Objective: The composition, dynamics and spatial distribution pattern of seed rain, soil seed bank and seedling germination of woody plants of 3 different Karst forest, types (evergreen and deciduous mixed broad-leaved forest, deciduous broad-leaved forest and evergreen broad-leaved forest) in Jinfo Mountain were studied in order to reveal the regeneration potential and development direction of Karst forest and provide theoretical basis for Karst forest management. Method: Seed rain receptors were randomly set up in each of the forest types and collected once every 15 days from the beginning to the end of seed falling, with a total of 8 collections. At the same time, samples of soil seed bank were collected from litter layer, 0-2 cm and 2-5 cm soil layers. The seeds collected from seed rain and seed bank were identified, and the classified into four categories of complete, moth-eaten, defect and mouldy seeds each of which was counted. Finally, the vitality of the complete seeds was identified by TTC staining. In May 2020, the species and quantity of seedlings were investigated. Result: The falling time and peak time of seed rain of the three forest types are basically the same. The seed rain of evergreen broad-leaved forest had the highest intensity, reaching 1 453 seeds ·m^-2, followed by deciduous broad-leaved forest and evergreen and deciduous mixed broad-leaved forest, and the proportion of vital seeds of the seed rain was significantly (P < 0.05) different among the 3 forest types, with an order of: evergreen broad-leaved forest (55.41%) > evergreen and deciduous mixed broad-leaved forest (47.41%) > deciduous broad-leaved forest (44.44%). The proportions of moth-eaten, defect and mouldy seeds to the total seed rain were in an order of: evergreen and deciduous mixed broad-leaved forest > evergreen broad-leaved forest > deciduous broad-leaved forest. During different periods (August and December), the total seed reserves in the soil seed bank were significantly (P < 0.05) different among the 3 forest types with an order of: evergreen broad-leaved forest > evergreen and deciduous mixed broad-leaved forest > deciduous broad-leaved forest. The soil seed banks of all the 3 forest types prior to the seed rain (August) were mostly concentrated in the 0-2 cm soil layer, followed by the 2-5 cm soil layer, with the least in litter layer. However, after the seed rain (December), the seed bank distribution of: the evergreen and deciduous mixed broad-leaved forest and the evergreen broad-leaved forest was in an order of 0-2 cm soil layer > litter layer > 2-5 cm soil layer, while that of deciduous broad-leaved forest was in an order of litter layer > 0-2 cm soil layer > 2-5 cm soil layer. There was a significant (P < 0.05) difference in the number of newly regenerated seedlings among the three forest types, with the largest number in the deciduous broad-leaved forest, followed by the mixed evergreen and deciduous broad-leaved forest and the evergreen broad-leaved forest. The species similarity of the 3 forest types was low among the seed rain, the seed bank and the regenerated seedlings. The similarity coefficient between the seed rain and the seed bank was the highest in the evergreen broad-leaved forest and the lowest in the deciduous broad-leaved forest. The similarity coefficient between the seed rain and the regenerated seedlings was the highest in deciduous broad-leaved forest and the lowest in evergreen broad-leaved forest. The similarity coefficient between the seed bank and the regenerated seedlings was very low in all the 3 forest types. Conclusion: The seed rain intensity, soil seed bank reserves and vital seed proportion of woody plants in Jinfo Mountain Karst forest are all large, and the forest community in this area has a strong foundation and potential for regeneration. However, there are significant differences in the seed rain, the soil seed bank and the seedling regeneration among different forest types. The number of regenerated seedlings of woody plant is the highest in the deciduous broad-leaved forest, but the lowest in the evergreen broad-leaved forest with the most abundant sources of seeds, which indicates that the habitat conditions of high canopy density and low soil water content are not conducive to regeneration. The study shows that the management of Karst forest needs to pay attention to the influence of forest type difference on seedling regeneration. Rational planning of stand structure, improving light, litter and soil conditions under forest, and reducing seed loss can provide good conditions for seed germination and seedling establishment of woody plants, therefore promoting the regeneration and restoration of Karst forest.

Objective: Contents of leaf nutrients of the main tree species in Tsuga chinensis forest were investigated to illustrate stoichiometric characteristics and resorption efficiency of nutrients of fresh and litter leaves of tree species with different life forms (deciduous and evergreen tree species), in order to reveal their responses to the different life forms. Method: The fresh and litter leaves of main tree species were collected in T. chinensis natural forest. The contents of carbon(C), nitrogen(N) and phosphorus(P) in leaves were determined, and their stoichiometric ratio and nutrient resorption efficiency were calculated. The standardized major axis estimation(SMA) method was used to study the allometric relationship among the fresh leaves of the main tree species in the T. chinensis forest. The effects of different life forms on the relationship between N and P contents in leaves were analyzed. Result: There was no significant difference in fresh leaf C content between deciduous and evergreen tree species, but the N, and P content of deciduous tree species was significantly higher than that of evergreen tree species (P < 0.05). there was no significant difference in the contents of C, N and P in litter leaves between the two life-forms in the natural mixed forest of T. chinensis in Wuyi Mountain. the C∶N and C∶P of fresh leaves in deciduous species was significantly lower than that of fresh leaves in evergreen species (P < 0.05), but their N: P was not different between the two life-types, C ∶N, N ∶P, and C ∶P of litter leaves were all significantly larger than that of the fresh leaves, but there was no difference between the two different life forms. There was a significant positive correlation between the N and P contents in the fresh leaves of evergreen tree species and a significant positive correlation of the N and P contents in the litter leaves between evergreen and deciduous tree species(P < 0.05), but the slope of the correlation function was not significant (P = 0.60), with a value of 0.73, and the N content of the litter leaves was positively correlated with that of the fresh leaves, but the P content not. There was no significant difference in leaf N and P resorption efficiency between deciduous and evergreen tree species, and both had a higher P resorption efficiency. Conclusion: The contents of N and P in fresh leaves was significantly higher of deciduous than evergreen tree species. No significant differences in N and P nutrient resorption efficiency were found between the two different life forms. Life form has no effect on the slope of N and P correlation in the leaf litter between evergreen and deciduous tree species. There are significant differences in leaf nutrient contents between different life forms, different nutrient acquisition strategies exist for different life forms.

