Objective: Under natural conditions, Quercus variabilis seeds have uneven emergence. This study monitored the characteristics of seed germination and emergence of Q. variabilis day by day, explored the characteristics of seed germination and emergence of Q. variabilis and its own physiological and biochemical change process, analyzed the mechanism of irregular emergence, and provided theoretical support for accurate regulation of seedling quality. Method: Through the dynamic observation of the germination and emergence process of Q. variabilis seeds, according to the characteristics of seed morphological changes and emergence statistics during the germination and emergence process of Q. variabilis seeds, the germination and emergence process of Q. variabilis seeds was divided into stages and periods, and the physiological and biochemical changes of Q. variabilis seeds germinated and emerged at different stages and periods were measured, The activities of peroxidase (POD) and superoxide dismutase (SOD) were determined by plant physiological method, the contents of gibberellin (GA₃), indoleacetic acid (IAA) and abscisic acid (ABA) were determined by high performance liquid chromatography, and the contents of soluble sugar and starch were determined by anthrone colorimetry, α- amylase and β- amylase was determined by 3, 5-dinitrosalicylic acid colorimetry. Result: 1) Q. variabilis seeds began to germinate on the 6th day after sowing, and ended on the 33rd day. The germination cycle was 27 days, and the cumulative germination rate was 73.6%, of which the median germination was 14 days. Q. variabilis seeds began to emerge on the 21st day after sowing and ended on the 60th day. The emergence cycle was 40 days, and the cumulative emergence rate was 66.6%, of which the median emergence was 29 days. The emergence process of Q. variabilis seeds can be divided into three periods. When the average daily emergence rate of Q. variabilis seeds exceeds 3%, it is the emergence peak (25-30 days after sowing), which accounts for 10% of the whole emergence cycle. During this period, the number of seedlings accounts for 44% of the total number of seedlings; Before this period, the emergence stage is the rising stage (1-24 days after sowing), accounting for 40% of the whole emergence cycle, and the number of emerging seeds accounts for 11% of the total number of seedlings; The peak period is followed by the emergence decline period (31-60 days after sowing), accounting for 50% of the whole emergence cycle, and the number of emergence seeds accounts for 45% of the total number of emergence. 2) In the process of Q. variabilis seed germination, the POD activity in the first germinated Q. variabilis seed is higher. In the process of Q. variabilis seed emergence, the pod and SOD activities in the seed are higher when the number of seeds is large. 3) Compared with germinating seeds, GA₃ increased by 64%, ABA decreased by 30.3%, soluble sugar content decreased by 51% and starch content decreased by 24.1%, α-amylase activity decreased by 45%, while β- amylase activity increased by 67.7%. Conclusion: The germination and emergence of Q. variabilis seeds are two independent processes, and some seeds have germinated but not emerged in the end. The long period from seed germination to seedling emergence and large individual differences are the main factors leading to uneven seedling emergence of Q. variabilis while seed dormancy of Q. variabilis is different among individuals, and the seed germination cycle is long, which is also one of the reasons for the uneven emergence of Q. variabilis seeds; POD and SOD mainly affected the germination stage of Q. variabilis seeds; GA₃ and IAA promoted the emergence of Q. variabilis seeds. The higher the content, the faster the emergence rate; ABA inhibited the emergence of Q. variabilis seeds.

Objective: The seed germination of pond cypress is slow, uneven andthus leading to a low seedling rate, which brings certain difficulties to production management. The present study is to identify the causes of seed dormancy of pond cypress by studying the relationship between seed coat and seed dormancy, so as to provide a theoretical basis for the practical application of pond cypress seed and a technical guidance for ecological restoration in the Three Gorges Reservoir area. Method: The relationship between seed coat and seed dormancy of pond cypress was studied through observing the structure of seed and seed coat, germination test, TTC activity test, water permeability test, extraction and bioassay of endogenous inhibitors in different parts of seeds, as well as extraction, separation and bioassay of inhibitors contained in seed coat. Result: 1) The seed coat of pond cypress from outer to inner in order is: epicuticle, sarcotesta, sclerotesta, and endotesta. Compared with the control, the hot water treatment could promote the abscission of epicuticle, but had no obvious effect on the structure of seed coat, and the seed coat permeability had no obvious change. After 15 minutes of acid treatment, corrosion cracks and pits appeared on the seed surface, the structure of seed coat was damaged, the seed coat became thinner and the seed coat permeability increased; After 30 minutes of acid treatment, a large number of corrosion cracks and pits appeared on the surface of seed coat, which further damaged the seed coat structure while enhancing the seed permeability. 2) The viability of newly harvested pond cypress seeds was at 80.95%, but the seeds did not germinate and had significant dormancy. 3) The seed coat of pond cypress has a certain degree of water permeability, and the kernel can absorb part of the water. Although the acid treatment is conducive to promoting the seed kernel to absorb water, the hard seed coat hinders the water absorption and expansion of the kernel to a certain extent, which makes the kernel absorb water slowly, and may produce mechanical resistance to the elongation and growth of the radicle. 4) The seeds of pond cypress contain endogenous inhibitors. The inhibition intensity of methanol extracts from different parts on seedling and root growth was as follows: seed coat > kernel. The result showed that the inhibitive substances mainly existed in the seed coat instead of seed kernel. 5) The methanol extract from seed coat of pond cypress was separated and bioassayed by systematic separation method. The result showed that the methanol extracts from seed coat inhibited the growth of Brassica chinensis seedlings at different degrees. When the concentration of each separation phase was 1 g ·mL^-1, the inhibition intensity of Brassica chinensis seedling height was petroleum ether phase > ethyl acetate phase > ether phase > methanol phase > aqueous phase, and the inhibition intensity of Brassica chinensis root length was petroleum ether phase > methanol phase > water phase > ethyl acetate phase > ether phase. Petroleum ether phase and methanol phase are the main phases with inhibitory effect. Conclusion: The water permeability of seed coat of pond cypress may not be the main factor causing seed dormancy, but the mechanical restraint of seed coat may lead to slow seed germination. The inhibitory substances in seed coat of pond cypress are mainly concentrated in petroleum ether phase, whose components are characterized with smaller polarity molecules. Therefore, the structure of seed coat and endogenous inhibitors are the main causes of seed dormancy. The seed of pond cypress may take on a comprehensive dormancy (combinational dormancy, PY+PD) with both physical and physiological dormancy traits.

