could be separated further by ward method of cluster analysis according to tree height.[Result] The five sample plots of typical natural broad-leaved forests in mid-subtropical zone were divided into LRS(Ⅰ) and NLRS(Ⅱ) by the MLRP method, LRS comprised substorey Ⅰ₁ and Ⅰ₂. The results of MLRP method of the five sample plots indicated that the height of interface between LRS and NLRS (i.e. the height of the interface between storey Ⅰ and Ⅱ) were 17.0, 16.5, 17.0, 17.0,and 16.0 m, and the height of interface between substorey Ⅰ₁ and Ⅰ₂ were 25.0, 27.0, 25.0, 22.9,and 25.0 m, respectively. The volume of per hectare of various substoreys, height difference between adjacent storeys and the mean diameter at breast height of various substoreys all conformed to National Standards (GBT 26424-2010) when the storeys were identified by the MLRP method.[Conclusion] The MLRP was proven by CVPA-H curves, it is a simple and practicable field operation without measuring heights of all trees but just by judging whether the tree crowns received direct sunlight and whether the tree crowns were evidently outstanding in the stand (i.e. the extent of direct sunlight received). Comparisons of the storey identification by MLRP method with profile diagram, the changes of variation coefficients of height of different storey identified, and whether the calculations of stand description factors at substoreys conforming to storey identification of the National Standards (GBT 26424-2010) further proved that the MLRP method was scientifically sound. The MLRP method could better reflect the patterns of natural differentiation of vertical structure of the natural broad-leaved forests in mid-subtropical zone. It also reflected the consequence of competition among trees for light and spatial resource, implying a biological significance.

[Objective] To reveal mechanisms of soil fertility enhacement in moso bamboo (Phyllostachys edulis) stands and to provide data for the estimation and simulation of carbon (C) balance in forest ecosystems, we investigated the effects of fertilization on spatial and temporal pattern of soil organic carbon (SOC) in the west of Fujian province.[Method] 18 sample plots, in a size of 20 m×20 m, were set in typical pure moso bamboo forest with good growth, using randomized block design in Tianbaoyan National Nature Reserve in Yong'an. Six treatments were applied, including 5-year applications of specialized fertilizer for bamboo (Ⅰ), formula fertilizer fused with nitrogen (N)-phosphorus (P)-potassium (K) (Ⅱ),organic fertilizer (Ⅲ), 1-year applications of specialized fertilizer for bamboo (Ⅳ), organic fertilizer (Ⅴ),and non-fertilization (Ⅵ). SOC contents under different fertilization treatments, soil depths and seasons were analyzed to reveal the vertical distribution and seasonal dynamics of SOC and its relationship with soil quality in moso bamboo forest.[Result] Fertilization had no significant effects on the average SOC content in 0-100 cm soil layer. However, fertilization treatments (Ⅰ-Ⅴ) significantly decreased the SOC content in 0-10 cm soil layer by 9.05%, 27.33%, 28.84%, 18.92%, 25.37% and in 10-20 cm layer by 1.25%, 23.68%, 23.47%, 20.48%, 18.61%, respectively, whereas SOC contents in 80-100 cm layer increased by 2.72%-37.14%, suggesting that fertilization exhibited positive effects on SOC content with soil depth. In addition, SOC content and its standard error decreased with soil depth, indicating that soil C in deep layer was more stable than that in top layer. No significant seasonal changes of SOC content in bamboo forests was observed, but the SOC concentrations in autumn and winter is slightly higher than that in spring and summer. Moreover, SOC content was significantly positively correlated with soil total N, total P, hydrolysis N, available P and available K,but significantly negatively correlated with soil bulk density and pH.[Conclusion] Short-term fertilization had no significant effects on the average SOC content in the 0-100 cm soil layers and the vertical distribution pattern of SOC, but led to a significant decline of SOC in the top soil layers and a slightly increase of SOC in deep soil layer. Moreover, fertilization had no significant effects on the seasonal dynamics of SOC content, indicating that sample data was not a main determinant. Furthermore, SOC content was significantly correlated with soil total N, total P, hydrolysis N and other soil quality factors, demonstrating that minimized soil disturbance, timely and appropriate nutrient supplements, appropriate collection of bamboo shoots and cuttings of bamboo would help to maintain a high level of SOC content and long-term productivity.