Objective: The purpose of this study was to investigate the contents of organic carbon (OC), total nitrogen (TN), and total phosphorus (TP) and their stoichiometric characteristics in leaves of four typical plantation species (coniferous and broad-leaved life forms) in the alpine zone of the Loess Plateau in Qinghai, and their changes with the stages of the growing season (Ⅰ: May 15 to June 15; Ⅱ: June 15 to July 15; Ⅲ: July 15 to August 15) and the slope positions, and to provide a scientific basis for the management of forest in Qinghai. Method: The OC, TN, and TP in leaf samples of four typical plantation species (Larix principis-rupprechtii, Picea crassifolia, Betula platyphylla, and Populus cathayana) were measured by field manual sampling and indoor experimental analysis. The nutrient contents and stoichiometric characteristics were analyzed by normality test, one-way analysis of variance, Duncan multiple comparison, correlation analysis, detrended correspondence analysis, redundancy analysis, and Monte Carlo permutation test. Result: The mean values and variation range of the OC, TN, and TP contents in leaves of the four typical plantation species in the alpine zone of the Loess Plateau in Qinghai were 591.84 (571.19-605.67), 17.76 (7.14-27.62), and 1.47 (0.81-2.65) g·kg^-1, respectively. The coefficients of variation were ranked TP> TN> OC. The leaf TN content of the broad-leaved trees was higher than that of the coniferous trees. The leaf TN content and TP content of the broad-leaved trees were more affected by the stages of the growing season than that of the coniferous trees. The mean values and variation range of leaf C ∶N (OC ∶TN), C ∶P (OC ∶TP), and N ∶P (TN ∶TP) were 38.87 (26.04-97.73), 1 042.97 (667.53-1 971.00), and 28.32 (18.87-51.50), respectively. The coefficients of variation were ranked C ∶N < N ∶P < C ∶P. The leaf C ∶N and C ∶P of the broad-leaved trees were more affected by the stages of the growing season than that of the coniferous trees. Except for P. crassifolia, the contents of TN and TP in leaves of the other three tree species showed a very significant positive correlation (P < 0.01). The effects of stages of the growing season and life forms on leaf OC, TN, and TP contents and stoichiometric ratios of the four typical plantation species reached extreme levels of significance (P < 0.01), while the effect of slope positions was not significant (P>0.05). Conclusion: In the alpine zone of the Loess Plateau in Qinghai, the mean values of C ∶N and C ∶P in leaves of P. crassifolia were at a high level, while N ∶P was at a low level, indicating that the growth rate of P. crassifolia was relatively slow and the major reason was probably the limitation of TN. Attention should be paid to the supply of TN nutrient. Since the stages of growing season and the life form were two significant factors affecting leaf nutrient contents and stoichiometric ratios of the four typical plantation species (P < 0.01), both of them should be concerned carefully in the nutrient management in the alpine zone of the Loess Plateau in Qinghai.