Objective: Imbibition is the initial and most important stage of seed germination. Nuclear magnetic resonance (NMR) technology was used to explore the initial water absorption site and the spatial and temporal movement of water throughout the seed after hot water treatment from the perspective of time and space, revealing the changes of water phase in seeds. Thisprovides a new method for the study of water absorption in seeds. Method: The seeds of A. julibrissin were treated with hot water at an initial temperature of 80 ℃. The water absorption was calculated by the increase in weight after soaking divided by the initial weight. MRI technology was used to observe the initial water absorption location and the movement of water in the seeds after water absorption, combined with T₂ relaxation detection technology to explore the dynamic changes in phase and state of the water. Result: 1) The water absorption curve of A. julibrissin seeds exhibited an "S" type behavior, where the water absorption of seeds increased slowly in the early stage (0-4 h); the seeds entered the rapid water absorption stage during 4-12 h, where the water absorption increased greatly; finally the seeds entered the slow water absorption stage at 12 h. During the process of water absorption, the MRI result of the seeds showed that the water initially entered the seeds from the micropyle, then migrated inside the seed through three paths, namely: ①The water moved along the vascular bundle at the seed coat toward the chalazal; ② The water moved down towards the chalazal through the gap between the seed coat and cotyledons, entering the lateral side of cotyledons; ③ The water entered the hypocotyl through the radicle, then entered the cotyledons and moved to the chalazal, but its moving speed was noticeably slower than that of the second path. At the initial stage of water absorption (0-6 h), the imbibition area of the right seed coat was significantly larger than that of the left. Later, with the extension of soaking time, the imbibition speed of the left seed coat was faster, and there was no significant difference between the imbibition area of the left seed coat and that of the right seed coat. 2) The NMR spectrum showed that the water content (X) of A. julibrissin and the peak area (S) had a linear relationship, and the linear regression equation was: S=21 132X+695.05, R²=0.999 6. 3) There were three main states of water in A. julibrissin seeds, namely bound water, cytoplasmic bulk water, and extra-cellular free water. 4) At 0 h, bound water accounted for 45.13% of the water in the cell, extracellular free water accounted for 53.51%, and cytoplasmic bulk water was almost absent. During the process of water absorption, the content of bound water decreased significantly, which continued to decrease, accounting for only 2.08% by 48 h; the content of cytoplasmic bulk water increased rapidly at first and then decreased gradually. The content of extra-cellular free water increased continuously. At 48 h, the percentages of cytoplasmic bulk water and extra-cellular free water were 29.12% and 68.80%, respectively. During the whole process of water absorption, the percentages of water phases in three states was always in dynamic change, and the content of extracellular free water was much higher than that in other states. During this water absorption process, the peak of extra-cellular free water and bound water shifted to the left. Conclusion: The micropyle is the initial sites of water absorption in the seeds of A. julibrissin seeds. The water moves through the seed via the seed coat on both sides, the gap between the seed coat and the cotyledon, and the hypocotyl, and moves towards the chalazal. During the process of water absorption, there are three different water phases, namely bound water, cytoplasmic bulk water, and extra-cellular free water in the seeds of A. julibrissin, and they transform into each other during the entire imbibition process, which prepares the seed for germination.

Objective: The study was intended to evaluate the effect of different diameter-classes of Larix principis-rupprechtii on diversity pattern of neighbor species at different scales for coniferous-broadleaved mixed forest dominated by L. principis-rupprechtii in the National Nature Reserve of Xiaowutai Mountains of Hebei, and clarify the effect of different ecological processes on the formation of diversity pattern of neighbor species of the L. principis-rupprechtii to contribute to a better understanding of the mechanism of maintaining species diversity. Method: In the National Nature Reserve of Xiaowutai Mountains of Hebei, a 2.4 hm² (80 m × 300 m) plot for monitoring forest dynamics was established in a typical coniferous-broadleaved mixed forest, and species composition and community structure were analyzed. Based on the distribution of DBH (Diameter at Breast Height) for all individuals, all individuals of dominant species L. principis-rupprechtii were divided into nine DBH classes with a spacing of 3 cm to explore the effect of L. principis-rupprechtii within different diameter-classes on of neighbor species using the individual species-area relationships (ISARs) combined with the heterogeneous Poisson null model. Result: There were 4 275 independent individuals with DBH ≥ 1 cm, belonging to 35 species 26 genera 17 families. The structure of L. principis-rupprechtii within each diameter-class all showed approximately normal distribution, in which diameter-class V (19-22 cm) had the largest number of individuals (92). Within a scope of 30 m, the ISARs(r) values of L. principis-rupprechtii of the nine diameter-classes all displayed a increasing tendency with increase of the scope. In addition, ISARs(r) curves of IV (16-19 cm) and IX (≥ 31 cm) diameter-classes showed both maximum and minimum values for all the scopes. L. principis-rupprechtii displayed a neutral impact on the diversity pattern of neighbor species for the three diameter-classes III (13-16 cm), VII (25-28 cm) and VIII (28-31 cm) for all the scopes. Promotional or inhibitory impacts on the diversity of neighbor species all occurred in the small scopes and changed to neutral with increase of the scope. Among the small scopes, five diameter-classes I (< 10 cm), II (10-13 cm), IV, V and VI (22-25 cm) of L. principis-rupprechtii showed promotional impact to some extents, and only diameter-class IX showed an inhibitory impact at the scope of 2-4 m. Conclusion: The scope-dependent impact of L. principis rupprechtii significantly affected the diversity pattern of neighbor species. Although the neutral impact of L. principis-rupprechtii on diversity pattern of neighbor species was the dominant process for different diameter-classes at multiple scales, the promotional impact of L. principis-rupprechtii on the diversity pattern of neighbor speceis at smaller scales is not ignoreable. The IV and IX diameter-classes of L. principis-rupprechtii are the two key growth stages for the formation and maintenance of the diversity pattern of neighbor species.

