Latest Accepted Articles

Display Method:
Response of Nitrogen Mineralization in Soil Aggregates to Changes in Soil Moisture and Temperature in the Three Gorges Reservoir Area's typical Plantation
Chen tian, Cheng Ruimei, Shen Yafei, Wang Lijun, Xiao Wenfa, Zeng Lixiong, Sun Pengfei, Zhang Meng, Li Jing
, Available online  , doi: 10.12403/j.1001-1498.20230247
Objective Rising temperatures and precipitation have become challenges. In order to investigate the effects of climate change on soil nitrogen (N) dynamics in forests of the Three Gorges Reservoir area and to provide a basis for predicting changes in soil nutrient cycling in this area and enhancing forest productivity. Method The soil was sieved into large macroaggregates, coarse aggregate, small macroaggregates, and microaggregates (particle sizes: 8000-2000, 2000-1000, 1000-250, and <250 μm) in a mixed plantation of Pinus massoniana-Quercus variabilis. Differences in net N conversion of aggregates were observed at soil moisture of 40%, 60%, and 80% of the maximum water holding capacity in the field (named 0.4 FCW, 0.6 FCW, and 0.8 FCW), and at temperatures of 5°C, 15°C, 25°C, and 35°C using indoor incubation methods. Results The levels of soil organic matter (SOM), total N and microbial biomass carbon (C), and nitrogen were higher in small-size aggregates with larger specific surface areas, while available phosphorus (P) was significantly lower. The rates of net nitrification and net N mineralization of aggregates gradually increased with decreasing particle size, with net nitrification contributing more than 85% of net N mineralization. The rates of net nitrification and net N mineralization of aggregates first increased and then decreased with the increase of soil water moisture and temperature, and the maximum values appeared at 0.6 FCW and 25 ℃. The overall net ammonification, net nitrification, and net N mineralization rates of aggregates of different particle sizes were most sensitive to temperature increase at 0.60 FCW and 15°C/25°C. By developing a quadratic equation, the optimum soil moisture and temperature for the net ammonification rate were 0.70 FCW and 23.0°C, and the optimum soil moisture and temperature for the net nitrification and net nitrogen mineralization rates were 0.58 FCW - 0.60 FCW and 24.5°C - 27.5°C. Conclusion The physical structure of aggregates protects organic N from decomposition in the plantation in the Three Gorges Reservoir area. Rising temperatures and precipitation promote net N transformation in the soils, which is conducive to improving the N supply capacity of the soil; However, there is a risk of soil organic matter, N loss, and P limitation over the long term, so that monitoring and fertilizer measures can be carried out if necessary.
Research Progress in the Optimal Rotation of Forest Plantations Based on Experimental data
LIU Lin, SUN Hong-gang, WANG Yu-hua, ZHANG Jian-guo
, Available online  , doi: 10.12403/j.1001-1498.20230321
Although the study of forest rotation has attracted the attention of many scholars both domestically and internationally, there are still divergent opinions on the connotation of optimal forest rotation, the criteria for determining the optimal forest rotation, the criteria for determining the rotation, and the impact of related variables on the optimal forest rotation, which cannot provide a solid theoretical basis for developing a cultivation model for improving forest plantations. This paper summarized the research results on determining the optimal forest rotation, and used experimental data of Chinese fir plantations to demonstrate the different criteria, methods, and influencing factors in determining the optimal forest rotation. It also provides prospects for future research directions.