Objective: In this study, the dynamic changes of non-structural carbohydrates (NSC) of Robinia pseudoacacia under NaCl stress was investigated, which is of great theoretical and practical significance for revealing its adaptation mechanism to NaCl stress and the management of R. pseudoacacia platation. Method: In this study, the 1-year-old R. pseudoacacia seedlings were used as the research object, and the relative growth rate, biomass allocation and NSC variation rules of the seedlings under different NaCl concentrations (0, 1.5‰, 3‰ and 4.5‰) were studied through a pot experiment. Result: 1) With the increase of soil NaCl concentration, the relative growth rate of ground diameter and height of R. pseudoacacia seedlings decreased significantly. With the increase of NaCl stress duration, leaf biomass decreased gradually, while root biomass did not change significantly. Resulting in a significant decrease in leaf biomass ratio, and a significant increase in root biomass ratio and root-shoot ratio. 2) The contents of NSC (soluble sugars and starch), in coarse roots, fine roots, stems and leaves were not significantly different when the soil NaCl concentration was in a range of 0, 1.5‰ and 3‰, but were significantly decreased when the soil NaCl concentration reached 4.5‰. Especially, the starch content of coarse roots was significantly higher than that of fine roots, stems and leaves. 3) Correlation analysis showed that relative growth rates of ground diameter and height of seedling were significantly positively correlated with leaf biomass ratio and soluble sugars of coarse roots, and negatively correlated with root biomass ratio and root-shoot ratio. There was a significant positive correlation between coarse root starch and fine root soluble sugar and stem soluble sugar, stem starch and stem soluble sugar, indicating that the dynamic changes of NSC affected the biomass allocation and the coordinated growth of organs, which is a vital index of R. pseudoacacia's adaptablity to NaCl stress. 4) The principal component analysis showed that the adaptability of R. pseudoacacia under NaCl stress could be simplified into three principal components: growth index, coarse root NSC and stem NSC, and the contribution rates were 43.05%, 15.99% and 14.65%, respectively and the cumulative contribution rate was 73.69%. Conclusion: NaCl stress significantly inhibits the growth of R. pseudoacacia seedlings. The decrease of NSC input to leaves and the increase of NSC input to roots lead to the decrease of seedling growth. Soluble sugars are the main form of NSC, influencing tree growth under salt stress. Coarse root is the main strorage organ of starch; while starch is not directly involved in tree growth but is the important source of soluble sugars. As a result, the allocation of root biomass and the coordination of NSC in seedlings are two important adaptive mechanisms for R. pseudoacacia growth under NaCl stress.

Objective: Natural rubber biosynthesis is the typical plant isoprenoid metabolic pathway. The MVA is one of the major metabolic pathways for providing the 5-carbon component units for the subsequent natural rubber or terpenoids biosynthesis. The farnesyl pyrophosphate, forming by the polymerization of two IPP molecules with one DMAPP molecule, is identified as the primer of rubber synthesis in nature. To characterize the farnesyl pyrophosphate synthases (FPS) in rubber-producing plants is of great assistance not only in illustrating the rubber biosynthesis mechanism, but also in providing a solid enzymatic foundation for natural rubber genetic breeding. Method: Homologues analysis was applied to investigate the primary amino acids and the secondary structure between these rubber-producing plants including rubber trees (Hevea brasiliensis). The two highly homologous FPS-encoding genes with high expression were selected to construct prokaryotic expressed vectors. The two rubber tree FPS genes expressed their recombinant products were purified and further confirmed by MALDI TOF mass spectrometry detection. After the in vitro enzymatic reaction assay, these two FPS proteins were supplemented to the in vitro rubber synthesis efficacy analysis. Result: Rubber tree harbored three predicted homologous FPS proteins with two conserved motifs 'DDIMD' and 'DDYXD' and similar tertiary structures. The amino acids similarity of the homologous proteins encoded by the two highly-expressed FPS genes was reached 95%, indicating the later gene copy events during its genome evolution. HbFPS1 and HbFPS2 genes can be correctly expressed in Escherichia coli, while the HbFPS 3 existed mostly in the inclusion body, reflecting the probable affection by the obvious difference of hydrophilicity or hydrophobicity in their N-terminal amino acids. The HbFPS1 and HbFPS2 proteins exhibited direct FPP synthesis capacity by using the precursor IPP and DMAPP despite the theoretical precursor GPP in the in vitro enzymatic reaction. Meanwhile, the addition of HbFPS1 or HbFPS2 also respectively increased the in vitro rubber synthesis efficacy in a dose-related manner by using the native rubber particles in the reaction system, and peak improvement was observed at 100 μg level. Conclusion: The amino acids differentiation may affect the catalytic activity between the two highly homologues redundant HbFPS1 and HbFPS2 proteins with the HbFPS3. HbFPS1 and HbFPS2 are indeed the exact functional enzymes that participate in the natural rubber biosynthesis process, especially harboring the ability to generate FPP by direct polyreaction of IPP and DMAPP per se. We establish an in vitro protein functional analysis platform via the natural rubber particles, and confirm the significant enhancement in the natural rubber synthesis efficacy by HbFPS1 and HbFPS2 enzymes when supplemented at an appropriate level. Fine-tuning the rubber tree HbFPS1 and HbFPS2 enzymatic activities will be conducive to the genetic improvement and breeding of novel rubber tree varieties with high quality and high yield.