[Objective] Seven natural stand types were investigated to understand the soil microbial community. The main forest species were Picea crassifolia, Betula platyphylla, Larix gmelinii, Populus davidiana. The purpose of this study was to improve management and evaluation strategies of the forest by adjusting the structure and restoring the degraded forest.[Method] The 7 stand types were Datong Picea crassifolia (A), Datong Betula platyphylla (B), Huangzhong Picea crassifolia+Betula platyphylla (C), Ledu Larix gmelinii+Betula platyphylla (D), Minhe Populus davidiana (E), Xunhua Populus davidiana+Betula platyphylla (F),and Jianzha Picea crassifolia (G) in Qinghai Province. The soil physical-chemical properties and soil microbial community composition were investigated by conventional laboratory analysis and phospholipid fatty acids (PLFAs) analysis. Changes of individual PLFA signatures and correlations between soil properties and soil microbial group of PLFA indicators were analyzed by principal components analysis (PCA) and redundancy analysis (RDA), respectively.[Result] A total of 17 different PLFAs with different types of biomarkers were detected in the soil samples among different stand types. The stand types A and B exhibited a larger number PLFAs compared with other stand types. The lowest number of PLFAs was found in stand type G. The PLFAs biomarker was variable in different stand soils. The highest content was 16:0. The highest richness of PLFAs was saturated fatty acid. The highest total content of PLFAs biomarkers was found in stand B, and the lowest in stand G. The contents of bacteria and fungus PLFAs displayed the following order:broad-leaved stand > mixed broadleaf-conifer stand > conifer stand. The Simpson index, Shannon-Wiener index of stands F and G were significantly lower than those of the other stand types. McIntosh index were holistically higher in stand types A, B and D than in the other types. Principal Component Analysis (PCA) showed that generalized bacteria and Gram positive bacteria were the main soil microbial group. Redundancy analysis (RDA) indicated that the effects of pH, soil moisture and fine root biomass on soil microbial community were higher than those of soil organic carbon, bulk density and litter standing crop.[Conclusion] Soil microbial community composition and impact factors were significantly different among different stand types. Therefore, the management and utilization of forest ecosystem should consider the change of soil microbial community characteristics, in order to improve forest management practices.

[objective] Growth-regulating factors (GRFs) are plant-specific transcription factors that are involved in various developmental events, especially in root development. It is interesting to investigate the roles of GRFs in growth and development of tissues and organs, rooting in particular, in woody plants, which would not only increase our knowledge on the mechanisms of the regulation of adventitious root formation and also be useful for cutting propagation in woody plants.[Method] PtGRF1/2d gene and its promotor were isolated from Populus alba×P. glandulosa ‘84K’. The overexpression vector of miR396-resistant construct 35S:mPtGRF1/2d-GFP and the promoter-testing vector of P_PtGRF1/2d∷GUS was generated. The miR396-resistant version of mPtGRF1/2d contained six silent mutations within the miR396-complementary domain of the PtGRF1/2d genomic clone, thereby increasing the number of mismatches between miR396 and mPtGRF1/2d without altering the amino acid sequence of the encoded PtGRF1/2d protein. mPtGRF1/2d overexpression transgenic poplars and P_PtGRF1/2d∷GUS transgenic poplars were obtained respectively. Expression characters in P_PtGRF1/2d∷GUS transgenic poplars and time of adventitious root appearance, the number and length of adventitious roots in overexpression transgenic poplars were analyzed. The expression of related transcript factors at early stage of adventitious root formation in overexpression transgenic poplars were analyzed by qRT-PCR.[Result] The results showed that the expression of PtGRF1/2d was mainly in the pericycle and tip of root, suggesting general involvement of PtGRF1/2d in the root development. The development of adventitious roots in mPtGRF1/2d overexpression transgenic poplars was significantly affected in comparison to the non-transgenic poplars used as controls. Overexpression of PtGRF1/2d caused not only the delayed initiation of adventitious roots but also the reduced number and length of adventitious roots, which indicates that PtGRF1/2d exhibits a negative regulation on initiation and development of adventitious root. qRT-PCR analysis indicated that the expression of 5 transcript factors previously shown involvement in adventitious root formation, including PtSCR, PtAIL9, PtBBM2, PtPLT1.2 and PtWOX11b, was down-regulated at early stage of adventitious root formation in overexpression transgenic poplars, which demonstrated that overexpression of PtGRF1/2d suppressed the expression of key factors for adventitious root formation thus resulted in the delayed formation of adventitious roots and the reduced number and length of adventitious roots, and finally influenced the growth of poplar.[Conclusion] PtGRF1/2d is a negative regulator of poplar adventitious root formation, functioning in the upstream of adventitious root formation regulation pathway, down-regulates the expression of adventitious root related factors for adventitious root formation thus suppresses the induction of the root primordium and adventitious root formation, and finally leads to the delayed adventitious roots appearance and the reduced number and length.

[Objective] Phloem unloading and postphloem transport play pivotal parts in the regulation of the distribution of sucrose in the storage organs and maintenance the sink of fruit, and largely determine the yield and quality of the crop. The objective of this study was to clarify the mechanism of phloem unloading and glucose metabolism in the phloem of blueberry.[Method] Vaccinium corymbosum ‘Sierra’(5-year-old Highbush blueberry) was used for observation of the ultrastructure of the phloem of blueberry in each development period. Fluorescent dye tracer and laser scanning confocal microscopy were used to observe the unloading path of the phloem in the fruit timely. Determination of soluble sugar content and related metabolic enzyme activity in blueberry fruit by HPLC.[Result] An ultrastructural investigation of phloem tissue in blueberry fruit showed that the fruit phloem SE/CC complex is symplasmically isolated from surrounding parenchyma cells over fruit development, whereas a large number of piasmodesma exist between parenchyma cells and pulp cells. Confocal laser scanning images of carboxyfluorescein unloading showed that the dye remained confined to the phloem strands,not spread to the surrounding parenchyma cells, during the whole fruit development.These results provided a clear evidence for the predominance method of the assimilation of blueberry fruit is the unloading pathway over blueberry fruit development and symplasmic pathway present in postphloem transport. A large number of cells are beneficial to the material exchange between parenchyma cells,parenchyma cells and flesh cells. Activity assay showed that,invertase activity remained at a high level, it provides evidence to confirm the apoplasmic phloem unloading pathway at blueberry fruit development. In addition,carbohydrate metabolism related enzyme activity assay shows that a great amount of glucose and fructose primarily accumulated during blueberry ripening and sucrose enzyme decomposition activity was always greater than synthetic activity. During the late stage of fruit development, the activity of soluble acid invertase and neutral invertase was increased, the activity of sucrose decomposition, transformation and storage in the fruit pulp cell was revealed,the accumulation process is positively correlated with the activities of invertase, sucrose synthase and sucrose phosphate synthase enzymes. In the process of fruit development, the comprehensive effect of sucrose metabolism related enzymes is an important factor affecting the accumulation of soluble sugar in blueberry fruit.[Conclusion] These results provided clear evidence for the predominance method of the assimilation of blueberry fruit is the unloading pathway over blueberry fruit development and symplasmic pathway present in postphloem transport. A large amount of glucose and fructose primarily accumulated in blueberry and sugar accumulation was positively correlated with invertase, sucrose synthase and sucrose phosphate synthase.