Spatial Structure of an Old-growth Oak Forest on Karst Terrain
LUO Xiu-qiong, HE Ji-an, LI Yuan-fa
, Available online  , doi: 10.12403/j.1001-1498.20230213
Objective To investigate the distribution pattern, species association and marker characteristics of karst oak old-growth forests, and to explore the role of vertical stratification in maintaining biodiversity in karst forests. Method A 200 m × 110 m fixed plot was established in an old growth karst forest (> 300 years) in the Nanpanjiang River basin, southwest China. Trees were divided into overstory and understory based on height and species composition. Relationships between diameter class and species abundance, and between diameter class and richness were analyzed by negative exponential function. The distribution patterns of overstory, understory and their main populations were analyzed by pair correlation function g(r), and spatial correlations between overstory and understory, and their main populations were also analyzed. The mark character of tree species and tree size were detected by mark correlation function kmm(r). Result (1) The diameter distribution of the stand, over-story and understory all showed an inverted J-shaped pattern. Species richness of the stand and understory decreased with increasing diameter classes, while that of the overstory increased first and then decreased; (2) The overstory exhibits regular or random distribution on most scales, and only exhibits aggregation distribution on small scales (r = 0~1 m, 4~6 m). The understory had higher aggregation intensity at large scale when compared to the overstory; (3) Random correlation dominated the overstory and understory, and their major populations. Only a few pairs had positive or negative correlation at small scale (r = 0~2 m); (4) The stand and understory shared a characteristic of conspecific aggregation at all scales, and their intensity were obviously higher than that of the overstory. Tree sizes of the stand and overstory differentiated obviously and small trees were strongly aggregated. The understory contained a similar size of small trees that were randomly distributed at most scales. Conclusion These results suggest that vertical stratification largely determine species composition, abundance, distribution pattern and the spatial association of overstory and understory, which plays an important role in species coexistence and diversity maintenance.
Effects of Low Temperature Stress on Leaf Photosynthetic Physiology and Antioxidant Characteristics in Mangrove Plants Seedlings with Different Cold Tolerance
XU Ming-hai, FENG Yu, TONG Yu-yan, YUE Dan-fei, ZHANG Hui-yu, ZHENG Chun-fang
, Available online  , doi: 10.12403/j.1001-1498.20230302
: Objective This study investigates the physiological response of two different cold-tolerant mangrove plant species to low temperature stress, which provides a theoretical basis for studying on cold resistance of mangrove. Method Based on the cold-tolerant variety Kandelia obovata and the non-cold-tolerant variety Lumnitzera littore , three temperature treatments were set for treatment, including 25 ℃/20 ℃ (day/night), 24 hours at 7 ℃/4 ℃ (day/night), and 48 hours at 7 ℃/4 ℃ (day/night). The differences in the of photosynthetic parameters and fluorescence characteristic, antioxidant capacity, chloroplast ultrastructure of two mangrove seedlings were compared and analyzed. Result Low-temperature stress inhibited the growth and photosynthesis of L. littore seedlings but had less effect on K. obovate. After 48 hours of low-temperature stress treatment, the activities of superoxide dismutase (SOD) and peroxidase (POD) in the leaves of L. littore seedlings were reduced, but the content of superoxide anion (O2·), malondialdehyde (MDA) and hydrogen peroxide (H2O2) in L. littore seedlings were increased. It was also observed that the leaf stomata were closed, and the contents of photosynthetic pigments were decreased. Additionally, the ultrastructure of the chloroplast was damaged, which eventually led to a decrease in the net photosynthetic rate (Pn), stomatal conductance (Gs), maximum photochemical efficiency (Fv/Fm), actual photochemical efficiency (ΦPSII), photochemical quenching coefficient (qP), and non-photochemical quenching coefficient (NPQ) of the leaves. Under the same low-temperature stress, the photosynthesis of K. obovata seedlings’ leaves was also inhibited, but the decrease in leaf Pn was approximately 79% of that observed in L. littore. Conclusion K. obovata exhibits stronger cold tolerance than L. littore, possibly because K. obovata can not only maintain higher stomatal opening, photosynthetic pigment content, and POD activity, reducing the damage to chloroplast ultrastructure, but also regulate energy dissipation to alleviate PSII photoinhibition, thereby reducing the damage caused by low-temperature stress to membrane lipid peroxidation. Consequently, K. obovata maintains its robust photosynthetic capacity.