Objective: Monitoring of biosafety of adult transgenic trees of Populus alba ×P. berolinensis in a field trial for successive years and assessment of possible ecological risks caused by transgenic P. alba ×P. berolinensis were conducted to provide a basis for evaluating the biosafety of transgenic poplar and soil environment of transgenic plants. Method: 11 years old transgenic trees of P. alba ×P. berolinensis, non-transgenic P. alba ×P. berolinensis(control), weeds and soil in the field trial established in Fangshan District of Beijing, leaves of seedlings under the roadside poplar beside the trial, and Kanamycin-resistant strain screened out from the soil were used for PCR amplification to detect stability and horizontal transfer potential of JERF 36 gene. The dilution plate method was used to quantify the soil microbes (including bacteria, actinomycetes and fungi) respectively for the 9-11 years old transgenic and non-transgenic poplars in the trial. Result: The exogenous gene, JERF 36 , was stable in the transgenic poplar, and no target gene fragment was detected in the weeds and soil in the trial, the roadside poplar trees, and the Kanamycin-resistant strain. There was no significant difference in the total number of microorganisms in the soil between the 9-11 years old transgenic and non-transgenic poplar trees. There were slight differences in the number of soil microorganisms of transgenic and the non-transgenic poplar trees among different years, with the same rank from June to August in 9 years old > 10 years old >11 years old. The number of bacteria, fungi and actinomycetes had no significant difference between transgenic and the non-transgenic poplar trees, with the same change tendency from 9 to 11 years old, i.e. rising first followed by falling in growing season. The total amount of microbial peaked in July and August, significantly higher than other months, and the number of bacteria and actinomycetes both peaked in August, while the fungi peaked in August (9-10 years old) or July (11 years old). Proportions of the three types of microorganisms in the soil of transgenic poplar trees were similar to that of the non-transgenic trees for all the years, in an order from the highest to the lowest of bacteria, actinomycetes and fungi. The proportions of the three types of microorganisms were slightly different among each other in different years, with no sudden increase or sharp decrease, indicating that the balance among the main microbial types was not broken by the transgenic poplar trees. Environmental changes such as differences in rainfall might be the main reasons for the differences in the quantity of microorganisms in different years. Conclusion: The exogenous gene stably exists in the transgenic trees of Populus alba ×P. berolinensis 11 years after planting, with no horizontal transfer to the surrounding environment, also no significant impact on the number or variety balance of soil microorganisms. Environmental change may be the major influential factor for the quantity difference. The slight differences of microbial quantity between the transgenic and non-transgenic poplar trees needs further studies by considering environmental factors.

This paper reports a kind of obligate pest that damages the leaves of Manglietia yuyuanensis in Fujian province. The pest is a new species of Tenthredinidae, Cladiucha huangbki Niu & Wei sp. nov. Its potential distribution area includes northern Guangdong, Zhejiang, Jiangxi and Hunan. Cladiucha huangbki is the most similar to C. megatheca Wei, but differs from the latter with smaller body; the female antenna clearly longer than twice head breadth with 22 + 3 antennomeres; malar space 0.4 times as long as diameter of median ocellus; the middle fovea shallow and without a deep pit; the lateral furrows of postocellar area distinctly divergent; the middle serrulae of female lancet flat; and the host plant is M. yuyuanensis. The mitochondrial genomes of three Cladiucha species have been sequenced. C. huangbki and C. punctata Wei are divergent in morphology, but similar in the mitochondrial genome. The COⅠ and other 11 protein-coding genes have high similarity, but the P distance of the two nad2 genes is 4.86%. This is the first reported case within Symphyta of Hymenoptera that the difference between the COⅠ genes of the closely related species of a genus is very small but the difference between the nad2 genes of them is distinct. In order to facilitate the identification of the sawfly pests on Magnoliaceae, a key for world Cladiucha species is provided.

Objective: To provide a reference for further transcriptomics studies of the yellow-spined locust, Ceracris kiangsu, the reference genes were screened based on different instars, different genders of adults and different tissues of C. kiangsu. Method: According to the transcriptome sequencing result, nine internal reference genes commonly used in insects, TUB, RPS27A, RPL10, AK, GAPDH, EF1A, RPS3, Actin, and 18S rRNA were chosen as candidates. The base sequences were obtained, and primers were designed after local Blast. GeNorm, NormFinder and BestKeeper were used to analyze the stability of the nine reference genes, and then the most suitable reference genes were screened according to the expression levels in different instars, genders of aduits, and tissues (antennae, head, labial palp, muscle tissue, testis/ovary) of adults. Result: Nine candidate reference genes of C. kiangsu were verified and reported for the first time, and they showed high homology (more than 70%) with the corresponding genes of other insects. The primers for the nine candidate reference genes all had good amplification efficiency (within 90%- 120%). In all samples, the expression level of 18S rRNA was the highest (C_t value = 10.78 ± 2.58, P < 0.05), and the difference in Actin expression level was the largest (C_t= 23.55 ± 3.84, P < 0.05). In analyzing the stability of the reference genes of C. kiangsu at different stages of nymphs, the top two of the three software were RPS3 and RPL10. Based on the analysis of different tissues, RPL10 was the most suitable reference gene suggested by GeNorm and BestKeeper, while GAPDH was most suitable one according the analysis of NormFinder. In terms of the analysis of different genders of the C. kiangsu adults, GAPDH and RPL10 were proved to be the two most suitable reference genes by the three software. Conclusion: RPL10 with stable and different expression under various conditions in C. kiangsu has bee screened as reference gene, which can be used as an internal reference gene for the research of transcriptomics and functional genomics for C. kiangsu.