Objective: Based on the data of permanent monitoring plots of the successive national forest inventories, a multi-factor forest growth model was constructed through the machine learning algorithm, which improves the simulation accuracy of forest growth and carbon sequestration, predicts the future carbon sink potential of arbor forests of the three provinces in northeast China, and explore the potential distribution of arbor forest carbon sink. It provides a scientific guidance for accurately locating the role of forests in northeast China in increasing sinks and reducing emissions, and scientifically formulating the national "Carbon Neutral" action path and target management. Method: Based on the data of permanent monitoring plots of the successive national forest inventories from 1999 to 2018, and combined with multiple influence factors such as regional climate, soil, forest stand and topography, etc., we used the random forest algorithm to construct a growth-loss model of the main dominant tree species (groups) in the region. Combining the future climate and arbor forest area expansion scenario, the biomass carbon stock (BCS) and BCS changes of arbor forests of the three provinces in northeast China from 2015 to 2060 were predicted. Result: The BCS of arbor forests of three provinces in northeast China reached 3 393.15 TgC in 2060, an increase of 1 895.23 TgC compared with that in 2015, and the annual mean BCS changes was 42.12 TgC ·a^-1 during 2015-2060. Natural forests played the major role in the BCS and BCS changes. The BCS of arbor forests in Liaoning, Jilin, and Heilongjiang will be increased from 139.19, 463.58, and 895.15 TgC in 2015 to 328.95, 915.83, and 2 148.37 TgC in 2060, respectively. The average biomass Carbon Density (BCD) of arbor forests will be increased from 32.71, 59.75, and 45.11 t ·hm^-2 in 2015 to 75.20, 109.32, and 85.24 t ·hm^-2 in 2060, respectively, and the average annual biomass carbon sinks of arbor forests in Liaoning, Jilin, and Heilongjiang from 2015 to 2060 are 4.22, 10.05, and 27.85 TgC ·a^-1, respectively. Conclusion: The random forest model constructed in this study performs well and can be used to predict the future BCS of arbor forests of three provinces in northeast China. From 2015 to 2060, the BCS of arbor forests of three provinces in northeast China will be increased by 1 895.23 TgC, which will still have a large carbon sink potential in the future. Heilongjiang Province has the largest carbon sink potential, with an annual increase of carbon storage up to 27.85 TgC ·a^-1, which is an important carbon sink area in the future; while Liaoning Province is weaker, with an annual increase of carbon storage by only 4.22 TgC ·a^-1. Strengthening the management of the young and middle-aged forests, moderately regenerating the mature and over-mature forests, and enhancing the carbon sink function of arbor forests of the three provinces in northeast China will help to improve the role of forests in achieving the goal of "Carbon Neutral".

Objective: The objective of this study was to assess the early influence of plantations with different local tree species on the compositions of soil aggregates and their organic carbon and nitrogen concentrations and storage. This study was designed to provide more theoretical basis for rational selection of tree species in afforestation and forest management in subtropical China. Method: A common-garden planted with dominated tree species in central subtropical China was established in a forest stand with the same parent material and forest management through a randomized block design in February 2012. Soil samples were collected at different soil layers (0-10, 10-20, 20-30, 30-40, and 40-50 cm depths) at plantations of six tree species (Schima superba, Castanopsis carlesii, Elaeocarpus decipiens, Cinnamomum camphora, Cunninghamia lanceolate and Pinus massoniana) in August 2019. The particle size compositions (>2, 1-2, 0.25-1, and 0.053-0.25 mm), and their carbon and nitrogen concentrations, storage and carbon to nitrogen ratios were determined. Result: 1) The dominated aggregate mass percentage was observed in >2 mm particles in all soil layers, and the mass percentage of >2 mm particles decreased with increasing soil depth. The mass percentage of >2 mm particles were the highest in soils planted with Castanopsis carlesii, whereas the mass percentages of 1-2, 0.25-1, and 0.053-0.25 mm particles were the highest in soils planted with Pinus massoniana. 2) The organic carbon concentrations in aggregates of all particle sizes decreased with increasing soil depth and the organic carbon concentrations in aggregates increased but then decreased with the decreasing particle sizes at all of the studied soil layers. The organic carbon concentrations in aggregates were the highest in the 1-2 mm particles for 0-10 cm soil layers, while those were the highest in 0.25-1 mm particles for 10-20, 20-30, 30-40, and 40-50 cm soil layers, with the highest concentrations observed in soils planted with Castanopsis carlesii. 3) The nitrogen concentrations in aggregates were the highest in soils planted with Castanopsis carlesii and the lowest in soils planted with Cinnamomum camphora for all particle sizes and soil layers. 4) The patterns of organic carbon and nitrogen storage were consistent with the variations of the compositions of soil aggregates at all soil layers. The organic carbon and nitrogen storage in the >2 mm particles were the highest in soils planted with Castanopsis carlesii, while those in the other particles with sizes less than 2 mm were the highest in soils planted with Pinus massoniana except for the 0-10 cm soil layer. 5) The carbon to nitrogen ratios in all aggregates were higher in surface soils (0-20 cm) but lower in deeper soils (30-50 cm). Conclusion: The compositions of aggregates at all of the studied soil layers was dominated by >2 mm particles, and their mass percentage showed decreasing tendency towards deeper soils after 7 years of plantation for all tree species. The mass percentage of >2 mm particles was the highest in soils planted with Castanopsis carlesii, while those for other particles with sizes less than 2 mm were the highest in soils planted with Pinus massoniana. Meanwhile, the carbon and nitrogen storage in aggregates were strongly controlled by the mass percentages of soil aggregates than by their concentrations in these particles. The soils planted with Castanopsis carlesii had higher carbon and nitrogen storage than the soils planted with Pinus massoniana.

