[Objective]The release of nitrogen and phosphorus from litters at different phenological stages can be directly supplied to plants to meet the demands for nutrients to a certain extent. Soil fauna can promote nutrients release from foliar litter, and also compete with plants for available soil nutrients and other resources, but the hydro-thermal conditions and litter quality at different phenological stages could have direct impacts on play activities of soil fauna and other decomposers. Therefore, understanding of the effects of soil fauna on nitrogen and phosphorus release from litters is one of the essential components in knowing the ecological linkages between litter decomposition and plant growth.[Method]Litters of four representative tree species including Pinus massoniana and Cryptomeria fortunei as plantation species and Cinnamomum camphora and Quercus acutissima as secondary forest species in subtropical evergreen broad-leaved forests in Sichuan Basin of southwestern China were selected for the study. Litterbags with different mesh sizes (0.04 and 3 mm) were used to exclude soil fauna. To simulate the natural decomposition in field from November 2011 to October 2012, litterbags were sampled at different stages of leaf development: defoliation, budding, expanding, maturing, peaking and declining, in order to analyze nitrogen and phosphorus contents, release rate and characteristics of the release during the litter decomposition process with and without soil fauna.[Result]Nitrogen content tended to increase with the progress of litter decomposition regardless of tree species. Soil fauna increased nitrogen content for P. massoniana and C. camphora during the leaf maturing stage, but decreased nitrogen content for C. fortunei and Q. acutissima. Litter phosphorus content peaked during leaf maturing and peaking stages. Soil fauna had a significant impact on litter phosphorus content for C. camphora at the leaf maturing stage, but not significant for the other three species. Moreover, soil fauna significantly affected the processes of nitrogen and phosphorus release during litter decomposition. When excluding soil fauna, litter nitrogen was released at the leaf expanding stage and followed by continual decrease for all the 4 species, but litter phosphorus exhibited release at leaf expanding and maturing stages, accumulation at the peaking stage and release again at the declining stage. However, with soil fauna exists, the litter nitrogen and phosphorus for P. massoniana and C. camphora showed obvious accumulation at the maturing stage but release at the peaking stage, while those for C. fortunei and Q. acutissima showed release at the leaf maturing stage but accumulation at the peaking stage. After one year decomposition of litters, soil fauna significantly promoted litter nitrogen release for C. fortunei and Q. acutissima and litter phosphorus release of P. massoniana, but limited litter nitrogen release for P. massoniana and C. camphora and litter phosphorus release for C. camphora, C. fortunei and Q. acutissima. Soil fauna limited litter nitrogen and phosphorus release for P. massoniana and C. camphora at the defoliation and budding stages compared with other stages. In contrast, soil fauna promoted litter nitrogen and phosphorus release for P. massoniana, C. camphora and C. fortunei at leaf expanding, maturing and peaking stages.[Conclusion]Soil fauna significantly influenced the nitrogen and phosphorus release during litter decomposition in the subtropical evergreen broad-leaved forests in Sichuan Basin. The impacts on litter nitrogen and phosphorus release were relatively small at defoliation, budding and expanding stages in which plants grow slowly, but more evident at the leaf maturing and peaking stages in which plants consume a lot of nutrients, to some extent indicating that the competitive relationships between flora and the soil fauna.

[Objective]The study of interspecific associations of dominant plant populations respectively in the layers of tree, shrub and herb in communities of secondary natural forest of Pinus armandii in Qinling Mountains is to reveal the inherent links of interactions among different populations during the process of community development, to clarify the natural rules of community development in relation to the succession and interspecific association, and to provide the theoretical basis for sustainable management of forest communities of P. armandii in Qinling Mountains.[Method]Typical communities of secondary natural forest of P. armandii in Huoditang Forest Farm in Qinling Mountains were selected for the studies. 2×2 contingency tables of species presence/absence data were used as the basis for the analyses of overall interspecific associations among dominant plant populations in different layers of tree, shrub and herb using the variance ratio method. χ² test and Jaccard index were used to characterize interspecific associations of 15 tree species, 19 shrub species and 15 herb species.[Result]In the community of secondary natural forest of P. armandii, the overall interspecific associations among dominant plant populations respectively in tree, shrub and herb layers displayed non-significant positive, non-significant negative and significant positive correlations. The χ² test showed positive correlations of majority of species-pairs in all layers of tree, shrub and herb, accounting for 81.9%, 77.2%, and 81.9%, respectively; followed by negative correlations of species-pairs accounting for 15.2%, 13.5%,and 1.8% respectively. Only few species-pairs displayed no correlations. The numbers of species-pairs with extremely significant or significant positive correlations in the 3 different layers were 11, 2, and 5, respectively, while those of extremely significant or significant negative correlation were 13, 2, and 1 respectively. The JI values were highly consistent with the results of χ² test, indicating that the species-pairs in 3 different layers with higher JI values had extremely significant or significant positive correlations. Among those species-pairs, the JI values of Acer davidii and Carpinus cordata, A. davidii and Quercus spinosa, Q. spinosa and Tilia paucicostata, Desmodium elegans and Lonicera hispida, Fragaria vesca and Artemisia dubia were greater than 0.6, indicating interdependency between each of the species-pairs. The JI values of the rest were smaller. [Conclusion]The interspecific association of species-pairs in tree, shrub and herb layers in community of secondary forest of P. armandii in Qinling Mountains was obvious. The overall community structure was mixed forest with certain independence among main plant species and tending to form a relatively stable community as a whole. In the tree layer, the interspecific association was relatively weak with certain independence, to a low extent though. The structure at tree layer tended to be stable. In the shrub layer, however, the dominant population was at an unstable stage with dynamic succession. The population structure of herb layer was stable. To conclude, the analyses of interspecific association can be used as an effective way to detect the stability of forest communities and the dynamic changes of interspecific relations during the process of succession. In practice, tree species with higher positive correlations should be protected as ecological species for shortening the succession process of communities of secondary natural forest of P. armandii in Qinling Mountains.