[Objective] Drought has become a key factor affecting plant growth in the world. Hence, it is necessary to study the xylem embolism and refilling. The aim of this study was to explore the relationship between hydraulic traits and embolism refilling in the xylem of six tree species, to elucidate the influence of xylem hydraulic traits on the embolism refilling, and to provide theoretical evidence for screening drought-resistant tree species.[Method] Six well-growing tree species, Robinia pseudoacacia, Hippophae rhamnoides, Ulmus pumila, Acer truncatum, Salix matsudana and Corylus heterophylla were studied. Cochard Cavitron centrifuge was used to induce xylem embolism of one-year-old twigs when percentage loss of conductivity was higher than 95%. The "vulnerability curves" of six tree species were plotted to obtain the mean value of P₅₀. The recovery level of different periods (20, 40, 60, 80, 100 min) was measured by Low Pressure Flow Meter with multi-channels and staining methods. At the same time, the hydraulic diameter, pre-dawn water potential of xylem and natural percentage loss of conductivity (NPLC) were measured.[Result] 1) The order of the average P₅₀ values of the six species was R. pseudoacacia > U. pumila > H. rhamnoides > S. matsudana > C. heterophylla > A. truncatum, and A. truncatum was the most drought-tolerant tree species; 2) The recovery level of the xylem embolism by staining method was consistent with embolism recovery level by Low Pressure Flow Meter. The regression equation was y=1.047x-7.567, R²=0.863. The LPFM method can completely reflect the recovery level of the embolism branches in different time periods; 3) The xylem embolism recovery capacity of the six tree species was ranked as follows:R. pseudoacacia > U. pumila > H. rhamnoides > S. matsudana > C. heterophylla > A. truncatum. This implies that tree species with the high recovery ability of xylem embolism can quickly restore the function of transporting water when the plants are resupplied with water. The results showed that the order of the abilities of xylem embolism refilling was completely consistent with the order of embolism vulnerabilities. The ability of embolism refilling increased with embolism vulnerability (R²=0.980). Regression analysis indicated that the ability of embolism refilling of the six tree species was strongly correlated with hydraulic diameter, pre-dawn water potential of xylem, NPLC, with values of R² of 0.868, 0.740, 0.741, respectively.[Conclusion] The hydraulic traits of xylem were closely related to the refilling ability of xylem embolism. In particular, there was a strong positive correlation among P₅₀, hydraulic diameter and the ability to recover from embolism. Therefore, P₅₀ and hydraulic diameter were the main influencing factors for embolism refilling.

[Objective] We compared the effects of different dehydration conditions on germination of dormancy-released seeds of Fraxinus mandshurica and explored the intrinsic physiological changes of seeds under different conditions to provide theoretical and technical basis for redrying and storage of dormancy-released seeds of F. mandshurica.[Method] Using single factor design, the dormancy released seeds of F. mandshurica were used to investigate seed germination ability after dehydration at different temperatures(5, 10, 15, 20, 25, 30, 35℃). Then, the effects of dehydration temperature(normal temperature 20℃ and low temperature 5℃), dehydration speed(slow and fast), and their interaction on seed germination after dehydration were investigated using two factor design. In order to determine the response of seed cell membrane permeability, antioxidant system enzyme activity and storage material metabolism to different dehydration treatments, the activities of antioxidant enzymes (SOD, POD and CAT), malondialdehyde (MDA) content, soluble sugar, soluble protein and starch contents in seeds under different conditions were measured.[Result] The seed germination rate and germination index showed the trend of increasing at the beginning and then decreasing with the rising of the dehydration temperature, and the germination time of seeds showed the opposite trend. The germination ability of seeds dehydrated at normal temperature (20℃) was the best, and the germination ability of seeds dehydrated at high temperature(35℃) or low temperature(5℃) was weak. Compared with the normal temperature dehydration, the relative electrical conductivity and MDA content of seeds dehydrated at low temperature increased significantly, the POD and CAT enzyme activity in embryos was significantly decreased, no significant changes in the contents of soluble sugar and starch in the seeds, but soluble protein content decreased significantly. Compared with the slow speed dehydration, the relative electrical conductivity and MDA content of seeds dehydrated at fast speed increased significantly, the SOD and POD enzyme activity in embryos was significantly decreased, no significant changes in the contents of soluble sugar and starch in seed, but soluble protein content decreased significantly.[Conclusion] The optimum dehydration temperature for dormancy-released seeds of F. mandshurica is 20℃, high (35℃) or low (5℃) temperature dehydration can lead to the declined seed germination rate and germination index, and the prolonged germination time. After dehydration at low temperature or fast dehydration, the relative electrical conductivity and MDA content of the seeds were increased significantly, the activity of antioxidant enzymes in seed embryos and the soluble protein content of the seeds decreased significantly. These changes should be the causes for the decrease of seed germination ability. The activity of antioxidant enzymes in seed embryos had different responses to dehydration with low temperature and fast dehydration. POD and CAT were more sensitive to dehydration at low temperature, but SOD was more sensitive to fast dehydration. SOD, POD and CAT must be coordinated, so that the active oxygen free radicals can be maintained at a low level and harmless to the cells. The decline of the protective function during dehydration at low temperature or fast dehydration is mainly related to the changes of protein, but not the changes of soluble sugar or starch.