Objective: The rotation period of slash pine timber and resin plantations in China is appropriately extended on the basis of the mature age of timber plantations. Although certain economic benefits can be obtained in this rotation, there is still no scientific basis for whether the optimal economic benefits can be obtained. By analyzing the contribution of timber and pine resin to the economic performance of slash pine management, this study determined the time timeline of resin tapping and forest harvesting and the influencing factors, which can provide a scientific basis for maximizing the management benefit of slash pine plantations and the sustainability of forest product production. Method: Based on the production practice of slash pine plantations in Fengshushan forestry farm of Jingdezhen, Jiangxi Province, a Faustmann model was established to calculate the land expected value (LEV) in considering the yield of resin and output of timber. Then 1) the contribution of timber and resin to the income of slash pine plantations was clarified by comparing the income cash flow of timber and resin mixed use plantations and timber plantations; 2) The LEV and optimal rotation period (T^*) of the two types of slash pine plantations were compared under 4 different discount rates; 3) The sensitivity of LEV and T^* to the changes of these factors under the different discount rates was evaluated by setting the change range of the prices of timber, resin and operating costs. Result: 1) The nominal cash income of timber and resin plantations is higher, but if the management period is long enough, the nominal cash income of slash pine timber plantations and timber and resin plantations will converge. Although the resin income increased the LEV of stand, the contribution of timber income to the total nominal income will affect the change of LEV. 2) The T^* of timber and resin plantations is longer than that of timber plantations. If other conditions remain unchanged, the T^* of timber plantations will be shortened with the increase of discount rate, but the T^* of timber and resin plantations will be slightly prolonged. 3) The price of timber has a positive effect on LEV and T^* of slash pine timber plantations, but it has no obvious effect on T^* of timber and resin plantations when the price of timber decreases. The price of resin has a positive effect on the LEV of timber and resin plantations, but the effect on T^* is not obvious. Only when the discount rate is high, the price decreases and T^* decreases. Labor cost has a positive effect on T^* of timber plantations, but has no effect on T^* of timber and resin plantations. Conclusion: 1) Slash pine timber and resin plantations have stronger income generating capacity than timber plantations. The contribution of timber income to the total income of timber and resin plantations cannot be ignored. The management of slash pine plantations should aim at maximizing the total income of timber and resin, at the same time, the growth of trees should be considered. 2) The resin harvesting does prolong the T^* of slash pine plantations. However, under the current price level, if the discount rate exceeds 10%, forest management will be unprofitable. Therefore, low discount rate is beneficial to the long-term production of resin. 3) T^* of timber and resin plantations is not sensitive to the change of resin price, labor cost and lower timber price. From the perspective of investment, the profitability of slash pine plantations mainly depends on the discount rate. The effect of discount rate on T^* is related to the proportion of timber income in total stand income. The higher the proportion is, the greater the negative effect of discount rate on T^* is. 4) The determination of the starting time of resin tapping will affect LEV and T^* and the most appropriate time is when the stand is close to maturity. By then more resin is formed, and the effect of resin tapping on stand growth is gradually weakened.

Objective: This study aims to reveal the genetic structure and geographic variation characteristics of Liriodendron populations, in order to provide a basis for the conservation, utilization and improvement of genetic resources of Liriodendron. Method: A total of 97 samples derived from 9 provenances of Liriodendron chinensis and 46 samples derived from 4 provenances of L. tulipifera were collected. The SNP markers of the samples were identified by RAD-Seq sequencing. The observed heterozygosity (H_o), expected heterozygosity (H_e), nucleotide diversity (π), gene differential coefficient (G_st) and other genetic statistics were calculated to analyze the genetic diversity and genetic structure of Liriodendron provenances. Result: A total of 4 454 high quality SNP markers were identified in the 143 samples of Liriodendron. There were Liriodendron maintained moderate genetic differentiation and medium level gene flow among provenances of L. chinensis (G_st=0.241 9, N_m=0.805 1). There were large genetic differentiation and low level gene flow among L. tulipifera provenances (G_st=0.388 6>0.25, N_m=0.397 0). The 13 Liriodendron provenances were divided into 3 subgroups by population structure analysis. Among them, 9 provenances of L. chinensis were divided into eastern provenances (group 2) and western provenances (group 1), and the other provenances belonged to group 3 and they are all L. tulipifera. The order of genetic diversity was: group 3 > group 1 > group 2. Conclusion: The formation of genetic structure of Liriodendron is related to its geographical isolation and fragmented distribution, and there are endangered phenomena caused by small population effect and fragmentation. The SNP markers developed in this study can provide a reference basis for molecular identification, germplasm innovation and collection and preservation of germplasm resources of Liriodendron.