Promoter Functional Analysis of the Key Gene PsDFR Involved in Paeonia suffruticosa Anthocyanin Biosynthesis
ZHOU Lin, YUAN Meng, Qi Yu, ZHANG Meng-jie, WANG Yan
, Available online  , doi: 10.12403/j.1001-1498.20230270
Objective To analyze the cis-acting element and activity of the tree peony anthocyanin biosynthetic key gene PsDFR promoter for further research on its function and regulation mechanism involved in tree peony flower coloration. Method The genomic DNA extracted from the petals of tree peony ‘Hei Hua Kui’ was used as a template. PsDFR promoter was isolated by genomic walking method. The cis-acting elements of promoter were analyzed and predicted through Bioinformatics online software. Five different length of deletion fragments were fused with GUS gene to construct promoter-reporter vectors, and then were transiently expressed in tobacco leaves. The activities of deletion promoters and their response to different stress treatments such as Abscisic acid (ABA), Methyl jasmonate (MeJA) and light were analyzed by GUS staining and GUS activity assay. Result A 1 687 bp sequence of PsDFR promoter was isolated. The results of bioinformatics analysis showed that the promoter contains multiple cis-acting elements associated with light signals, hormone response, stress response, and tissue-specific expression, indicating that the expression of PsDFR may be regulated by various signals such as light signaling, plant hormone and stress. GUS staining and quantitative analysis of GUS activity showed that GUS activities decreased gradually with decrease of the length of PsDFR promoters, and the region of -1 623 bp to -916 bp played an important role on the activity of the PsDFR promoter. The GUS activities were inhibited significantly by MeJA or dark treatment, and were induced obviously after light restoration. And core regulation region involved in ABA-response might be located between -443 and -76 bp. Conclusion PsDFR promoter contains multiple cis-acting elements associated with light signals, hormone response, stress response, and tissue-specific expression. Its activity is positively regulated by light and negatively regulated by MeJA. The region of -1 623 bp to -916 bp is important for the activity of the PsDFR promoter, and -443 and -76 bp is the core region in response to ABA treatment. This study provides a reference for further revealing the regulatory mechanism of PsDFR response to environmental signals involved in tree peony flower coloration.
Relationship between Tree Trunk Sap Flow and Meteorological Factors from Synchronous Data
MA Ze, SONG Wei-feng, XU Xiao-qing, CHU Ya
, Available online  , doi: 10.12403/j.1001-1498.20230131
Objective Trunk sap flow is an important physiological indicator for the study of plant transpiration water consumption, and both tree species and meteorological factors are key influencing factors. This study aims to remove the limitation of tree species factor and explore the relationship between tree trunk sap flow and meteorological factors. Method Based on ten tree species in 3 forest stands in the water source area of Hani Terraces, their trunk sap flow rates were measured by using thermal dissipation probe (TDP) technology, and the relationship between synchronized data and meteorological factors were analyzed. Result Seven abnormal synchrony data were found from 7 779 tree trunk sap flow rate data in secondary deciduous broadleaf and primary evergreen broadleaf forests, and these abnormal synchrony data showed synchronous consistency across tree species; Further correlation analysis showed that the sudden increase in solar radiation was the main cause of the synchronous increase in sap flow rate, while rainfall was the main cause of the synchronous decrease in sap flow rate, and changes in both could lead to changes in other meteorological factors, which could affect the trunk sap flow rate; There was a certain time lag effect between tree trunk sap flow and meteorological factors: under abnormal climate conditions, sap flow lagged solar radiation by 0~30 min and was ahead of saturated water vapor pressure difference, with air temperature and humidity of 0~60 min, and the lag or advance time was much smaller than the time of each tree species under normal climatic conditions. Conclusion Tree trunk sap flow is regulated by a combination of meteorological factors such as solar radiation or rainfall, with solar radiation having the most pronounced effect. The paper may provide a scientific basis for studying the relationship between transpiration and meteorological factors in trees at the physiological-ecological level.