[Objective] In order to reveal feasibility of different concentrations of BRs, BT and SA on Citrus aurantium under low temperature stress, the effects of BRs, BT and SA on physiological index were studied.[Method] Pot C. aurantium seedlings cultured under the same outdoor conditions were sprayed on the leaves with BRs, BT and SA separately, and then placed in the low incubator [0℃/4℃,(day/night),light intensity of 600 μmol·m^-2s^-1], and the seedlings sprayed with distilled water and set at 25℃ were served as control Ⅰ(CK₁), and the seedlings sprayed with distilled water and set at low temperature stress (0℃/4℃, day/night) were served as control Ⅱ(CK₂). The relative electric conductivity, contents of proline, malondialdehyde, soluble protein, chlorophyll, and activities of SOD, POD and CAT were measured.[Result] Compared with normal temperature CK₁, low temperature significantly inhibit the antioxidant enzyme activity of CK₂, enhanced the cell membrane damage and brought about loss of the normal functions of cell membrane. Thus, low temperature stress caused some increase in relative electric conductivity and MDA content of C. aurantium seedlings. Low temperature stress treatment also destroyed the structure of the chloroplast, causing the decomposition of photosynthetic pigment and reducing the content of chlorophyll and carotenoid. Compared with CK₂, 0.15 mg·L^-1 BRs, 10 mmol·L^-1 BT, 1 mmol·L^-1 SA enhanced the activities of POD, SOD, and CAT, increased the contents of proline and soluble protein, and effectively reduced the damage of low temperature stress on cell membrane. At the same time, the exogenous BRs, BT and SA increased the contents of chlorophyll and carotenoid, the efficiency of leaf photosynthesis and thus effectively resisted the oxidative stress caused by low temperatures. But with the increasing concentration of spraying, the ability of C. aurantium to resist low temperature stress decreased.[Conclusion] The foliage spraying with BRs, BT and SA could reduce the damage of low temperature stress on C. aurantium seedling leaves.

[Objective] The growth of one-and two-year-old Castanopsis hystrix seedlings raised with different media and different sizes of containers were compared, and their out-planted performances were also evaluated, aiming to determine the optimum container size and medium, as well as to provide guidance to selection of suitable seedling age for planting.[Method] C. hystrix seedlings were raised in containers of two sizes with eleven media. Growth dynamics and early field performance were investigated, respectively. Variance analysis with Duncan's multiple comparison was conducted to test differences in seedling growth and the early field performance among treatments, and correlation analysis was used to determine the relationship between seedling growth and early filed performance.[Result] Container size and growing medium significantly influenced height, root collar diameter, root and total biomass of one-and two-year-old seedlings. Moreover, their interaction significantly affected height, root collar diameter and root biomass of one-and two-year-old seedlings as well as total biomass of two-year-old seedlings. For one-year-old seedlings, there was significant difference in height but not in survival rate among media in the first year after out-planting. A significant difference was found in root collar diameter but not in height and survival rate in the second year after out-planting. For two-year-old seedlings, there were profound effects of container size and medium on height and root collar diameter in the first year after out-planting. Moreover, the interaction of container size and medium influenced obviously the height of two-year-old seedlings in the first year after planting. The height in the first year, and height and root collar diameter in the second year after planting showed positive relationships with the height, root collar diameter and total biomass of one-year-old seedlings in the nursery, respectively. However, the height in the first and second year after planting were negatively correlated with the root and shoot ratio in the nursery, respectively. As for two-year-old seedlings, with container size one, their height and root collar diameter at the first year after planting were positively correlated with the height and total biomass in the nursery separately, while with container size two, their height in the first year after planting had a positive relationship with their height, root collar diameter, root and total biomass in the nursery, while the root collar diameter in the first year after planting was positively correlated with total biomass in the nursery, suggesting that seedling quality significantly influenced the field growth performance of C. hystrix seedlings within first two years after planting.[Conclusion] The interaction of container size and medium had a profound effect on the seedling growth of one-year and two-year-old C. hystrix seedlings, therefore the optimum medium should be selected according to different seedling ages and container sizes. Container size one (8 cm×12 cm, diameter×height) and medium ten (50% composted bark, 25% yellow soil and 25% surface soil) were recommended to raise one-year-old C. hystrix seedlings, while container size two (12 cm×15 cm, diameter×height) and medium seven (50% composted bark and 50% surface soil) were suggested to raise two-year-old ones according to the seedling growth performance in nursery and after planting. It could be preliminarily concluded that under weed-controlled site, the field performance of one-year-old C. hystrix seedlings with container size one in the second year after out-planting was better than those of two-year-old seedlings with container size two in the first year after planting.