Objective: Many secondary metabolites in spina gleditsiae are medicinal active ingredients. This article aims to investigate the differential secondary metabolites in spines of Gleditsia sinensis and Gleditsia microphylla,and analyze the enrichment of the differential metabolic pathway,so as to provide a theoretical basis for the separation and identification of functional compounds from spina gleditsiae and for the research and development of functional compounds. Method: The 1-year-old spines of G. sinensis and G. microphylla were used as materials,the UPLC-MS/MS detection platform was used to determine secondary metabolites,and self-built database MWDB4.0 was used for metabonomic analysis. Results: 1) A total of 457 secondary metabolites were detected in the two species of spina gleditsiae,which were divided into 8 categories: phenolic acids,alkaloids,terpenes,flavonoids,lignans,coumarins,tannins,and others. Among them,phenolic acids and flavonoids accounted for a relatively large proportion; 2) There were significant differences in 213 metabolites in the spines between G. sinensis and G. Microphylla, of which the contents of 121 substances were higher in G. microphylla spines,including 55 phenolic acids and 54 flavonoids,5 kinds of lignans and coumarins,4 alkaloids,2 terpenes,and 1 other substance; The contents of 92 substances in G. microphylla were lower,including 21 phenolic acids,19 flavonoids,14 tannins,14 alkaloids,8 kinds of lignans and coumarins,16 others. 3) There were 22 kinds of unique metabolites in G. sinensis spines, of which isovitexin-2″-O-rhamnoside,N,N′-Diferuloylputrescine,diosmetin-8-C-(2″-O-rhamnosyl) glucoside,pterostilbene,and procyanidin C2 had relatively higher content. There were 27 unique metabolites in G. microphylla spines,of which the relative content of coniferin,5-O-Caffeoylshikimic acid,and quercetin-3-O-(2″-p-Coumaroyl) glucoside was relatively higher. 4) Metabolic pathway analysis of differential metabolites showed that the significantly differential metabolites in the pathways of "stilbene,diarylheptanes and gingerol biosynthesis" were significantly enriched,and the differential metabolites of phenylpropane biosynthesis and flavonoid metabolism were more enriched. Conclusion: There are 457 secondary metabolites detected in G. sinensis spines and G. microphylla spines. The differential metabolites are mainly concentrated in flavonoids and phenolic acids. The stilbenoid,diarylheptanoid and gingerol biosynthesis are significantly enriched in differential metabolites (P < 0.05),and the metabolites of phenylpropanoid biosynthesis and flavonoid biosynthesis are more enriched.

Objective: As a member of the pine wood nematode disease system, Bursaphelenchus mucronatus has caused serious ecological and economic losses in China due to its efficient and frequent mating behavior. We therefore investigated Bmu-gpa-1 gene of G protein that is related to mating behaviour, and its expression characteristics and its role in mating behavior in B. mucronatus, which would provide a basis for the study of the molecular mechanisms for mating and reproduction in B. mucronatus. Method: Bmu-gpa-1 gene was cloned by PCR based on the genomic data of B.mucronatus. The sequence alignment, phylogenetic analysis and protein structure prediction were conducted to clarify its evolutional relationship with other species. The RT-qPCR and in situ hybridization were used to analyze the gene expression level and expression location in different development stages to reveal its temporal and spatial dynamic expression characteristics. The gene Bmu-gpa-1 was silenced by RNAi to investigate the effects on mating behavior and reproductive capability. In the meanwhile, RT-qPCR was used to check the efficiency of RNAi. Result: The full-length of Bmu-gpa-1 gene is 1 780 bp, including 1 056 bp CDS, encoding 354 amino acids. Phylogenetic analysis indicated that the gene belonged to the same G protein alpha subunit family as gpa-1 in Caenorhabditis elegans. The results of RT-qPCR and transcriptomes showed that Bmu-gpa-1 was expressed in all developmental stages of B. mucronatus, with the expression level highest in the second and third juvenile stages, followed by embryonic stage, and the expression level in the fourth juvenile stage and the adult stage was the lowest. Meanwhile, we found the gene expression level has sexual dimorphism, showing a higher expression level in the males than that in the females. The result of mRNA in situ hybridization showed that Bmu-gpa-1 was expressed broadly in the nematodes. In the embryonic stage, expression location changed dramatically from sporadic dots to whole embryos. In the second juvenile stages, it was expressed in the whole bodies. In the third and fourth juvenile stages, it was mostly located in the intestinal tracts and gonads. In the adult stage, the expression location had sexual dimorphism, it was seen in the vulvas of females, whereas it was only observed in the spicules and tails in males. In the mating test, the males after silencing Bmu-gpa-1 had more frequent and faster mating behavior events than those of controls, but had fewer offspring. However, there were no significant changes in the mating and reproductive behavior of the RNAi-treated females. It is speculated that Bmu-gpa-1 gene can negatively regulate the mating behavior for males, but not for females. Conclusion: Bmu-gpa-1 is a member of the G protein alpha subunit family. It has sexual dimorphism in the expression level and location. Our result indicate the males treated by RNAi have stronger capacity in signal transduction and massive invalid frequent mating behaviors, but not happened in females. It is suggested that Bmu-gpa-1 plays a negative role in the signal transduction of male nematodes and regulates their mating behaviors and fecundity in B. mucronatus.