[Objective]Aims We measured the composition of foliar carbon and nitrogen stable isotopes (δ¹³C,δ¹⁵N) in Cunninghamia lanceolata plantations at ages of 3, 8, 14, 21 and 46. The aim of this study is to use the isotopic compositions as indicators to explore the degree of nitrogen saturation of C. lanceolata in various forest and foliar ages. [Method]Our experimental site is located at Xiayang forest farm, in Nanping, Fujian, China, where five adjacent C. lanceolata stand at various ages were selected. Four 20 m×20 m plots were established in each stand, the leaves (at different foliar ages) and soil from each plot were collected. The δ¹³C and δ¹⁵N of leaves and soil were measured by using Thermo Scientific MAT253, and the foliar N concentrations were measured with Elemental Analyzer Vario ELIII, and the ¹⁵N enrichment factors (EF) were calculated by foliar δ¹⁵N minus soil δ¹⁵N. [Result]The result showed that foliar δ¹⁵N ranged from -2.52‰ to 2.81‰, and the foliar N concentrations ranged from 7.72% to13.5%. There were significant differences in these two parameters among stand ages were, and they all tended to be higher in the 3- and 46-year-old stand compared with those in 8-, 14- and 21-years-old stand. However, no significant difference in foliar δ¹⁵N was found among different foliar ages. We also found a significant and positive correlation between foliar δ¹⁵N and nitrogen concentration. Meanwhile, the ¹⁵N enrichment factors (EF) in leaves were significantly different among foliar ages, and the young and old stand tended to be closer to zero. The foliar δ¹³C ranged from -29.93‰ to -27.88‰ and there was no significant difference in the δ¹³C among stand ages. However, there was significant difference in foliar δ¹³C among foliar ages and it tended to decline with foliar age. [Conclusion]We could attribute the different δ¹³C among stand and foliar ages to the water use efficiency and the photosynthetic efficiency. The difference of foliar δ¹⁵N, foliar N concentrations and ¹⁵N enrichment factors in various forest ages indicate that nitrogen might still be a factor that limits the growth of C. lanceolata at pole stage in subtropical region of China, and further studies are needed to verify it, for example, taking the influence of mycorhiza into consideration.

[Objective]This research was carried out to investigate the short-term responses and regular patterns of leaf gas exchange characteristics of Cotinus coggygria seedlings, collected from different locations, to soil water stress.[Method]A field experiment was set and the one-year-old C. coggygria seedlings were collected from three locations: Xishan Mountains in Beijing, Taishan Mountains in Shandong Province and Jiangxian County in Shanxi Province. The seedlings were subjected to three water regimes, including control (CK, 75%-80% of field water capacity), moderate stress (MS, 55%-65% of field water capacity) and severe stress (SS, 35%-45% of field water capacity). A LI-6400 portable photosynthesis measurement system was used to determine the light response curves (P_n-PAR) and CO₂ response curves (P_n-C_i) of the mature leaves, and the statistical analysis software SPSS 20.0 was applied to fit the curves. Each photosynthetic parameter was calculated according to Levenberg-Marquardt iterative principle of nonlinear least square method.[Result]1) The CO₂ assimilation ability of C. coggygria seedlings decreased significantly (P < 0.05) as drought stress degree increased and drought stress time prolonged. The decrease was mainly ascribed to block of CO₂ diffusion and photosynthetic electron transport and decline of light energy utilization efficiency when water deficit occurred. The stomatal conductance to CO₂ + mesophyll diffusion conductance to CO₂(g_sc+ g_m), apparent quantum yield (AQY), light saturation point-light compensation point (LSP-LCP), maximum electron transport rate (J_max) and maximum electron transport rate / maximum carboxylation rate (J_max / V_c,max) of C. coggygria seedlings treated with severe stress were lower than those in control by 50.5%, 12.0%, 21.0%, 37.9% and 16.9%, respectively. The g_sc, g_m, AQY, LSP-LCfP and J_max / V_c,max of C. coggygria seedlings during late stage of drought stress were lower than those during mid-stage of drought stress by 18.7%, 81.0%, 19.3%, 4.6% and 5.5%, respectively. 2) Water deficit promoted the low light use efficiency and carboxylation rate of C. coggygria seedlings to a certain extent. 3) The limitation on photosynthesis due to stomatal conductance to CO₂ (l_s) and due to mesophyll diffusion conductance (l_m) treated with moderate and severe drought stress were higher than that in control by 36.9% and 25.3%, 9.7% and 103.0%, respectively. Thus, stomatal limitation and mesophyll diffusion limitation were the main reasons for net photosynthetic rate decline under moderate drought stress and severe drought stress environment, respectively. Additionally, the average drought-treated l_s and l_m treated were higher than those in control by 17.7% and 46.0%, and those during late stage of drought stress were higher than those during mid-stage of drought stress by 47.0% and 71.1%, respectively. 4) Compared with those seedlings before drought stress treatment, the light-saturated maximum net photosynthetic rate (P_n,max), CO₂-saturated maximum photosynthetic capacity (A_max), maximum net photosynthetic rate limited by Rubisco activity and amount (A_c,max), maximum net photosynthetic rate limited by RuBP regeneration (A_j,max), V_c,max, triose phosphates utilization rate (V_TPU) of seedlings under SS treatment were all declined, and those declines of seedlings from Shanxi were greater than those of seedlings from Beijing and Shandong by 38.0% and 50.3%, 40.7% and 46.3%, 45.7% and 51.2%, 52.4% and 54.2%, 47.3% and 55.8%, 55.5% and 82.6%, respectively. However, the LCP and dark respiration rate (R_d) of seedlings from Shanxi Province under continuous drought stress were lower than seedlings from Beijing and Shandong Province by 31.2% and 47.5%, 27.2% and 9.2%, respectively. [Conclusion]There were significant differences in the sensitivity to continuous drought stress among the C. coggygria seedlings from the three locations of Xishan Mountains in Beijing, Taishan Mountains in Shandong Province and Jiangxian County in Shanxi Province. The leaf carbon assimilation ability of seedlings from Shandong under severe drought stress was remarkably stronger than that from Beijing and Shanxi, and the ability of seedlings from Beijing was significantly stronger than seedlings from Shanxi. The diffusive resistance to CO₂ and photosynthetic electron transport resistance of seedlings from Shanxi were significantly greater than seedlings from the other two locations, while the LCP and R_d were the smaller than the other two locations. Consequently, the photosynthetic characteristic parameters of C. coggygria seedlings from Jiangxian County in Shanxi changed more violently than those from Xishan Mountains in Beijing and Taishan Mountains in Shandong in response to arid environment, however, the seedlings from Shanxi were more capable of lowering the light compensation point and the level of dark respiration metabolism to ensure accumulation of photosynthetic assimilation products than those from the other two locations.