[Objective] The maximum outer and inner (defoliation part) crown shape predicted models for Larix olgensis plantation were developed based on the easily measurable individual tree variables to provide suitable approach to estimate crown surface area, crown volume and crown biomass for L. olgensis plantation.[Method] Using branch analysis data of 49 trees from Mengjiagang forest farm in Heilongjiang Province, the models of maximum outer crown and inner shape were developed. Outer crown shape predicted model constructed the continuous segmented equation with constraints and biological reasoning by employing the segmented regression technology. The outer crown radius equaled "0" at the tree tip and the inflection point where crown radius got maximum value was unique. Different from outer model, the straight line was used to model the inner crown shape. The relationships between the estimated parameters and tree variables were analyzed and the most intimate variable or variables combination were included in the models. The best models were selected as the basic model to develop the one level mixed effect model for the outer and inner crown shape. Based on the fixed effect of models, the outer and inner crown shapes were simulated.[Result] Diameter at breast height (DBH), tree height to diameter ratio (HD), crown length (CL) combined with crown ratio (CR) would predict the outer crown shape with the high accuracy. While the inner crown shape was modeled as DBH, HD and CL. The predicted accuracy was significantly increased by using 1 level (plot) mixed effect models compared with the basic models based on the goodness-of-fit and validation criteria. The coefficients of determination (R²), RMSE and average bias (Bias) of outer crown shape predicted model were 0.914 2,0.232 7 m,0.001 2 m respectively and 0.723 5,0.147 0 m,-0.000 034 m for the inner crown shape predicted model,respectively. Compared to the basic model, R² increased,while RMSE and Bias decreased for the mixed effect model. The segmented polynomial can reflect the variation regularity of the inflection point within the entire crown. The radii of the outer crown shape increased with the increase of DBH and CL, and decreased with HD and CL while other variables kept constant. The radii of inner crown shape increased with DBH, HD and CL.[Conclusion] The segmented polynomial equation with biological reasoning and linear model could effectively reflect the outer and inner crown shape. The models which possessed the random effect have improved the prediction accuracy and heteroscedasticity features of the models. Based on the fixed effect, the model could give reasonable simulation to the outer and inner crown shape. The segmented polynomial equation was flexible to describe the movement regularity of inflection points within the entire crown. Singular linear model performed well in modeling inner crown shape.

[Objective] The periodical information of forest areas in the high spatial resolution remote sensing image contains the structural and spatial distribution of forest canopy grains.We used the Fourier-based textural ordination (FOTO) indices for estimating forest aboveground biomass (AGB). This research explored FOTO textural indices as a potential technique to estimate forest AGB of temperate forest.[Method] The study area is located in the Liangshui Natural Reserve (47°11'N, 128°53'E), northeast of China. Based on the high spatial resolution airborne CCD data (0.5 m spatial resolution) acquired in September 2009, we derived the FOTO indices from CCD data and established the AGB regression model with multiple stepwise regression. The airborne LiDAR-derived AGB map was used as reference value. We compared the model performances of FOTO indices derived from three spectral reflection bands of CCD data with those from the average spectral reflection band of the CCD data. The window sizes for FOTO method were set as 60 m×60 m, 80 m×80 m, 100 m×100 m, 120 m×120 m and 150 m×150 m. Then the FOTO indices derived from different size windows were used as independent variables to build regression model with LiDAR-derived biomass. Ten-fold validation was performed to verify the generalization capability of the estimation model.[Result] The results showed that texture indices derived from FOTO method had a high correlation with forest AGB. The determination coefficient R² between the FOTO indices (9 FOTO indices from three spectral reflection bands) and LiDAR derived AGB were all above 0.67 for five windows sizes. The estimation accuracies were 67.3%, 73.4%, 74.4%, 78.3% and 80.9% for window size 60 m×60 m, 80 m×80 m, 100 m×100 m, 120 m×120 m and 150 m×150 m, respectively. The determination coefficient R² between the FOTO indices (3 FOTO indices from the average band) and LiDAR derived AGB were all above 0.57 for five windows sizes. The estimation accuracies were 58.2%, 62.1%, 64.3%, 67.4% and 70.9% for five windows sizes, respectively. We produced a wall-to-wall forest AGB map with the accuracy of 74.41% and the RMSE of 50.55 t·hm^-2.[Conclusion] This study results indicated that texture indices derived from FOTO method have great potential in estimating forest AGB without significant saturation phenomenon in temperate forests. FOTO indices have great potential for estimating AGB of temperate forests. The forest biomass derived from FOTO indices with the multiple stepwise regression showed a good relationship with the LiDAR-derived AGB, with R²=0.81, RMSE=46.78 t·hm^-2.