Effects of Foliar Spray of Selenite on Metabolome in Leaves of Torreya grandis Seedlings
CHEN Zhen-sheng, LI Ai-hua, DU Shi-ping, HUANG Pei-geng, XU Xiu-huan, NING Bo-lin, LI Wen
, Available online  , doi: 10.12403/j.1001-1498.20240012
Objective To investigate the effects of foliar spray of selenite on metabolome in the leaves of Torrey grandis seedlings and changes in levels of secondary metabolites in the leaves. Method Sodium selenite of 100 μg·L−1 was sprayed to the leaves of 2-year-old seedlings of T. grandis at an interval of 15 d. Fifteen d after the second spraying, one-year-old leaves were harvested for metabolome analysis. Result The results showed that there were 909 differential metabolites between treatment group and control under positive ionization mode, with 69 metabolites of significant changes (27 metabolites up-regulated and 42 metabolites down-regulated). Under negative ionization mode, 433 differential metabolite occurred between treatment group and control, with 43 differential metabolites of significant changes (11 metabolites up-regulated and 32 metabolites down-regulated). Some metabolites beneficial to human health increased significantly in the treated leaves of T. grandis seedlings, such as plantagoside (increasing 2.827 times as control), ligustilide (increasing 2.524 times) , 6-sialyllactose (increasing 2.021 times), and azilsartan (increasing 1.931 times). Conclusion The results indicate that selenite foliar application on the leaves of T. grandis can increase biosynthesis of beneficial metabolites and accumulation in their leaves.
A Bibliometric Study on the Restoration and Carbon Sink Potential of Damaged Ecosystem in Mining Area
ZHANG Yu-ang, LI Ya-tong, DU Zhong-yu, QI Xin-hua, HOU Hong, CHEN Guang-cai
, Available online  , doi: 10.12403/j.1001-1498.20230296
Objective Mining activities have a detrimental impact on the environment, both in China and globally, leading to pollution, ecosystem damage, and risks to human health. The restoration and remediation of damaged ecosystems in mining areas present significant challenges, particularly in the context of China’s commitment to carbon neutrality. Method This study analyzed 914 literature sources published between 2010 and 2022, focusing on four key aspects of ecological restoration in mining areas: evaluation of damaged ecosystems, ecological restoration technology, carbon source/sink potential, and monitoring technology. Result There had been a shift in the approach to restoring damaged ecosystems in mining areas. Earlier emphasis on “engineering restoration” had given way to a more holistic approach known as “system ecological restoration”. There was a transition from solely addressing fragmented and isolated areas to considering the restoration of the entire regional ecosystem. Additionally, research on the carbon source/sink in mining areas and the carbon cycle mechanisms of the regional environment is progressing. The application of big data technologies, such as remote sensing, played a significant role in advancing monitoring and evaluation systems for mining rehabilitation. The effectiveness of restoration efforts in degraded mining areas was influenced by various factors including improvements in laws and regulations, system control systems, multi-disciplinary integration, and striking a balance between production and living ecology. Conclusion This study clarifies the current dilemmas and challenges in the research and application of damaged ecosystem restoration and carbon sequestration potential in mining areas and provides reference for future ecological restoration management and monitoring and evaluation in mining areas.