[Objective]Bursaphelenchus xylophilus(nematode), the causative agent of pine wilt disease, has devastated pine forests for a long time. A safe and efficient technique is needed urgently to control the nematode and prevent the pine wilt disease. The previous studies indicated that the matrine is not suitable for preventing the pine wilt disease although it is an environmentally friendly biocontrol agent. To develop low toxicity and effecient nematicides, the gene, function and protein inhibition of acetylcholinesterase 1 in pine wood nematode B.xylophilus, was studied.[Method]The B.xylophilus populations used in this study were collected from Guangdong Province in 2007. The host is masson pine (Pinus massoniana).The nematodes were separated by the Behrman funnel method, cultured at 25 ℃ without light and fed on Botrytis cinerea moss. The gene, function and protein inhibition of acetylcholinesterase 1, was studied. The full-length of BxACE 1 gene was cloned and the sequence was analysed. The BxACE 1 gene function was silenced by the method of RNAi and inhibited by proteins inhibitor to study the insecticidal effect of matrine.In the meantime, Q-PCR was used to identify RNAi effects. [Result]A total of 2 145 bp full-length gene was obtained by splicing 5' and 3' sequence, named BxACE 1. Homologous sequences of multiple sequence alignment showed that the nematode ACE evolution speed was consistent with nematodes. Protein 3D structure analysis showed that BxACE 1 was 13 β-fold surrounded by 14 α-helix. In view of the fact that the more hydrogen bonds in combination with the more stable, the huperzine A was selected as a more efficient inhibitor of acetylcholinesterase 1 protein by docking technique. Huperzine A itself had low toxicity to nematodes and the common aplication of RNAi and huperzine A had still low toxicity to nematodes, but the nematodes survivals in 24 h, 48 h and 72 h after RNAi treatment and inhibitor (treated nematodes with 0.03% matrine + 1 μmol ·L^-1 Huperzine) treatment were not significantly different with each other indicating that Huperzine A and RNAi BxACE 1 genes had similar treatment effects to nematodes.[Conclusion and other]The results indicated that the nematicidal activity of matrine was improved after the BxACE 1 was silenced by the method of RNAi or the BxACE1 was inhibited. RNAi technology easily proved that blocking BxACE 1 gene function could improve the nematicidal effect of matrine, while dsRNA could degrade easily, which limited the extensive application of the technique in production practice. Huperzine A, screened with docking technique,was able to combine with BxACE1 stabily. Appraisal of inhibitory effects of inhibitors showed that huperzine A improved the nematicidal effect of matrine, which had the development potential as bio-control auxiliary agents, could be used as an alternative of gene silencing technology that inhibited acetylcholinesterase 1 gene of nematodes. Therefore, this study further put forward that huperzine A, the acetylcholinesterase inhibitor, used to block BxACE 1 gene function could improve the effects of botanical nematicidal like matrine and so on. Through inhibition of ACE, ACEIs made the acetylcholine accumulate in the synaptic clearance, and hence made the effect time of acetylcholine longer. ACEIs caused the choline levels to increase acutely in a short period of time by inhibiting nematodes acetylcholinesterase activity, which resulted in the poisoning death of nematodes. The representative pesticides class are organophosphorus compounds and carbamate compounds, most of which were non-reversible ACEIs. Huperzine A is a half terpene alkaloid derived from Huperziaceae plants, Huperzia serrata, and is a kind of high efficient, high selective, and reversible ACEIs. In this study, huperzine A was introduced to B.xylophilus, which was a new attempt to apply the botanical source medicament.