In this paper, a new species of Megabeleses fengyangshana Li, Liu & Wei, sp. nov. (Hymenoptera: Tenthredinidae), collected from Zhejiang, China is described. The larvae of this species feed on leaves of Liriodendron chinense and can cause serious damage to the plant. The new species is very similar to M. liriodendrovorax G. Xiao, 1993 in general appearance, but can be distinguished from the latter by the cell 2Rs in fore wing with a distinct stigmata and the mesepisternum densely punctured and mixed with microsculptures. Although the morphological differences are less distinct, the mitochondrial genomes of the two species are significantly different. The P-distances of atp6, atp8, cob, cox1, cox2, cox3, nad1, nad2, nad3, nad4, nad4l, nad5, nad6 between M. fengyangshana and M. liriodendrovorax are 11.1%, 13.6%, 10.3%, 7.6%, 6.5%, 7.0%, 6.4%, 11.6%, 7.4%, 7.5%, 5.2%, 6.4% and 7.2%, respectively. A key to the classification of world known species of Megabeleses Takeuchi is provided. This work has laid a foundation for the identification, monitoring and control of this pest.

Objective: This study aims to investigate the ecological safety of transgenic poplar 107(Populus×euramericana 'Neva'), and to provide scientific basis for further popularization and application. Method: In this study, the composition, structure, diversity and stability of arthropod community in grafted transgenic 107 poplar (Btcry1Ac and API gene) and control 107 poplar were investigated for five consecutive years. Result: A total of 54 091 arthropods belonging to 13 orders were collected, of which, Lepidoptera, Coleoptera, Coleoptera, Diptera, Hymenoptera and Araneae were the main groups. Lepidoptera is dominant in individual number. Compare with the control 107 poplar, the quanity of pest sub-communities in transgenic 107 poplar was significantly lower (P < 0.05). The number of target pests Clostera anachoreta and Hyphantria cunea decreased significantly (P < 0.05). But there was no significant difference (P>0.05) in species and individual number of natural enemies and neutral arthropod community. The natural enemies of Coccinellidae, Araneae and the other neutral insects of Monamorium pharaonis and flies showed increased to a certain degree year by year. There were significant interannual differences in species and individual numbers of transgenic 107 poplar sub-community (P < 0.05). The characteristic index of arthropod community in transgenic 107 poplar forest showed that the diversity and evenness index was higher than that in the control 107 poplar forest, and the dominance index was lower. There were significant interannual differences in the community characteristic index of transgenic 107 poplar forest (P < 0.05). Stability analysis showed that the ratio of total community species to total community individual (S_s/S_i), the ratio of herbivorous insects species to herbivorous insects individuals (S_p/S_b), and the ratio of predatory natural enemies individuals to herbivorous insects individuals (S_a/S_b) in transgenic 107 poplar forest were significantly higher than those in the control 107 poplar forest (P < 0.05), indicating that the transgenic 107 poplar had more species and fewer individuals, and the restriction on interspecific number was stronger than that of the control 107 poplar. But the S_n/S_a in transgenic 107 poplar forest and S_n/S_p were not significantly different from the control 107 populus (P>0.05), indicating that the number of predatory natural enemies species and individuals in the transgenic 107 poplar forest were not significantly different from those in the control 107 poplar forest (P>0.05), and the community structure of arthropod in the transgenic 107 poplar forest was relatively stable. Conclusion: Transgenic 107 poplar has a continuous insect resistance, and has no obvious adverse effects on natural enemies and neutral arthropod sub-communities. The transgenic 107 poplar has high ecological safety.

Objective: This study aimed to understand the community structure of raptors in Changdao County of Shandong Province, China, and reveal the population dynamics, autumn migration timing, migration route and stopover sites of Oriental Honey Buzzard Pernis ptilorhynchus, so as to provide a scientific basis for the conservation and management of this species. Method: In the autumn of 1987-2019, the regular banding activities were conducted in the fixed site of Daheishan islands, Changdao County of Shandong Province, and the long-term monitoring data of the number of raptors were collected. Two Oriental Honey Buzzards were tagged with GPS transmitters in October 2019, to collect the autumn migration information. SPSS 22.0 was used to analysis the community composition of raptors and the population trend of Oriental Honey Buzzard. ArcView GIS 3.3 and Google Earth were used to analysis the GPS tracking data. Result: A total of 78 039 individuals of 29 raptor species were banded during 1987-2019. The number of Accipitriformes, Strigiformes and Falconiformes in the community accounted for 60.74%, 38.59%, and 0.66%, respectively. The Oriental Scops Owl (Otus sunia), Besra (Accipiter virgatus) and Eurasian Sparrowhawk (Accipiter nisus) were dominant in the raptor community, accounting for 32.54%, 29.48% and 23.19%, respectively. The dominance index of Oriental Honey Buzzard in the community showed an upward trend in the past 33 years, with an average annual increase by 4.1%. The stopover at Changdao mainly happened from mid September to Mid October in autumn migration process, and the population peaked from 19^th September to 2^nd October. According to the GPS tracking, both the adult female and juvenile male migrated across China in the southwest after leaving from Changdao, and arrived at their wintering grounds in Malaysia and Vietnam on November 18^th and December 7^th, respectively. The average travel speed of the adult female was at (44.6 ±17.5) km·h^-1 and the maximum speed was at 88.7 km·h^-1, which were faster than those of the juvenile male, averaged at (40.4 ±18.4) km·h^-1 and maximized at 81.7 km·h^-1. Conclusion: The dominance of the Oriental Honey Buzzard in the community shows an increasing trend. Compared to juvenile male, the adult female makes less stopover, travels longer distance, migrates faster and arrives at wintering ground of lower altitude earlier. Thus the Oriental Honey Buzzard may adopt a differential migration strategies that would reduce interspecific competition at stopover sites and wintering grounds. It can be inferred that different geographical populations may adopt the chain migration strategy, i.e., further northern wintering population breed in northernmost region, indicating that its breeding habitats quality gradually change with altitude.