Pathogenicity of Ophiostomatoid Fungi associated with Ips subelongatus
LIU Ya, ZHOU Qin-zheng, WANG Hui-min, WANG Zheng, LU Quan
, Available online  , doi: 10.12403/j.1001-1498.20230201
: Objective The paper aims to investigate the harm degree and the potential risk of the ophiostomatoid fungi associated with Ips subelongatus by analyzing their pathogenicity. Method Through the artificial inoculation, 12 species of ophiostomatoid fungi isolated from the body and tunnel of I. subelongatus were inoculated on Larix olgensis. After 60 days, the lesion sizes were observed and measured, and the host resistance responses were tested by inoculation of Endoconidiophora fujiensis and Endoconidiophora laricicola on larch. Result The results showed that the area of lesions caused by E. laricicola, E. fujiensis, Ophiostoma hongxingense, Ophiostoma peniculi and Ophiostoma xinganense were larger than those of the control. The lesion areas produced by the other seven species of Ophiostoma showed no significant difference comparing with the control. The average lesion area produced by E. laricicola were the largest with 3.51 ± 0.18 cm2, and the content of terpenoids in the host showed a trend of first increasing and then decreasing, showing a strong pathogenicity. However, the average lesion area of E. fujiensis was 1.70 ± 0.08 cm2, and the content of host terpenoids showed a decreasing trend, exhibiting weak pathogenicity. Conclusion E. laricicola is highly pathogenic to larch, E. fujiensis, O. hongxingense, O. peniculi and O. xinganense are weakly pathogenic, while the other seven Ophiostoma fungi show no obvious pathogenicity.
Functional Conservation Existed in PagKNAT2/6a and PagKNAT2/6b During Xylem Development
Li Hai-yang, Zhao Li-zi, Zhao Yan-qiu
, Available online  , doi: 10.12403/j.1001-1498.20230244
: Objective To analyze the regulatory mechanism of PagKNAT2/6a in poplar dendritic development and the functional conservation of PagKNAT2/6a and PagKNAT2/6b in xylem development. Methods Gene sequence alignment analysis was carried out by using related software; Gene expression pattern analysis was performed by experiments such as GUS staining and real-time quantitative (qRT-PCR) of transgenic plants, and then stem anatomy analysis was also performed; Finally, genes related to secondary wall synthesis (such as cellulose synthesis-related genes CESA4, CESA7A, CESA7B, etc.; Hemicellulose synthesis-related genes GUX1a, GUX1b, PARVUS; Expression analysis and regulatory mechanism of lignin synthesis-related genes COMT, CAD, LAC4, etc) were explored. Results The sequences of PagKNAT2/6a and PagKNAT2/6b were highly similar, and they were expressed in different tissues of ‘84K’, showing higher expression levels in poplar stems, stem tips and young leaves. Stem anatomy analysis of transgenic plants abnormally expressing PagKNAT2/6a showed that PagKNAT2/6a overexpression inhibited xylem development compared with wild type. At the same time, qRT-PCR analysis showed that PagKNAT2/6a gene related the expression of genes related to secondary wall synthesis and affected xylem development. Conclusion PagKNAT2/6a and PagKNAT2/6b both negatively regulate xylem development and have functional conservation.
​Analysis and Prediction of Eucalyptus urophylla × E. grandis in Response to Thinning and Pruning
ZHANG Shi-tao, OUYANG Lin-nan, CHEN Shao-xiong, YANG Jia-qi
, Available online  , doi: 10.12403/j.1001-1498.20230161
Objective To explore the effects of thinning and pruning with different intensities on the growth of Eucalyptus urophylla × E. grandis, the BP neural network model was developed to predict the growth of E. urophylla × E. grandis under thinning and pruning treatment, for providing theoretical guidance for efficient management technology of E. urophylla × E. grandis. Method Taking 20%, 40% and 60% thinning and 38.18%, 42.39% and 48.18% Based on the E. urophylla × E. grandis in the Southern National Forest Seedling Demonstration Base with treatments of 20%, 40% and 60% thinning and 38.18%, 42.39% and 48.18% pruning, the stand growth indexes were investigated for 7 years after treatment, and the effects of different thinning and pruning treatments on the growth increment of the stands were analyzed. Furthermore, BP neural network was used to predict the response of cumulative increment to thinning and pruning. Root-mean-square error, Kappa and Pearson correlation coefficient were used to compare the prediction effect of models, and the optimal model was determined. Results Thinning treatment promoted the growth of DBH, crown width and tree volume, but did not promote the growth of height and wood production. The increment of DBH and tree volume was the highest in the stands with 60% thinning intensity, the increment of crown width was the highest in the stands with 20% thinning intensity, and the increment of height was the highest in the control stands. Pruning promoted the growth of DBH, but did not promote the growth of height and wood production. DBH increase was the highest in the stands with 38.18% pruning intensity. The treatment with 60% thinning and 48.18% pruning was conducive to the growth of E. urophylla × E. grandis. Both thinning and pruning could promote the right-sided distribution of diameter class, but the effect of pruning was not significant. In summary, the BP neural network model with 4 nodes in the hidden layer had the lowest root-mean-square error and the highest Kappa value and r value. Conclusion Thinning and pruning can significantly promote the growth of E. urophylla × E. grandis and the right-sided distribution of diameter class. The combination of high-intensity thinning and pruning is more beneficial to the growth of E. urophylla × E. grandis plantation and the cultivation of large diameter wood. The reasonable BP neural network model can accurately predict the promotion effect of thinning and pruning on stand growth and is an excellent model for predicting stand growth.