Objective: This study aims to explore the temporal niche, spatial niche and spatio-temporal niche of dominant species of protozoa in the midstream and downstream of Lhasa River, and reveal the resource utilization status of dominant protozoa species and the relationship with to environmental factors, which provide a basis for further study on the interspecific interaction of protozoa communities and the adaptive mechanisms of protozoan to environmental change. Method: According to the characteristics of water enviroment in the midstream and downstream of Lhasd River, a total of 153 water samples were collected with plankton nets (aperture: 64 μm) at the seventeen sites in the midstream and downstream of Lhasa River in May, August 2015 and November 2016. We analysed replacement rate, niche width, niche overlap, ecological response rate and studied the niche of dominant protozoan species and the relationship with environmental factors through correlation analysis, redundancy analysis, cluster analysis and other method. Result: A total of 197 species of protozoa were identified, belonging to 2 phyla, 5 classes, 20 orders, 48 families and 75 genera, among which there were 5 dominant species of protozoa belonging to 2 phyla and 5 genera. The temporal niche width of dominant species is 0.378-0.695, the spatial niche width is 0.071-0.354, and the spatio-temporal niche width is 0.027-0.246. The dominant species have mainly low overlap in temporal niche, spatial niche and spatio-temporal niche. The sum of temporal ecological response rate of dominant species was 0.449, the sum of spatial ecological response rate was -6.972 and the sum of spatial and temporal ecological response rate was -0.107. The redundancy analysis showed that the water temperature significantly affected the distribution of protozoa dominant species in the lower reaches, and dissolved oxygen and total phosphorus significantly affected the distribution of dominant species in the midstream of Lhasa River. Conclusion: There are seasonal and regional differences of dominant species of protozoa, that temporal, spatial and spatio-temporal niche width and niche overlap is low in midstream and downstream of Lhasa River. The dominant species of protozoa were sensitive to changes in the water environment, and their distribution is significantly effected by the water environment. The protozoan community ecosystem was relatively fragile.

Objective: This study was carried out to understand the phenological changes of temperate deciduous broad-leaved forest and its relationships with meteorological factors in order to improve the accuracy of vegetation carbon sequestration model and regional carbon sequestration simulation. Method: The relative green chromatic coordinate (Gcc) was calculated from the continuous images produced by digital cameras in a deciduous broad-leaved ecosystem in Songshan, Beijing in 2019. The relationships between Gcc and environmental factors were analyzed using Pearson correlation analysis. Furthermore, phenology stage was estimated using Gcc, normalized difference vegetation index(NDVI) and gross primary productivity (GPP) by eddy covariance, then their differences were compared. Result: The correlation coefficients between Gcc and air temperature (T_a), soil temperature (T_s), soil volume water content (SWC), photosynthetically active radiation (PAR), vapor pressure deficit (VPD) and precipitation (P) were 0.88, 0.86, 0.29, 0.45, 0.65 and 0.25, respectively. The starting day of year of growing season (SOS) dericed from Gcc, NDVI and GPP was 129, 116 and 110, respectively. The ending day of year of growing season (EOS) was 277, 277 and 283, respectively. The length of growing season (LOS) was 148, 162 and 173 days, respectively. Conclusion: During the study period, vegetation growth was mainly affected by temperature, PAR and VPD. Precipitation had a pulse effect on Gcc. The digital camera and SRS-NDVI could sensitively capture the dynamics in vegetation growth. The accuracy of digital camera for late growth might be higher than that for early growth.

Objective: In order to verify the usability of destructive sampling data in 3-PG(physiological principles in predicting growth) model parameterization, this study predicted the growth of Larix olgensis using the 3-PG model calibrated by destructive sampling data, which can help to expand the data source of 3-PG model parameterization and provide a reference for model data selection. Method: Taking L. olgensis plantation in Mengjiagang forest farm as the study object, the destructive sampling data collected in 2019 was calculated to simulate the continuous observation data. The biomass of foliage, stem, and root, and stand volume were calculated based on the relevant biomass formulas. According to the sensitivity analysis results, the 3-PG model was parameterized by direct calculation, reference, and iterative fitting. Then the modeling results were verified by continuous observation data and fixed plot data, and the model output was regressed with observed data. Result: The results showed that the fitting accuracy was very high, and the model output data could well reflect the growth of the stand (n=138). The determination coefficient (R²) values of DBH, the ratio of foliage to stem biomass, stem biomass, total biomass and volume were all above 0.95 (P < 0.01). In contrast, the root biomass had a relatively lower fitting accuracy (R²=0.88). The model's predicting accuracy was verified by continuous observation data and fixed plot data. High correlations were observed between the model output and continuous observation data (n=140) and fixed plot data (n=87). The R² of all values ranged from 0.81 to 0.97 (P < 0.01). According to the sensitivity analysis results, foliage∶stem partitioning ratio at DBH=20 cm (pFS20) and Maximum fraction of NPP to roots (pRx) showed high sensitivity to DBH, root biomass, stem biomass, and volume. Conclusion: 3-PG model calibrated by destructive sampling data had a relatively high fitting accuracy and prediction accuracy. The results of this study would expand the data source of 3-PG model parameterization and provide a new basis for the 3-PG model to simulate the growth of L. olgensis plantation.