Objective: Detailed analysis of spatial dominance of individual tree species was carried out in order to provide a theoretical basis for the protection of key species and the maintenance of species diversity in forest communities. Method: In this study, based on the spatial dominance indices(tree size dominance and hyperbolic tangent indices), we constructed marked second-order characteristic functions to investigate the changes of spatial dominance of main tree species at different spatial scales. We simulated dependent, spatial marked point patterns to test the effectiveness of the constructed marked second-order functions and to analyze the influences of spatial aggregation of conspecifics on the spatial dominance of focused tree species. We investigated the changes of spatial dominance of the main tree species at different spatial scales in a 1.6 hm² forest plot in Yachang nature reserve and explored the relationships between tree dominance and species mingling. Result: 1) The studied forest community was an old-growth forest in which structural diversity was rich. A total of 86 species, 61 genera and 35 families were recorded, and the basal area of this stand was 49.81 m²·hm^-2. Different species in the community had different ranges of DBH distributions. Larger-sized tree species such as Rhododendron cavaleriei and Liquidambar formosana were the dominant tree species in the stand, and tree species of small-sized species, e.g. Ilex ficoidea and Eurya nitida, were also dominant in terms of their abundances. Size dominance and hyperbolic tangent index values of different tree species indicated that spatial dominance of tree species was associated with the population mean DBH. 2) All the tree species had a tendency to attract trees of similar sizes at small scales, and generally, spatial dominance of large-sized tree species was lower than the expected value or simulation envelopes constructed from the null model. However, spatial dominance for small-sized tree species was significantly greater than the expected, and its value tended to approach the expected value with the increasing spatial distance. 3) Spatial aggregation of conspecifics can increase or decrease the degree of species dominance. For large diameter tree species, such as L. formosana, conspecific aggregation resulted in the decrease of its spatial dominance; on the contrary, conspecific aggregation can increase species spatial dominance for small-sized tree species such as I. ficoidea. Conclusion: Our analysis of both simulated and experimental plot data showed that mark dominance second-order functions can effectively describe the spatial dominance of tree species at different scales. The species spatial segregation effects might reduce the competitive exclusion of inferior species by dominant species, and thus can maintain species coexistence and improve the species diversity in forest communities.

Objective: Based on the results of remote sensing quantitative estimation of vegetation coverage, the temporal and spatial characteristics of vegetation coverage and topographic differentiation effects were analyzed statistically, and the driving factors of vegetation coverage changes were also discussed, which were expected to provide a reference for ecological planning, ecological environmental protection and forest fire prevention in the study area. Method: In this study, Chongli core area of Beijing Winter Olympic Games was taken as the research area, GF-1 WFV and Sentinel-2 multispectral images were used as data sources, and the pixel dichotomy method of DNVI was used to estimate the vegetation coverage of the study area in 2014, 2016 and 2020. Combined with digital elevation model, the spatial and temporal variation characteristics of vegetation cover and its topographic differentiation were analyzed by difference index, Markov model, dynamic attitude of vegetation cover and topographic distribution index. Result: 1) The spatial difference of vegetation coverage in the study area is significant, showing a pattern of low vegetation coverage in the middle and high vegetation coverage in the periphery, which is closely related to the topography and geomorphology of the whole study area. The vegetation coverage in the mountainous area is high, while that in the plain area or the mountain base is the area of human activities, and the vegetation coverage is relatively low. 2) The vegetation status of the study area was mainly dominated by middle and high vegetation coverage. In 2014, 2016 and 2020, the areas covered by the three planting grades accounted for 81.59%, 90.00% and 86.88%, respectively. The vegetation coverage of the three periods in the study area was at a good level (more than 80%), indicating that the vegetation growth status in the study area was perfect. 3) For the elevation gradient, from 2014 to 2016, the improved type and the significantly degraded type had a distribution advantage below 1 800 m, but there was no distribution advantage above 1 800 m, and the slightly degraded type had a distribution advantage below 1 700 m and above 2 000 m. From 2016 to 2020, the improved type and degraded type under 1 700 m had a distribution advantage, and the obvious degraded type showed a strong distribution advantage. From 2014 to 2020, the significantly improved type had a distribution advantage below 1 700 m and had a weak distribution advantage above 2 000 m, while the significantly degraded type showed a strong dominance distribution below 1 700 m and had no distribution advantage above 1 700 m. 4) From 2014 to 2016, the improved type had a dominant distribution on sunny and semi-sunny slopes, while the slightly degraded type had a dominant distribution on shady and semi-shady slopes. 5) From 2014 to 2016, the improved vegetation had a dominant distribution on sunny slope and semi-sunny slope, and the significantly degraded vegetation had a dominant distribution on shady slope. From 2016 to 2020, the slightly improved vegetation had a dominant distribution on sunny slope and semi-sunny slope, and the significantly degraded and slightly degraded vegetation had a dominant distribution on shady slope. Conclusion: 1) The vegetation coverage was spatially low in the middle and high in the surrounding areas. The structure of vegetation coverage among different levels in 2014, 2016 and 2020 was stable, but the local vegetation coverage was seriously degraded. The overall trend is to increase vegetation coverage. 2) The vegetation coverage of the study area showed a regular distribution at different levels of altitude, slope and aspect; there are significant differences between the types of vegetation coverage changes and topographical factors. Obviously the degraded areas gathered where the slope is less than 8° and the altitude is 1 533-1 700 m, but do not show obvious differentiation in the slope direction, mainly due to the construction land for the Winter Olympics venues. Obviously improved vegetation coverage is concentrated in sunny and semi-sunny slope areas, indicating that the effects of artificial afforestation are more obvious. 3) The focus of forest fire prevention is in the mountainous areas with a high vegetation coverage.