Effect of Endophytic Bacteria on Seedling Growth of Falcataria falcata
LIN Qian-xi, ZHENG Hui-quan, LU Guo-hui, HUANG Rong, WEI Ru-ping, WANG Run-hui, YAN Shu
, Available online  , doi: 10.12403/j.1001-1498.20230271
Objective To reveal the composition of dominant nodule endophytes in Falcataria falcata and explore their effect on the growth of Falcataria falcata seedlings, thus providing information for the development of Falcataria falcata fertilizer. Methods Endophytic bacteria were screened from Falcataria falcata nodules collected from three locations (Guangzhou, Huizhou and Maoming of Guangdong province), and inoculation with the three different geographical nodule endophytes (YZ, YD and YX) were conducted. The growth traits of Falcataria falcata seedlings after inoculation with different geographical endophytic bacteria were measured. Furthermore, species identification of endophytic bacteria with different treatments was performed by using 16S rRNA gene sequencing technology. Results Compared with the CK (negative control), Falcataria falcata seedlings under the three treatments were able to develop nodules successfully, and the seedling growth and nodule number, biomass, photosynthesis and nitrogen fixation ability were significantly higher than those under the control treatment. Particularly, the seedling height, root length, SPAD in the three treatments increased by 53.74%~95.65%, 52.91%~98.41%, 74.04%~86.18%, and 7.6~15.9 times compared to the control, respectively. Among the three inoculation treatments, seedling after inoculation with YZ showed the highest values of seedling growth, nodulation number and nitrogen fixation. Significant differences in the composition of endophytic bacteria were found among the three treatments, and YZ treatment had the largest number of OTU number and the highest diversity of α (Shannon index). The denitrifying Fe-II oxidizing bacterium had significant effects on seedlings height, nodules number, nitrogen concentration, nitrogen content and nitrogen fixation in Falcataria falcata. Conclusion The endophytes isolated from Falcataria falcata nodule can promote seedling growth, biomass accumulation, photosynthesis ability and nitrogen fixation in Falcataria falcata seedlings. Different geographical nodule endophytes show different composition of endophytic bacteria and varying effects on seedling growth. Endophytes with high diversity have obvious growth-promoting effect on Falcataria falcata seedlings.