[Objective] The phytoplasmas in 16SrI group cause severe diseases of many crops and ecological plants in China. At present, the genetic variation and population structure of the yet-uncultured and very closely related phytoplasma strains in China are still not fully understood. A multilocus sequence analysis (MLSA) scheme was used to elucidate genetic diversity of phytoplasma strains in 16SrI group from different regions in China and their relationships with geographical distribution, and to compare the levels of variation in different housekeeping gene of different phytoplasma strains. The study aimed to provide some reference approach and evidence for finer detection, identification, classification and phylogenetic analysis of different phytoplasma strains in China.[Method] Ten housekeeping gene (rp, tuf, secA, secY, ipt, dnaK, fusA, gyrB, pyrG and rpoB) fragments combined with 16S rDNA sequences were employed to analyze the genetic variation and phylogenetic relationships of 18 phytoplasma strains infecting chinaberry, lettuce, mulberry, paulownia and periwinkle from ten provinces in China, using five phytoplasma strains, onion yellows phytoplasma (OY-M), aster yellows witches'-broom phytoplasma (AYWB), Candidatus Phytoplasma australiense (CPA), strawberry lethal yellows phytoplasma (SLY) and Candidatus Phytoplasma mali (CPM), of which whole genomes have been sequenced, as references. Sequence polymorphism and variation levels of different gene fragments were analyzed by multiple sequence alignment.[Result] The nucleotide site polymorphisms of rp, tuf, secA, secY, ipt, dnaK, fusA, gyrB, pyrG and rpoB gene fragments were used to resolve all strains into 15 sequence types (STs), demonstrating extensive genetic diversity among the 16SrI group strain population. All the strains, classified into 16SrI-B and -D subgroup by 16S rDNA analysis, were clustered into one clade and clearly differentiated into discrete subclades by phylogenetic analysis of the concatenated gene sequences. Ten chinaberry witches'-broom strains, which were most closely related to two mulberry dwarf strains and hardly distinguished with 16S rDNA, were definitely split into four distinct clusters and 8 STs apparently relative to their geographical origins. Two lettuce yellows strains in Sanming, Fujian province, China, were more closely related to the onion yellows OY-M strain in Japan than the periwinkle virescence and paulownia witches'-broom strains in China. The levels of variation in dnaK locus were higher than those in 16S rDNA and other genes tested.[Conclusion] It is suggested that the MLSA should potentially be a useful and reliable approach for phytoplasma identification and differentiation as well as for depth examination of strain diversity and this method can be wildly used to study the genetic variation and evolutionary relationships of phytoplasma strains among various groups or subgroups in the future.

[Objective] The fall webworm (Hyphantria cunea) is an invasive species, and has been causing severe damage to forestry and agricultural production. It is urgently needed to effectively control the pest population by an environmentally-benign technique. To reveal the mechanism of its strong migration capability which plays an important for its spreading, we analyzed the function of Wnt-1, an essential gene in wing development, by using the genome editing method.[Method] The full length cDNAs of HcWnt-1 were obtained by using the primers designed based on the genome data and transcriptome data of H. cunea. Online softwares was used to predict the structure characteristics of HcWNT-1 protein. RT-PCR and Immunohistochemistry were used to explore the expression pattern of HcWnt-1. The CRISPR/Cas9 was applied to induce mutations of HcWnt-1, the phenotypic and genotypic characteristics of embryonic mutants were observed, and further direct sequencing were used to detect the mutation events.[Result] The complete coding sequence of HcWnt-1 is 1 221 bp, which encodes a protein of 407 amino acids, characterized by helix-turn-helix DNA binding motif and 24 cysteine residues, and the highly conserved motifs are scattered throughout the sequence. During the embryogenesis stages, HcWnt-1 mRNA was highly expressed at early stage, WNT-1 protein expression showed sequential change during the embryonic development stages. The early embryos formation was completed in 24 h, at which the first peak was detected at transcriptional level and the HcWNT-1 expression was mainly concentrated in acron. The expression of HcWnt-1 declined as development progressed and the expression of HcWNT-1 elongated from head to tail along the anterior-posterior body axis. HcWnt-1 expression presented the second peak at 144 h, which occured in the appendages. CRISPR/Cas9-based mutagenesis of HcWnt-1 led to a high mortality rate (99.8%) and a mutation efficiency of 62.5% at embryonic stages following injection of Cas9 mRNA and sgRNAs with 1 000 eggs. Defective phenotypes as missing segments and appendages were observed in unhatched larvae.[Conclusion] The results have revealed that the segmentation model of H. cunea belongs to short and intermediate germ band. CRISPR/Cas9 system is a powerful genome manipulation tool in the invasive pest, and would be a promising tool for gene functional research in forestry and non-model insects. Loss-of-function of HcWnt-1 inhibited the segmentation and appendage development, demonstrating that HcWnt-1 plays an important role in embryonic development of H. cunea. Furthermore, HcWnt-1 was proved as a lethal gene, and it could be used as an appropriate target for future genetic control of H. cunea.