Objective: The random-volume-over-ground(RVoG) model has been widely used to estimate forest height through polarimetric and interferometric synthetic aperture radar(PolInSAR) technology, and the three-stage inversion algorithm is a geometrical method to solve the RVoG model to estimate forest canopy height. However, the conventional three-stage algorithm, solving the ground phase and the volume coherence based on the polarization scattering features of L and P bands, could not accurately estimate the ground phase and the volume coherence with TanDEM-X data of X-band. In practical application, the establishment conditions of the model were difficult to strictly meet, and due to the influences of terrain, the accuracy of tree overestimation was not high. In order to improve the estimation accuracy, an improved method of forest height retrieval based on RVoG model and TanDEM-X SAR data was proposed in this paper. Method: The research object was Pinus kesiya var. langbianensis pure forest and P. kesiya var. langbianensis mixed forest in Simao district of Pu'er city. The experimental method included: (1) the classical three-stage inversion algorithm, (2) the improved three-stage inversion algorithm with the ground phase optimization, (3) the improved three-stage inversion algorithm with the volume coherence optimization and (4) the improved three-stage inversion algorithm with underestimation compensation. Result: The results showed that: the forest height of method (1) based on RVoG model was underestimated (r=0.11, bias=-26.20 m and RMSE=7.16 m); the estimation accuracy of method (2), (3) and (4) was better than that of method (1), in which method (4) was the best(r=0.79, bias=-1.69 m and RMSE=2.56 m); the estimation effect of P. kesiya var. langbianensis pure forest (r=0.81, bias=1.40 m and RMSE=2.27 m) was better than that of P. kesiya var. langbianensis mixed forest (r=0.72, bias=-3.09 m and RMSE=2.87 m). Conclusion: Compared with the classical three-stage inversion algorithm, the improved three-stage inversion algorithm based on TanDEM-X SAR data might have a better accuracy in this paper.

Objective: Interspecific hybridization of Camellia oleifera is an important way of germplasm innovation. This study aims to clarify the law of genetic variation of parental and offspring chromosome, which could help guide the selection of descendant materials and the configuration of backcross combination, and provide reference for the subsequent cross breeding research. Method: The root tips of cuttings of parents and 18 excellent F1 plants were selected as materials, the chromosome karyotype characteristics of parents and hybrids were studied by means of an improved chromosome preparation technique and karyotype analysis software, and the chromosomal inheritance and variation of parents and hybrids were analyzed by karyotype near coefficient clustering. Results: 1) The karyotype of male parent 'Huashuo' and female parent 'Youza 2' was 2B type, with m-type chromosome in the majority and sm-type chromosome in the minority. The karyotype formula of female parent 'Youza 2' was 2n = 91 = 53m (4SAT) + 38sm (2SAT). The variation range of chromosome relative length was 1.26% ~ 2.97%, the proportion of chromosomes with arm ratio greater than 2 was 17.8%, the chromosome length ratio was 2.36, and the karyotype asymmetry coefficient was 62.36%. The karyotype formula of male parent 'Huashuo' was 2n = 90 = 62m (2SAT) + 28sm (4SAT), the relative length of chromosomes ranged from 1.50% to 3.00%, the proportion of chromosomes with arm ratio greater than 2 was 4.4%, the ratio of chromosome length was 2.00, and the asymmetry coefficient of karyotype was 59.38%. 2) Most of the karyotype parameters of hybrid progenies were between male and female parents, most of chromosomes were m-type and sm-type, a few of chromosomes were st-type. The number of sm-type chromosomes was greater than that of m-type ones in some hybrid progenies (YH-14 and YH-18). The variation range of chromosome length was large, with generally in 1.05%~3.32%, most of which were M1 and M2 chromosomes. The variation range of the karyotype asymmetry coefficient was 61.01%~63.38%, and the karyotype was 2A or 2B type. 3) The results of karyotype cluster analysis showed that when the similarity coefficient of karyotype was 0.9660 and the distance coefficient was 0.0340, the hybrid progenies could be divided into two groups: most of them were clustered with the female parent 'Youza 2', only YH-11 and YH -15 were clustered with male parent 'Huashuo' into the other group. Conclusion: The karyotype parameters of most of the hybrid progenies are between the male and female parents, and the karyotype parameters of a few hybrid progenies vary greatly. In addition, the karyotypes of most individual plants in the hybrid progeny population are more similar to that of the female parent 'Youza 2', and only a few are more similar to that of the male parent 'Huashuo'. The results can provide a theoretical basis for the cross breeding of Camellia oleifera and the creation of new Camellia oleifera germplasm.