[Objective]Taxus chinensis var. mairei is an endemic, endangered and first-class protected tree species in China. This species is considered as an important botanical resource of taxol which is an effective medicinal compound against various cancers. Phosphate solubilizing bacteria (PSB) Sinorhizobium meliloti CHW10B,which was isolated from rhizosphere of T. chinensis var. mairei, showed significant growth-promoting effect for T. chinensis var. mairei. Survival in the environment and efficient colonization are a necessary and vital step for plant-beneficial bacteria to playing a role in plants. In order to effectively take advantage of S. meliloti CHW10B, the colonization of this strain in rhizosphere and roots of the seedlings of T. chinensis var. mairei was studied via the green fluorescent protein (GFP) gene label technique. [Method]The green fluorescent protein (GFP) technique is widely used to study the colonization of target bacteria in rhizosphere and host plants. The shuttle vector pGFP4412, containing one copy of the constitutively expressed GFP, neomycin and ampicillin resistance genes in tandem, was transformed into CHW10B strain by using the repeated freezing and thawing methods with modification. Then the transformants with strong fluorescence expression and stable hereditary were further screened using fluorescence microscopy. The morphological characteristics of the cell and colony for CHW10B and CHW10B -GFP were identified and the phosphate-dissolving abilities of the two bacterial strains were determined with the molybdenum-antimony anti-spectrophotometric method. After inoculation by pouring the bacteria to root surface of T. chinensis var. mairei, the survival and colonization of strain CHW10B labelled with GFP were investigated by combining antibiotics plate recovery with fluorescence microscopy. [Result]The transformants (CHW10B-GFP2) were successfully obtained, and the stain had strong fluorescence expression and stable hereditary. The cells of CHW10B-GFP2 and CHW10B were both Gram-positive, short rod-shaped. The colonies of the two strains were all circular, entire margin and a sticky. But the colors of colonies were not same, strain CHW10B was milky white, and CHW10B-GFP was light brown. Phosphate-dissolving abilities of CHW10B-GFP2 and CHW10B were similar and the content of soluble P in the supernatant was 639.12 mg·L^-1 and 656.57 mg·L^-1 in 4 days after inoculation. The colonization amount of the strain CHW10B-GFP in the rhizosphere soil of T. chinensis var. mairei had big variations throughout the experiment after inoculation. At the first day after inoculation, the number of the labelled cells reached 6.08×10⁷cfu·g^-1 in the rhizosphere soil. Thereafter the bacterial population decreased sharply and then began to increase in 15 days after inoculation. In 25~40 days after inoculation, the bacterial population subsequently increased and leveled off. In 40 days after inoculation, many cells of this strain could be observed in the surface and inside of seedling roots by a Fluorescent microscope. [Conclusion]This study demonstrated that the marked strain could survive stably in the rhizosphere of T. chinensis var. mairei. Moreover, CHW10B-GFP could colonize in the root surface and internal of the seedlings, indicting strain CHW10B was an endophte. The study would provide a scientific basis for the exploitation and utilization of strain CHW10B.

[Objective]Laccase has been widely used in many industrial fields, such as textile, printing, environment bioremediation and bioelectronics. Microbial laccases, especially from deuteromycetes have become the main laccase resource for theoretical and practical researches due to the short fermentation cycle, mild reaction condition and genetica reconstruction advantage. In this research, soil samples were collected in the primary forest in Liangshui Nature reserve, China in order to isolate laccase-producing fungi and improve the culture conditions. This research focused on the resource exploration of laccase-producing fungi and enhancement of laccase production so as to supply fungal strain and fermentation parameters for enlarging industrial practice of laccase production. [Method]Lignin-sodium sulfoacid was used as the sole carbon source for the enrichment culture,and guaiacol-PDA selective plates were used to isolate laccase-producing fungi. Two distinctive agents, ABTS and SGZ (4-hy-droxy-3,5- dimethoxybenzaldehyde azine) were both used for primary screening and then shaking fermentation was adopted for secondary screening of laccase-producing fungi. A fungus strain which had a short period of fermentation cycle and high laccase production was obtained and identified as a deuteromycete fungus, Myrothecium verrucaria NF-08 according to morphological characteristics and sequence analysis of rDNA-ITS. The laccase activity was determined by ABTS and the extra-cellular protein was assayed according to Lowry method. Based on the dynamic investigation of laccase activity, fungus growth and protein content, single factor experiments were conducted to investigate effects of the following factors on laccase production, including the categories and concentrations of carbon and nitrogen sources, initial pH value of the medium, inoculum and liquid volume in the flask as well as the induction of laccase substrates. [Result]The strain NF-08 was isolated, purified and identified as a deuteromycete, Myrothecium verrucaria The laccase production of M.verrucaria NF-08 showed synchronism in concordance with both hypha growth and extracellular protein amount. The laccase activity reached the peak value of 9.28 U ·mL^-1 on the 6^th day during the fermentation. The optimum carbon and nitrogen source were 4.0% glucose and 3.5% peptone, respectively. The best initial pH value of the fermentation medium was 7.0. The optimum culture conditions were liquid volume 60 mL in a 250 mL flask, inoculum 4%, temperature 30 ℃ and rotation 140 r ·min^-1. Gallic acid, ferulic acid and tannin significantly increased the laccase activity produced by M.verrucaria NF-08, especially for gallic acid. As a result of the optimization of medium components, culture conditions as well as substrate induction, the laccase activity reached 16.82 U ·mL^-1 which was 81.25% higher than that of the original strain. [Conclusion]A method for isolating, purifying and screening laccase-producing fungi from environmental samples was established. A laccase-producing deuteromycete fungus with short fermentation cycle and relative high initial laccase activity was obtained. The culture conditions were remarkably improved and laccase activity produced by M.verrucaria NF-08 was significantly increased. M.verrucaria NF-08 was a new microbial resource for laccase production and had great potential in enlargement fermentation in industrial practice. Furthermore, several meaningful works involved with M.verrucaria NF-08 would be carried on such as enzyme production and characterization, expression and regulation of the laccase gene. This would be beneficial to gain a better understanding of the deuteromycete laccase about the physiological role and ecological function. At the same time, the application fields of the deuteromycete laccase would be widen in the near future.