Objective: In order to provide data for the refined design on fire resistance of timber structures and the evaluation on residual bearing capacity of structural members exposed to fire, the parallel-to-grain tangential shear strength of heated wood within structural member with a large cross section under the protection of the outermost charred layer was tested, and its degradation model was built. Method: Imported Larix gmelinii and Pseudotsuga menziesii, and domestic fast-growing Populus spp. with a high strength grade and potential application in timber structure, were selected as the research objects. A test chamber filled with nitrogen was used in this study to simulate the oxygen-free conditions. The temperatures were set to nine levels, such as 20, 50, 70, 110, 150, 200, 220, 250 and 280 ℃. As many as 216 specimens were tested to determine the parallel-to-grain shear strength of wood specimens at temperatures between 20 and 280 ℃ under oxygen-free conditions. The main chemical compositions of wood specimens at 150, 180 and 220 ℃ was also determined. Result: At room temperature, the shear strengths of Larix gmelinii, Pseudotsuga menziesii, and Populus spp. wood specimens were 9.65, 8.94 and 9.48 MPa, respectively. When the temperature reached 150 ℃, the shear strength of Larix gmelinii, Pseudotsuga menziesii, and Populus spp. of wood specimens decreased to 60.7%, 68.0% and 65.6% of the initial values, respectively. The shear strength of wood specimens decreased faster, as the temperature was 150 ℃ and higher. The shear strengths of Larix gmelinii, Pseudotsuga menziesii, and Populus spp. of wood specimens were determined as 1.05, 0.91 and 0.61 MPa at 280 ℃, respectively, which were only 9.0%, 10.2% and 6.4% of the initial values. The thermal stability of cellulose was the highest and that of hemicellulose was the lowest among the main chemical compositions within wood. The hemicellulose contents of Larix gmelinii, Pseudotsuga menziesii, and Populus spp. of wood specimens were 25.3%, 25.7% and 16.3% at room temperature, respectively. At 150 ℃, hemicellulose started to be decomposed and its content decreased by 1.3%-9.1%. Hemicellulose was decomposed rapidly at 200 ℃, and its content decreased by 29.4%, 18.6% and 25.9%, respectively. The degradation on parallel-to-grain shear strength of wood specimens was attributed to the serious pyrolysis of hemicellulose at high temperature. With the increase of temperature, the effects of wood density on parallel-to-grain shear strength gradually decreased. The ratio of shear strength to wood density was determined as 14.2 MPa·(g·cm^-3)^-1 at room temperature, and decreased to 1.1- 3.1 MPa·(g·cm^-3)^-1 at 200 ℃ and above. The degradation on relative shear strength of three wood species was similar with each other at elevated temperatures. Conclusion: High temperature might be negatively related with parallel-to-grain shear strength, causing by the reduction in hemicellulose content. The reduction factor of wood shear strength at a high temperature is less than that in European standard due to the oxygen-free conditions used in this study. Based on the test data, a bilinear model of wood parallel-to-grain shear strength deterioration at a high temperature was proposed.

Objective: This paper was proposed to reveal the effects of boiling treatments on the hygroscopicity and chemical compositions of moso bamboo and provide technical references for bamboo modification. Method: The bamboo samples were treated in the boiling water (with the quality ratio of bamboo/water was 1∶100) for 4 h. The dynamic vapour sorption (DVS) was used to study the dynamic moisture adsorption curve, and the experimental data were analyzed by Hailwood-Horrobin(H-H) model. Meanwhile, the microstructure chemical compositions and crystal parameters of bamboo were investigated by scanning electron microscopy(SEM), Fourier transform infrared spectrometer(FTIR), X-ray photoelectron spectroscopy(XPS) and X-ray diffraction(XRD). Result: The results showed that the boiling-treated bamboo had lower equilibrium moisture contents(EMC) than those of the raw bamboo when the relative humidity(RH) was higher than 50%. The H-H model analysis showed that the monolayer moisture content increased, while the polymer moisture content decreased for the boiling-treated bamboo when the RH was higher than 35%. As indicated by SEM images, the parenchyma cell wall shrank after treatment, which decreased the number of micro-pores, and consequently decreased the polymer moisture content. Meanwhile, the hemicellulose was partially degraded as indicated by the chemical composition content analysis. The FTIR analysis showed that the OH, CO groups of boiling-treated bamboo increased, which increased the monolayer moisture content. The XPS results showed that the polysaccharose degraded, and the fatty acid, fat and phenols moved to the surface of bamboo. The XRD analysis indicated that the amorphous region was changed, while the width of crystallite in crystal region and the crystallinity increased. Conclusion: The sorption behavior of bamboo decreased after boiling treated for 4 h, whereas its dimensional stability was improved. The changes in the micro-morphology of bamboo cell wall and chemical compositions had great effects on the water sorption properties of bamboo.