[Objective] Influences of typical vegetation communities in desert ecosystems on the aeolian activities in the near surface were studied to reveal soil wind erosion characteristics of desert ecosystem under different underlying surface conditions.[Method] Five typical underlying surfaces, including semi-fixed dunes (coverage 20%) of Artemisia ordosica, semi-fixed dunes (coverage 30%) of Nitraria tangutorum, fixed dunes (coverage 40%) of A. ordosica and fixed dunes (coverage 40%) of N.tangutorum, and mobile sand dunes (served as the control), were selected in the desert-oasis ecotone at the northeast margin of the Ulanbuh desert. By using the wind erosion brazing and sand flow acquisition system, five kinds of underlying surfaces wind erosion dynamic were real-time monitored to quantitatively analyze the differences of soil wind erosion, vertical distribution and grain size composition under the different underlying surface conditions.[Result] Soil wind erosion thickness on different underlying surface during the same period in Ulanbuh desert was mobile sand dunes > semi-fixed dunes of A. ordosica > semi-fixed dunes of N. tangutorum > fixed sand dunes of A. ordosica > fixed sand dunes of N. tangutorum. Sand peristalsis could be observed in mobile sand dunes when the wind speed reached to 4.1 m·s^-1, and the wind erosion material was able to be collected when the wind reached to 5.1 m·s^-1.In semi-fixed dunes of A. ordosica, semi-fixed dunes of N. tangutorum, fixed dunes of A. ordosica and fixed dunes of N. tangutorum, the wind erosion happened when wind speed reached to 6.3, 6.5, 6.8 and 7.9 m·s^-1, respectively. In the vertical section of 0-100 cm on the five bed surfaces, sediment runoff of 67.6%-90.0% distributed in 30 cm height, carrying airflow in the transport rate expressed as a power function declined with the increase of height, and increased with the increase of wind speed. The grain size composition of the wind erosion in each layer was in a unimodal distribution, with the peak between 250-100 μm; The peak value of the grain size composition in 0-20 cm height layers was obviously different from that of the other layers, and tended to be larger. From below to top, the proportions of very fine sand particles showed an increasing trend, but the proportions of medium sand grain size showed a decreasing trend.[Conclusion] With the increase of vegetation coverage, soil wind erosion decreased significantly, and the annual wind erosion depth of mobile sand dunes, semi-fixed dunes and fixed sand dunes decreased. With coverage of 40% A. ordosica and N. tangutorum community, the soil wind erosion depth was only about 1.73%-1.52% of the wind erosion depth of mobile sand dunes at the same time, and the sediment transport rate in the range of 0-100 cm height was only 6.6%-5.1% transport rate of mobile dune sand. Vegetation alleviated stream erosion to the surface mainly by covering the surface, increasing the roughness of the underlying surface and blocking the movement of sand. Therefore, in the process of implementing anti-desertification project, we should fully consider and use the ecological effects of vegetation in resisting wind erosion.

[Objective] Electric resistance tomography, stress wave imaging and resistograph were employed to detect and quantitatively characterize the internal decay for standing trees,then these three NDT(nondestructive testing)techniques were made comparisons in order to find out the appropriate technique matched with specific condition of standing trees in the forest field.[Method] An investigation about the accuracy of different NDT methods was carried out in the experiment forest of Northeast Forestry University in Harbin, Heilongjiang Province. 100 cross-sections of Fraxinus mandshurica and Populus×beijingensis standing trees were tested by four methods:electric resistance tomography, stress wave tomography, resistograph and estimation weight loss ratios of wooden increment cores. Taking wood core samples as research objects, testing results of three other kinds of NDT methods were compared. E_s determined by estimating weight loss ratios of wooden cores was regarded as the truth value of decay extent. Using ordinary least square regression to analyze the relationship between E_s and E_d(degree of decay determined by electric resistance tomography),E_s and E_y(degree of decay determined by stress wave),E_s and E_z(degree of decay determined by resistograph).[Result] Results showed that three NDT methods were able to estimate the different degree of decay for Fraxinus mandshurica and Populus×beijingensis standing trees; As a whole, the fitting degree of E_d and E_s, E_y and E_s were both lower than that of E_z and E_s. In different decay degree, when E_s<30%, E_d had a strong positive correlation with E_s(R=0.823,P<0.01), while when 30%≤E_s<50%, E_y have a significant positive correlation relationship with E_s(R=0.658,P<0.01), electric resistance tomography had more sensitively reflect in incipient decay of standing trees, and stress wave had more accurate diagnosis on detecting middle decay of standing tress. E_z had a strong positive correlation relationship with E_s, and when E_s≥50%, E_z have a more positive correlation relationship with E_s(R=0.914,P<0.01).[Conclusion] Electric resistance tomography showed better diagnosis than the other two methods for incipient decay of standing trees, while stress wave imaging method used in the middle stage of decay testing was best, and resistograph can be used in the different stages of decay. It was suggested that each technique could be employed in the practical internal decay testing for standing trees according to the decay stage and operational conditions.