[Objective]Forest fires cause heavy loss to forest resources and society and economy and directly imperil the sustainable development of forestry and national ecological security. Study on the temporal and spatial distribution of forest fires and their risk analyses were helpful to understand the law of forest fires, to provide a scientific basis for forecasting, preventing forest fires and establishing different fiscal subsidy and insurance policies. The study is important to promote forest sustainable development and to maintain the national ecological safety. [Method]In order to find out the basic situation of forest fires in China, the forest fire temporal and spatial distribution characteristics and risk analysis were studied based on the yearbook data from 1950 to 2010 and by means of principal component analysis, cluster analysis and information diffusion theory. The temporal and spatial characteristics of forest fires in each province were comprehensively analyzed conducted, and further evaluated and classified by innovatively combining the disaster index. The fire risk level was quantitatively analyzed to provide scientific basis for forest fire prediction and prevention, to establish the fiscal subsidy policy, and to provide the basic support to forest safety risk prevention and risk decision. [Result]1) nnual average fire number was 12 683 times and burned an area of 674 800 hm² per year from 1950 to 2010, and the annual average fire number and the burned area showed a downward trend. Average annual fire-caused disastrous area was 79 500 hm² and showed an increase trend overall from 1988 to 2010; Annual average stand volume loss was 1.675 million m³ from 1988 to 2010 without obvious year-to-year variations; Annual average casualties was 214 people from 1988 to 2010 and showed overall a downward trend. 2) Human-caused fires accounted for more than 80% of the identified fires. Burning grass on waster land and burning charcoal were one of the main productive causes (38.47%), and sacrificial fires at graves were the main non-productive (19.92%). 3) Fire number in Eastern China and Southwestern China was significantly more than the other regions in China, while the burned area was significantly larger in Northeastern China than that in the other regions in China. 4) According to parameters of the general and large fire number, the major and catastrophic fire number, the burned area, the disastrous area, the stand volume loss, the young stand loss, and the casualties, this paper evaluated the fire situation in 31 provinces (The data of Hongkong, Macau and Taiwan are not included)using PCA and ranked them. Then the cluster analysis was conducted with comprehensive scores obtained by PCA. The 31 provinces were divided into 5 types: serious, heavy, moderate, general and light, and Hunan was most serious and followed by Heilongjiang, Guizhou and Yunnan. 5) With the information diffusion theory, the occurrence probability of general and large fire number in 3 000-9 000 was (> 0.482 4), the major and catastrophic fire number in 0-30 was (> 0.430 2) and the disastrous area under 150 000 hm² was (>0.407 2). [Conclusion]Frequent forest fires, large area in China were closely linked with climate change. The main reason causing the forest fire was man-made fire, and we must strictly control and manage field fire sources, and regulated productive and life fire-used behavior. Forest fires were with obvious regional feature and fire risk pressure was high in China. According to the results, it is suggested that it is important to strengthen the propaganda and education, take scientific measures for preventing, predicting and monitoring forest fires, establish reasonable fiscal subsidies and forest fire insurance policy, and maintain the forest health and national ecological security based on the accurate grasp of the national forest fires distribution and risk.

[Objective]To decrease the wood drying time, the microstructure characteristics of wood was changed. The moisture permeability and flowability were improved and new paths for moisture movement were established. The relationship of the process conditions of rolling-press pretreatment, the variation of the characteristics of cell walls and the drying rate, was constructed. [Method]The present work was based on the theories of viscoelasticity and moisture movement of wood. The lumber was compressed and horizontally passed through the intervals of two vertical arrangement rollers. The diameter of the rollers was 500 mm. The rotation speed of the rollers was 30 rmin^-1. Quarter-sawn and flat-sawn oak boards of 900 mm in length, 100 mm in width and 30 mm in thickness with moisture contents of 47%-55% were compressed by rollers in both radial and tangential directions, with three compression rates of 10%, 20% and 30%, and three compression times of 1, 4 and 9, respectively. The variation characteristics of the vessel element cell wall microstructure of the rolling-compressed samples and the drying rate of samples during conventional drying were studied. [Result]FE-SEM observations showed that the pit membrane of vessel elements broke and the wall of vessel elements cracked because of the pressure from rollers, which formed new paths for moisture moving. The drying period was shortened due to improvement of moisture permeability and flowability when increasing the amount and the broken degree of pit membrane, and the scale and size of cracked cell wall, with the increasing of compression rate and compression times. The results indicated that the drying rate of the treated samples was higher than that of the untreated samples in six drying stages and overall the drying process. The drying rate was increased with increasing the compression times when the compression rate and direction were the same. It was also increased with increasing the compression rate when the compression times and direction were the same. The drying rate of the quarter-sawn samples compressed in the radial direction was higher than that of the flat-sawn samples compressed in the tangential direction.[Conclusion]The drying cycles of treated samples were less than that of untreated samples when the initial and final moisture contents of the samples were 50% and 15%, respectively. The rate of shortened time of the lumber compressed by tangential direction was ranged from 6.67% to 23.64%, while that of compressed by radial direction was ranged from 4.55% to 13.02%. The results showed that the drying period of wood decreased because of the improving of moisture permeability and flowability, which were contributed by the rolling-press pretreatment.

[Objective]Producing wood-based rubber JN-type shock absorber is suitable for machinery equipment or automotive shock absorber, by use micron wood fiber in place of rubber and plastics. Theoretical feasibility of wood-based rubber JN-type shock absorber material selection, availability of manufacturing process method and the mechanical properties of micron wood fiber absorber sample are studying. The specific content of study include: wood-based rubber JN-type shock absorber mathematical modeling equations and simulation analysis and preparation of mold. [Method]Using cold vulcanized and composite materials fabric theory, pressing mold shaping method produces high elastic micron wood fiber JN-type damper. Pine micron wood fiber with a density of 0.439 g ·cm^-3, a moisture content of 12% to 15%, with an average thickness of up to 52 μm was chosen to make micron wood fiber JN-type damper sample, through the process of preparation, selection, mixed plastic, molded, heat packing, unloading mode and verification. The quality and volume of sample was measured, the shape state of sample was observed after immersion in water for 24 h. Micron wood fiber wood-based rubber JN-type shock absorber mathematical model based on the assumption, that its shape is ideal shape. Its upper seen as a standard trapezoidal station, the hole in the middle as standard cylinder; the base is a combination of rectangular, semi-circular and ramp round hole in the middle. Assuming coordinates system of NC machining and micron wood fiber JN-type damper mathematical model is parallel and in the same direction. Micron wood fiber JN-type damper based center was selected for the origin of coordinates, and makes mathematical model with the envelope and geometry modeling method, and carried out simulation by using Matlab. The driver of JN-type shock absorber various types and sizes was stored inside CNC machine, its mold processing is done by positioning setup process once. [Result]Using oil sludge product mold, micron wood fiber JN-type damper sample was produced, though a series of processing and production process. Sample density at 0.91-1.36 g ·cm^-3, the quality at 1.4-2.0 kg, it's not deformed when soaked in water for 24 h. Matlab simulation results prove micron wood fiber JN-type wood-based rubber shock absorber mathematical model has some versatility and accuracy. [Conclusion]Micron wood fiber cell wall are elastic, the cell structure of wood are destroyed, eliminating strength influence of cavity glue and knots. The wood fibers have mutually attractive force, after the molding process, to form a high compression ratio and highly elastic material likes rubber. With sample regulations preparing process, JN-type shock absorber was pressed by micron wood fiber is water resistant and meets the requirement of density and elasticity. Wood-based rubber JN-type shock absorbers' modeling is consisted of a base station and rule trapezoidal configured, model parameters has the practicality, versatility and accuracy. The molding process is completed in a mold to ensure the practical size and appearance of wood-based rubber JN-type shock absorber.