After natural evolution of history, subtle multi-level structure and excellent interface design have been formed inside bamboo. Rigid vascular bundles are gardenly and evenly distributed in flexible parenchymal cells, and a natural "island-chain structure" has been built, which not only offers high strength and toughness, but also enhances energy absorption and damping effect to resist natural disasters (rain, snow and wind), through the deformation of parenchymal cells and void structures, as well as crack deflection of intercellular layer. This paper was conducted to describe the vibration damping performance of bamboo and analyze the action mechanisms of environmental factors (temperature and humidity) upon such performances, from the two aspects of multi-scale structural characteristics (macro-micro) and chemical components (linear cellulose molecular chain-amorphous lignin polymers). Further, the vibration damping mechanisms of bamboo-based composites were summarized. The structure and technological characteristics of bamboo-based damping composites were analyzed, and the effects of four kinds of laminated structures (basic damping, impact damping, lightweight damping and quiet damping) on vibration damping properties of bamboo-based composites were also obtained among the three current widely-used assembly patterns of wood/bamboo, bamboo/plastic, and bamboo fiber/rubber particle. The application prospects of bamboo-based damping composites were discussed in the fields of sports, architecture, transportation and electronic information, according to the integrated design principle of "material-structure-function". The general scientific problems and key technologies those need to be solved urgently were raised in the end of the paper, towards biological vibration damping characteristics of bamboo, regulatory mechanisms of bamboo-based damping composites, research and development of novel intelligent bamboo-based damping material, and product standardization. Bamboo-based damping composites possess the function of energy absorption, energy consumption reduction, anti-vibration and noise reduction, which is of great significance for the prevention of noise and vibration pollution in the fields of construction, transportation and machinery.

Objective: This study presents an analysis of history, paths and driving forces of the development of forest parks in China in the past 40 years and a summary of practical implications in order to provide historical evidences and a theoretical basis for the development of forest parks. Method: In combination of literature analysis, history study and comprehensive analysis, the development of forest parks was integrated into the macro context of China's social economic development, the development stages of forest parks were identified in the context of strategic transition of both national and forestry sectoral development, and evolution of forest parks. Combining quantitative analysis of the changes in the number of forest parks, sources of construction investment, and average wages of employees, the internal logic of the development of forest parks was summarized. Result: 1) In the past 40 years, forest parks in China have gone through four stages: "diversification projects of forestry operation" (1982—1991), "the third industry of forestry"(1992—1997), "multi-dimensional development of green forestry industry" (1998—2010), and "protected natural areas and social public services" (2011—present). 2) The evolutionary path of forest parks in China in the past 40 years can be summarized as follows: property change from "tourist destination" to "protected natural areas", function change from "economic industry" to "social public services", value change from "for economic benefits" to "for green" to "for responsibility" and model change from "closed" to "open" to "integration". Conclusion: 1) The main reasons for the evolution of forest parks in China in the past 40 years can be attributed to the revolution for social justice, the vision for ecological sustainability and expectation of "good life". 2) Forest parks in China have the following problems: the management failure caused by lack of government leadership, restrictions by the "two-in-one" management system of state-owned forest farms, the misalignment of the roles of managers and operators, the new changes brought about by "reform of the state-owned forest farms" and "development of protected natural areas system", and the absence of relevant laws. 3) In the future, the management work of forest parks in China will be focused on: harmonization with "development of protected areas system with the mainstay of national parks", gradually establishing a diversified financing system with public financial support as the mainstay, harmonizing the "two in one" management system of state-owned forest farms, promoting the separation of management rights and operation rights, and improving legal system relevant to forest parks.

Objective: In this paper, we investigated the soil consolidation performance and anti-vibration of polymer soil consolidation agent, and explored the application technology of polymer soil consolidation agent in seedling transplanting, by which this study aimed to form a new technology of seedling transplanting to gradually expand the application of polymer to the ecological environment engineering of afforestation and greening. Method: In this paper, konjac glucomannan (KGM) and chitosan (CA) were used as the main raw materials and polyvinyl alcohol (PVA) was used as assistant to prepare environmental-friendly soil consolidation agent through polymer blending technology. The characteristic soil in North China—cinnamon soil was taken as the research object, the soil was prepared into soil column samples by moulds, and the prepared binary blend KGM/CA soil consolidation agent was evenly spread on the soil column, and after drying, a hard film formed on the surface of the soil column. In order to test whether the compression resistance and the anti-vibration performance of consolidated soil columns can meet the requirements of seedling transplantation in the actual transportation process, two different test methods were used to simulate the transportation anti-vibration of consolidated soil column. Finally, the seedlings of mulberry, Sabina chinensis and Euonymus japonicus were as transplanting objects to explore the application of blending soil consolidation agent in seedling transplanting. Result: The results showed that when the concentration of acetic acid solution was 20%, the pH of the glue was 4.5, the blending temperature was 40 ℃ and the content of KGM, CA and PVA were 4.5%, 4.5% and 6.0% in the prepared of KGM/CA/PVA ternary blend adhesive, the formulation of consolidating agent had the best consolidation effect on soil column and the consolidated soil column had the best anti-vibration performance in transportation. Conclusion: By testing the anti-vibration of consolidated soil columns with two different test methods, it has been found that the prepared KGM/CA and KGM/CA/PVA blend soil consolidation agent meet the requirements of consolidated soil balls. Through the preliminary application of the blend soil consolidation agent in the transplanting process of mulberry seedlings, Sabina chinensis seedlings and Euonymus japonicus seedlings, it is found that the blend soil consolidation agent has good consolidation effect on loam and sandy soil. In addition, the application of this kind of consolidation agent not only makes the transplanting process of seedlings faster, and ensures the survival rate of transplanted seedlings, but also has no adverse effect on the growth of seedlings.