[Objective] In order to improve the durability of exterior wood treated by triazole formulations, the leachability of 5 kinds of emulsified triazoles and their copper triazole formulations was analyzed and compared.[Method] According to the procedures of GB/T 29905-2013, the leaching properties of 5 kinds of triazole micro-emulsion and their copper amine formulations were determined and compared,and the leaching properties of triazole formulations with 4 kinds of waterproofing agents were also conducted in this paper.[Result] The fixation rates of propiconazole (PPZ) and hexaconazole (Hex) were above 70%, and higher than those of other triazoles. The fixation rate of tebuconazole(TEB)was slightly lower than that of PPZ and Hex. The fixation rate of cyproconazole(CY)in treated wood ranged from 60% to 70%, while that of triadimenol (Tri) was less than 60% at the highest retention. There was no significant difference in fixation rate between any two of the same kind of triazoles with different emulsified formulations. After mixed with copper amine, the fixation rates of triazoles were improved and higher than 80%, whereas the fixation rate of copper of Cu amine/triazoles formulations was more than 90%.[Conclusion] The fixation rates of propiconazole (PPZ) and hexaconazole (Hex) were above 70%. The different emulsifiers had less effect on the leachability of triazoles. The fixation rates of triazoles in treated wood could be improved when mixed with copper amine or brushed with waterproofing agents on wood surface.

[Objective] This article investigated the influence of topographic factors on leaf traits of different forest plant communities in Daqinggou Nature Reserve in order to reveal the main driving topographic factors that influence the leaf functional traits.[Method] Ulmus macrocarpa, Quercus mongolica, and Fraxinus mandshurica in Daqinggou Nature Reserve were selected as research objects. Each community type was set five fixed sample plots of 20 m×20 m. In the plots the leaves of the species whose important values were greater than 0.1 were collected. The leaf thickness, the specific leaf area, the leaf dry matter content, the leaf size and the leaf dry mass of the dominant species in different community types were measured. The Pearson correlation analysis and stepwise regression analysis were used to study the relationship between the different leaf traits of dominant species in the different community types and topographical factors.[Result] The Pearson correlation analysis showed that there was a significant negative correlation between the specific leaf area and altitude, and a significant positive correlation between the specific leaf area and the slope position. There was significant positive correlation between leaf dry matter content and altitude, and a significant negative correlation between leaf dry matter content and the slope position, regardless of all the dominant species or the different growth forms. The stepwise regression analysis further indicated that altitude was the primary factor influencing all the leaf traits except leaf size of all the dominant species, leaf thickness and leaf dry mass of shrub species, and leaf thickness of herb species, which were influenced by slope position and the standard partial regression coefficient was 0.259, -0.508, -0.467 and 0.410, respectively. The standard partial regression coefficient was 0.285, -0.438, 0.504 and 0.146 respectively for the leaf thickness, the specific leaf area, the leaf dry matter content and the leaf dry mass of all the dominant species; standard partial regression coefficient was 0.494, -0.378, 0.563, 0.836 and 0.575 respectively for the leaf thickness, the specific leaf area, the leaf dry matter content, leaf size and leaf dry mass of tree species; standard partial regression coefficient was -0.336, 0.490 and 0.171 respectively for the specific leaf area, the leaf dry matter content and the leaf size of shrub species; standard partial regression coefficient was -0.555, 0.650, -0.357 and -0.271 respectively for the specific leaf area, the leaf dry matter content, the leaf size and the leaf dry mass of herb species.[Conclusion] Although the altitude difference is only sixty to seventy meters in Daqinggou nature reserve, the soil moisture obviously reduced with the increasing altitude. The change of soil moisture influenced the community composition. The difference in the community composition caused the changes in leaf functional traits. Thus altitude is the main driving factor that influences the leaf traits.

[Objective] This paper puts forward a new method for identifying burned areas and fire intensity by using Landsat TM images and RS indices to construct the decision tree classification model. In combination with topographic factors such as slope, aspect and elevation the spatial distribution of fire severity was scientifically and systematically analyzed in this study to provide theoretical basis and data support for forest fire prevention and management in Daxing'anling Mountains.[Method] In this paper, Huzhong region of the Daxing'anling Mountains was targeted. TM images of post-fires in September 2010 and September 2007 were taken as the basic data, and DEM images and forest type maps were used as the auxiliary data. The NDVI, NDSWIR, MNDWI, dNBR and other RS indices were employed to build a decision tree classification model which then was used to identify ten burned areas of Huzhong in 2010. Fire severity was divided into four classes according to the threshold value of dNBR, and the Arcgis software was used to do an overlaying analysis on the fire severity map with slope, aspect, elevation.[Result] The overall accuracy and Kappa coefficient of the decision tree classification were 97.97% and 0.943 2. Compared with the Parallelepiped method and ISODATA method, the total classification accuracy was increased by 7.56% and 17.32%, respectively. The Kappa coefficient was also increased. In the decision tree method, the producer's accuracy and user's accuracy were 97.51% and 97.54%, the Parallelepiped method were 90.43% and 96.52%, and the ISODATA method were 94.35% and 95.68%. Fire severity was divided into four classes according to the threshold of dNBR:unburned, low, moderate and high. Moderate severity burned area accounted for 46.6% of the total, and high severity burned area was 33.2%. After overlaying analysis, 64.4% (4 177 hm²) of burned area located at the elevations from 1 000 m to 1 500 m, and 45.9% of burned area located at level Ⅲ slope (6°-15°). The burned area at the southern slope occupied 21.4% (1 391 hm²) of the total.[Conclusion] The decision tree classification model presented in this paper could identify burned areas accurately and the total classification accuracy was higher than the parallelepiped method and ISODATA method, and the burned area is closer to the method of visual interpretation. Moderate and high severity burned areas occupied most of the total burned areas, and there were some relations between the burn severity and slope, aspect, elevation.