[Objective]The productivity of poplar plantation with successive rotations depleted seriously. Based on morphological and anatomical properties of the fine roots, the inter-rotation difference of fine root growth and its relation to the depletion of plantation productivity were studied to reveal mechanisms of the productivity depletion of plantation with successive rotations. [Method]Sample plots were set up in plantations respectively at the first and second rotations. Using the improved complete-root sampling method, fine roots (< 2 mm) of sample trees were collected and grouped into 1-5 classes according to orders of the roots. WINRHIZO root system analyzer (Canada) and corresponding software were used to determine the morphological properties: length and diameter. Furthermore, permanent paraffin sections of the 1-5 classes of fine roots were prepared to observe the anatomical properties: cross section diameter, cortex thickness and xylem diameter. Finally, several important parameters related to fine root morphology, i.e. specific root length (SRL), root tissue density (RTD), root length density (RLD) and percentage of xylem to cross section area were calculated. Least-significant difference (LSD) multiple comparisons were used to analyze differences of fine root morphological properties among the 1-5 root classes, and one-way ANOVA was used for the analysis of difference of the same class of fine root morphology between first and second rotations of poplar plantation (P<0.05). [Result]There were significant differences of biomass allocation among the fine root classes, and biomass allocation appeared to decrease with increase of root orders. The biomass of fine roots in the second rotation plantation was significantly higher than that in the first rotation, especially for 1,2 root classes (P <0.05). The mean root length was also significantly different among the root classes. The mean root length of 1,2 root classes was decreased and that of 3-5 root classes was increased in the second rotation plantation. Although root diameter showed no significant differences among root classes, it was still larger in the second rotation plantation. Also, the surface area, specific root length and root length density of 1,2 order roots were significantly higher than those of 3,4 order roots (P <0.05), but the specific root length showed no significant difference among orders in second rotation plantation. The surface area and root length density of 1,2 root classes displayed a significant increase in the second rotation, but specific root length was significantly decreased (P <0.05). The anatomical properties showed that the cross section diameter of all fine roots increased with root classes and the same trend was found with the area ratio of stele (or vascular cylinder) to cross section. The anatomical properties of the 1,2 root classes was characterized as primary structure in general, while phellem layer was formed from the 3^rd root class and cortex layer started to fall off.[Conclusion]There were significant differences in morphology ad functions among the 1-5 classes of fine roots. Fine roots of the 1,2 root classes were of primary structure, indicating that they serve as absorbing roots, while fine roots of the 3-5 root classes formed the secondary phellem layer, indicating that they act as transporting roots for water and nutrients. Successive rotations led to significant changes of fine root morphology and significant increases of fine roots biomass, indicating that the biomass allocation to underground part was increased in poplar plantation with successive rotations. This conclusion was consistent with the theory of optimal allocation of photosynthetic products under nutrient deficiency conditions. With fine roots mortality and turnover, the allocation pattern of fine root biomass of poplar plantation with successive rotations would have a negative effect on aboveground productivity.

[Objective]Larix gmelinii over cutting forest formed at the beginning of 1980s located at the chaocha forest farm, genhe forestry bureau, inner Mongolia, was selected as research object. The objective of this paper is to reveal the vertical structure characteristic of multi storied uneven-aged stand, and to provide some references for the further study on the succession trend and stand structure optimization.[Method]Based on the data of 10 sample plots in the larix gmelinii forest, the vertical stratification of stands of the over-cutting forest of Larix gmelinii was divided into main canopy layer, succession layer and regeneration layer, by using the principle of the canopies competition in height for light. The height, diameter distribution, species composition, forest stock volume and horizontal pattern of each layer were analyzed. [Result]1)The average height of the main canopy layer, succession layer and regeneration layer are 11.2 m, 6.8 m and 2.8 m, respectively. Through the variance analysis, the level was apparently difference at the level of 0.01. 2)With the increasing of vertical stratification of forest stands, the diameter distribution shifts from the reverse J-type distribution to the left-skewed unimodal-type distribution, and finally forms an irregular unimodal shape. The diameter distribution of main canopy layer was unimodal irregular, the peaks were found at 8~16 diameter. The highest peaks were found at 12 and 14 diameter. The succession layer level is left unimodal size distribution. The peak was mainly found at 8 diameter. The diameter class distribution of regeneration layer was reverse J type. The peak was found at 2 diameter. 3)The species composition in each layer varies apparently. The main canopy layer plays a vital role in the composition of the entire forest species, and the composition percentages of the two layers are closed to each other, which directly affects the composition of species in the regeneration layer. The species composition in the succession layer reveals three possibilities for the future forest stand succession trend: the Larix gmelinii percentage may increase; the white birch percentage may gradual increase; the species composition may be relatively stable. 4)With the increasing of forest layers, the forest stock volume increased. The average proportions of the main canopy layer, the succession layer and the regeneration layer in the total forest stock volume reached 67.3%, 28.6% and 4.1%, respectively. 5)The distribution pattern of each layer is of clustering type, which is not entirely consistent with the overall distribution pattern of stands. With the decline in the forest layer, the clustering coefficient increased gradually, and the degree of aggregation increased apparently. 6)Each layer has different effects on the forest structures and functions. With increasing the age of forest, trees in the regeneration layer will decrease. The regeneration layer will shift to the succession layer, and the diameter distribution in the succession layer will move to the right and gradually approach the diameter distribution in the main canopy layer. 7)The characteristics of different levels of the vertical structure of this study are based on the a (cut-off coefficient) value is 0.5. The results of each forest layer were quantitative analyzed. [Conclusion]We shall control the proportions and reasonable heights of trees for each diameter class of species and continuously ensure the existence of the regeneration layer, by starting with each layer of forest stand, optimizing the structure, regulating the succession of forest stand, and continuously managing the multiple-layer uneven-aged forest. Vertical structure is the characteristic of a particular stage of the forest. Along with the age growth, the vertical structure will be changed at different growth stages. How the expression of the vertical stand structure characteristics dynamically will be the focus of future research. In the stand, in-depth research is required for different species reach various forest layer heights and the time for the formation of the existing vertical hierarchy.