Objective: In this study, the effects of different thinning intensity on plant growth, photosynthetic performance of different canopies, grain yield and oil quality of high density oil tree peony 'Fengdan' were investigated, which aimed to provide theoretical basis and technical support for accurate promotion and sustainable utilization of oil tree peony plantation. Method: This experiment was conducted in Qinyang experimental base of Henan Province, where the 'Fengdan' peony plantation was planted in October 2013. The initial planting density was 57 000 trees·hm^-2. In 2017, the 'Fengdan' peony entered the high-yield period, and when the fruits were ripe, it was founded that shading resulted in the death of the weak seedlings under high density condition. The actual density of the seedlings was 46 800 plants·hm^-2. In March 2018, after bud sprouting, thinnings were conducted with different intensities of 0% (CK), 17% (A), 35% (B), 47% (C) and 62% (D), respectively. The growth status, canopy photosynthetic parameters and yield traits and other indexes of plants were measured in 2019. Result: 1) Thinning had significant effects on the growth status, photosynthetic characteristics, grain yield and quality of 'Fengdan' (P < 0.05). The leaf area of the plant increased by 7.0%, 11.9, % 21.2% and 25.1% compared with the CK for the thinning intensities of A to D. The crown width, number of flowers, flower diameter, number of new leaves, leaf angle and number of new branches of plants showed the same change trend, while the tendency of plant height was the opposite. 2) Contents of leaf chlorophyll and soluble protein, rate of net photosynthetic (P_n), activities of SOD and CAT in the canopy layers were as follows: upper > middle > lower. The change of MDA content of leaves displayed opposite trend. Thinning significantly improved canopy light energy distribution and leaf photosynthetic performance. 3) The number of fruits, the number of grains and the quality of fruit pods per plant gradually increased with the increase of thinning intensity. The 100 grain mass and grain yield first increased and then decreased. The effect of 47% thinning intensity was the best, which grain yield was 47.97% higher than that of CK, and also significantly higher than other treatments (P < 0.05). There were not any differences in the fatty acid composition and content of tree peony kernel, but the total VE content first increased and then decreased with the thinning intensity. The components and content of VE in tree peony kernel treated with 47% thinning intensity were higher than those of other treatments, and the crude fat, starch and protein contents of the kernel also changed significantly with different thinning intensity. Conclusion: Reduction of the population density of oil tree peony through thinning can adjust the distribution of canopy light energy under growth stages, improve individual nutritional status and reduce space competition pressure, and maintain high and stable production performance of oil tree peony. It is most beneficial to improve the population structure of 'Fengdan' plantation by thinning in the range of medium intensity. The results suggest that thinning is an effective measure to promote photosynthetic performance, grain yield and quality of tree peony 'Fengdan'.

Objective: A transposon is a repeat fragment of DNA that can jump in the genome of an organism. According to the mechanism of transposition, transposons are divided into retrotransposons with "copy-paste" mode and DNA transposons with "cut-paste" mode. According to the integrity of the structure, the transposon can be classified into autonomous transposon and non-autonomous transposon. The autonomous transposon has a complete transposase and can independently produce transposase. The transposase of the non-autonomous transposon is incomplete, but contain necessary transpositional elements. The non-autonomous transposon can transpose under the assistance of the transposase from the autonomic transposon. Mariner-like element(MLE) is a kind of DNA transposons that are widely distributed in eukaryotic genomes, with the transposition mode of "cut-and-paste". Previous studies have shown that MLE transposons have great application in the fields of transgene, gene function analysis, gene therapy and so on. In order to reveal the distribution pattern and evolution dynamics of MLE transposons in the evolution of Phyllostachys edulis, the genome-wide mining of the MLE transposons in P. edulis genome were conducted. The distribution and deletion characteristics of autonomous MLE and non-autonomous MLE in the P. edulis genome were studied. Method: Utilization of the MLE transposon sequences of rice, soybeans and P. edulis, with the IRF, Blast and Fasta software, according to the specificity of TIR (Terminal Inverted Repeats) of MLE transposon and its encoding enzyme, the full-length intact MLE transposons were identified in P. edulis genome. According to TIR of the full-length intact MLE transposons, the corresponding non-autonomic MLEs were characterized. The distribution characteristics of autonomous and non-autonomous MLEs and the deletion patterns of non-autonomic MLE structures were analyzed. Result: Two intact autonomous MLE, PhV2MLE1A and PhV2MLE2A, were identified in this study. PhV2MLE1A is 3 950 bp in length, encodes 414 amino acids, and has a 30 bp length TIR. PhV2MLE2A was 12 990 bp, encodes 373 amino acids, and has 49 bp length TIR. According to the similarity of the TIR structure, two non-autonomous transposons corresponding to two autonomous MLEs were identified. In this experiment, two autonomous MLEs with complete structures and their corresponding non-autonomous transposons were obtained. At the same time, it was found that the structural deletion of different non-autonomous transposons was irregular. The distribution of MLE in the P. edulis was random, and the insertion preference was between the conservative sequence TA. Conclusion: A large number of MLE transposons were distributed in the genome of P. edulis. Most of MLE transposons lost their transposable activity due to the lack of transposases in the evolutionary process.