[Objective]Forest biomass is the main source of energy and nutrients of the forest ecosystem operation. Qilian Mountain forest reserve at the upper reaches of Heihe River Basin was selected as the research area. The forest inventory data, Landsat-5 TM images and ASTER GDEM products were used as data sources. The purpose of this paper is to explore the effect of terrain on the estimation of forest above-ground biomass (AGB) and select appropriate method for the inversion of forest AGB. [Method]First, a decision-tree classifier was constructed by taking into account of the special habitat of Picea crassifolia and the sensitivity of the green vegetation for ratio vegetation index, and the different responses of various objects on the texture features. The land-cover types of the research area was divided into two categories: forest (Picea crassifolia)—non-forest. The accuracy assessment of classification map was obtained by using field inventory data and high-resolution image of Google Earth (The overall accuracy of the classification is 90.39%, and the Kappa coefficient is 0.81). Then, the forest AGB was estimated using the multiple linear stepwise regression and k-NN. The k-NN was implemented by combining with RF algorithm. The change of the estimation accuracy before and after the topographic correction was analyzed. And the estimation accuracy of two different retrieval methods were compared with the forest survey data. Finally, the grade distribution of regional forest AGB was performed by the optimal estimation method. [Result]The estimation accuracy of multiple linear regression was R²=0.31, RMSE=34.41 thm^-2 before SCS + C topographic correction. But it was R²=0.46, RMSE=30.51 thm^-2 after SCS + C topographic correction. The optimal k-NN produced higher cross-validation accuracy (R²=0.54, RMSE=26.62 thm^-2) by using the data after SCS + C topographic correction than the outcome before SCS + C topographic correction. At the same time, it performed better than the effect of the multiple linear stepwise Regression. The regional forest AGB which was performed by the optimized k-NN (window sampling size was 7×7; distance measures was Mahalanobis Distance; k was 3) showed that the total of forest AGB of Picea crassifolia was 8.4×10⁷ t in this region, and the average was 96.20 thm^-2. [Conclusion]The appropriate terrain correction with SCS + C model could effectively eliminate the influence of the change of incident angle of the sun in complex terrain area. It could improve the estimation accuracy of the models. Compared with multiple linear stepwise regression, the optimal k-NN could avoid the phenomenon of learning and the problem of sample imbalances in the case of limited samples.

[Objective]In order to provide a theory basis for the use of leaf volatiles of Pistacia chinensis, it is necessary to understand its diel fluctuation and seasonal dynamics of volatile organic compounds and analyze its volatile composition and relative content.[Method]Five P. chinensis individuals were randomly selected from an adult P. chinensis plantation in North Campus, Shandong Agricultural University. The healthy compound leaves were collected from the outside canopy receiving uniform sunlight at 9:00, 12:00, 15:00, 18:00 and 21:00 on a sunny day in the spring of 2008 (may), summer (July), the fall (October), respectively. The diel fluctuation and seasonal dynamics of volatile organic compounds from P. chinensis leaves were determined by automatic static headspace and GC-MS (gas chromatography-mass spectrometry) technique. [Result]The released volatile substances mainly contained Monoterpenes of β-cis-ocimene, β-trans-ocimene, D-limonene, 3-carene, α-pinene, and β-myrcene, and a small amount of alcohols, ketones and esters. The terpenes accounted for more than 85% of the total volatiles. During a year, the release of terpene substances had a dynamic trend of summer (93.6%) > fall (89.2%) > spring (85.9%). The species of terpene substances were most in spring (59 kinds), followed by that in summer (52 kinds), and then in autumn (50 kinds). The released quantity of alcohols was most in spring, and followed by that in summer and autumn, and the released amount in summer and autumn was similar; Esters, alkanes and aldehydes were released the least in summer, and the released amounts in spring were more than that in autumn. However, ketone release quantity did not change significantly in different seasons. In terms of several major terpenes, the release quantity of beta-cis-Ocimene in different seasons was as the following: spring> summer> autumn, the released beta-Trans-Ocimene was autumn> spring> summer, the released 3-carene was summer > spring > autumn, while the α-pinene and β-myrcene remained unchanged. During a day, the relative contents of monoterpenes showed a trend of the first increased then decreased, and at 15:00, the released amounts generally reached the highest in the day, with smaller in morning and evening. As for several major terpenes, the release quantity of β-cis-ocimene, β-trans-ocimene and D-limonene reached the most in 15:00, regardless of in spring, summer or autumn; and the α-pinene was released the most at 15:00 in spring and autumn, while it was released the maximum at 12:00 in summer; The release quantity of β-myrcene remained uncharged all the time except for that at 18:00 in spring when it slightly dropped. The release quantity of 3-carene remained unchanged in spring and autumn, while it showed a trend of the first increased then decreased with the peak at 12:00 pm. [Conclusion]Monoterpenes were the main volatile substances released from P. chinensis leaves. The seasonal dynamic trends were summer> autumn> spring, and the diel fluctuation showed a trend of 15:00> 12:00> 18:00> 09:00> 21:00.

[Objective]As an important economic crop, the value of olive(Olea europaea) for health has been paid more and more attention. And the olive industry in China has reached a certain scale. Mislabeling and synonyms in introduced varieties have affected the development of China's olive industry. So there is a need to assess genetic variation of olive varieties in China. [Method]SRAP technology was applied to conduct genetic diversity analysis for 32 olive varieties from Xichang, Sichuan Province. 5 olive varieties among them were bred in China and 27 varieties were introduced. Genomic DNA was extracted for 32 olive varieties by the improved CTAB method. [Result]A total of 293 (90.75%) polymorphic bands were amplified by 25 pairs of primers and 11.72 polymorphic bands in average were amplified from each pair of primers. The most polymorphic bands (37) were amplified by primers M5E5. The expected heterozygoisty (H_e) varied from 0.804 to 0.958 (mean, 0.896), while the values of polymorphic information content(PIC) varied from 0.773 to 0.955 (mean, 0.884). The probability of identity (PI) varied from 0.004 to 0.067 (mean, 0.024). As the clustering analysis indicated, all varieties could be clustered into 3 groups and the genetic similarity (GS) varied from 0.59 to 0.89 (mean, 0.74). The highest genetic similarity between two varieties (‘Greece 3^#’ and ‘Pendolino’) was 0.89. Varieties bred in China were distributed in 3 groups. ‘Zhongshan 24’ was developed from seedling selection of ‘Ascolana Tenera’, which displayed high similarity in both morphology and genetics. This further proved the relations between varieties bred in China and introduced foreign varieties. ‘Mixaj I Dukat’-‘Mixaj’ and ‘Greece 3^#’-‘Pendolino’ were clustered together with high genetic similarity. The PCA analysis indicated that all varieties could be clustered into 3 groups explaining 20.8% of the total variation. Varieties of the group Ⅰ of PCA analysis were all contained cluster Ⅱ of UPGMA, indicating consistence between the two ways of analysis. [Conclusion]According to the morphology of different olive varieties (fruit mass, oil content, leaf shape etc.) and genetic (breeding background and genetic similarity etc.) data, the cluster of some introduced varieties were not in consistence with their geographical origins, probably due to both genetic and morphological data. SRAPs can be applied to olive genetic diversity analysis more simply and reliably. The introduced olive varieties displayed a genetic diversity, and there were confusions of variety names and high genetic variation due to environment effects. In the future, SRAP markers and other new molecular markers can be used to further analyze genetic diversity and germplasm identification. Moreover, new technologies of gene mapping and identification of gene functions can be also used to construct high-density genetic linkage maps. Traditional breeding and molecular markers should be integrated to accelerate the process of breeding.

[Objective]Quadrastichus erythrinae is an alien invasive gall-forming insect pest and specifically attacks Erythrina plants, a group of important ornamental plants worldwide. Since the pest invasion in 2004, these host plants have been heavily damaged in Hainan, China. Based on the morphological and anatomical characteristics, the gall development and its variation in structure at the five gall developmental stages were investigated. The five stages include the early growth phase, the later growth phase,maturation phase, and dehiscence, and the photosynthesis. [Method]Galled and ungalled, young and mature leaves were collected from potting Erythrina variegate grown in a laboratory in Hainan Normal University. For morphological studies, the weight, diameter, and height of the galls, and the size of the insect at the five stages were measured with the aid of the Motic Images advanced 3.2 microscope system. For histological studies, transverse sections of the samples were fixed in FAA, dehydrated in n-butyl series, and embedded in Paraplast. All the samples were sectioned into 10 m thickness and stained with astra blue and safranina. The anatomical structures of leaves (n=10 fields), petioles (n=10 fields) and the galls (n=10 fields) were observed with the aid of a clear camera coupled to a light microscope and Motic Images advanced 3.2 microscope system. [Result]The gall-midge females laid their eggs in young leaves. The young leaves, and the upper epidermis and spongy tissue were all thicker than the mature leaves and those tissues (P<0.01); However the upper epidermis and palisade tissue of the young leaves had less arrangement density than that in the older leaves (P<0.01); With the larvae development, the gall was increased rapidly firstly, later the speed of augmentation slowed down, and finally the gall decreased after adult insects left the galls; Plant organs began to change with the invasion of Q. erythrinae; The anatomical structure of the gall tissue formed gall-room, parenchyma layer, protective layer and epidermis layer from inside to outside, and the each layer of galls augmented firstly and then decreased slowly; The parenchyma layer served as the nutritive provider, and was significantly thickened at the third stage (P<0.05); Epidermis and protective layers that provided protection for the growth of larvae and pupae of Q. erythrinae were significantly thicker at the second stage (P<0.01). [Conclusion]Plant organs began to change with the oviposition of Q. erythrinae, and variations in gall structure were usually related to the host tissue age. Young tissues were generally more capable of reacting to gall induction than mature ones; the observation of five developmental phases of the gall proved that, while the gall external structure was determined by defensiveness, the internal structure diversification was probably related to nutritive supply. The results could well interprete the adaptive value of insect galls for the galling insect. Thus this study lays a foundation on which further experiments are conducted in an effort to determine the mechanism of gall formation in E. variegate.