Effect of UAV-LiDAR Point Density on Estimation Accuracy of Forest Inventory Attributes
ZHOU Mei, LI Chun-gan, LI Zhen, YU zhu
, Available online  , doi: 10.12403/j.1001-1498.20230242
: Objective Point density is a key factor affecting the cost and efficiency of data acquisition and pre-processing of unmanned aerial vehicle (UAV)-based light detection and ranging (LiDAR), and it is helpful to explore the effects of point density on the estimation accuracy of UAV-LiDAR-based forest inventory attributes to optimize the technical schemes for UAV-LiDAR forest applications. Methods This study focused on the planted Masson pine and Eucalyptus forests. The original UAV-LiDAR point cloud with a density of 247 points∙m−2 was reduced by 40%, 20%, 8%, 4%, and 2% according to the percentage of the total point reduction algorithm to obtain six plot-level UAV-LiDAR datasets, including five sets of reduced point densities. Each dataset was pre-processed separately, including point cloud classification, ground filtering, digital elevation model (DEM) generation, point cloud height normalization, and UAV-LiDAR-derived metric extractions. The same multiplicative power formula was used for estimating the same forest parameters (stand volume, basal area, mean height, and average diameter at breast height) for the same forest type, and each dataset was used to calibrate the model. Then, the differences in the goodness-of-fit statistics of the models were compared and analyzed based oncoefficient of determination (R2), relative root square error (rRMSE), mean prediction error (MPE), and the differences in the mean of the estimates and the UAV-LiDAR-derived metrics between the reduced point density datasets and the original point density dataset were statistically analyzed. Results The results indicated that the model accuracy remained essentially the same when the original point density was reduced to 100, 50,..., 5 points∙m−2, and there were no statistically significant differences (p≥0.05) in the estimates of forest inventory attributes between the reduced point density datasets and the original point density dataset. There were basically no statistically significant differences (p≥0.05) in UAV-LiDAR-derived metrics between the reduced point density datasets and the original point density dataset. Conclusion In the application of UAV lidar forest resource survey and monitoring, the point cloud density can be as low as 5 points∙m−2. However, the results of this experiment still need to be verified by acquiring point cloud data at different densities at different flight altitudes.
Effect of Desiccation on Germination of Larix kaempferi Embryoids
SUN Hai-tao, YANG Ling, QI Li-wang, LI Wan-feng
, Available online  , doi: 10.12403/j.1001-1498.20230311
Objective To improve the germination ability of Larix kaempferi embryoids and optimize the breeding technology of Larix kaempferi. Method In this study, we conducted classification on embryoids based on the number of cotyledon and the hypocotyl shape. Subsequently, their germination rates were recorded respectively. The germination rate of type Ⅰ embryoids was evaluated after desiccation using “paper vessel method”. Result Type I embryoids exhibited an initial germination rate of 5%, while the remaining types did not show any germination. However, after drying for two weeks, the germination rate of type I embryoids significantly increased to 69.43%, and embryoids with desiccation response were more likely to germinate. Conclusion These results show that the germination rate of Larix kaempferi embryoids is significantly improved after desiccation, which provides insights into new strategies for improving seedling production for this species.
Thermal stress photosynthetic response of Picea pungens
OUYANG Fang-qun, CUI Xia, ZHANG Hui, DENG Jun-yu, SHI Qing-song, LI Yu-ling, SUN Meng
, Available online  , doi: 10.12403/j.1001-1498.20230223
Objective The continuous global warming will be detrimental to the growth of Picea pungens. Studying the growth and photosynthetic response mechanism under high temperature stress would provide a reference for the introduction and cultivation of P. pungens. Methods Three temperatures were set at 45, 50 and 55 ℃, and treated for 6 hours using P. pungens seedlings. Among them, three different durations of 12,18 and 24 hours were also set under 45 ℃ treatment, and room temperature was used as a control. The growth phenotype, relative water content and chlorophyll fluorescence parameters of P. pungens seedlings after treatment, 7 and 28 days of recovery were studied, and the effects of high temperature and stress duration on the growth and photosynthesis of P. pungens were analyzed. Result The growth of P. pungens could basically be restored after 6 hours treatment at 45 ℃, while those treated at 50 and 55 ℃, their needles turned yellow, withers and falls, accompanied by the decrease of relative water content. The fluorescence parameters photochemical efficiency for photosystem I (Y(I)), relative electron transfer rate of photosystem I (ETR(I)), non-photochemical energy dissipation due to donor-side restriction (Y(ND)), non-photochemical energy dissipation due to receptor-side restriction (Y(NA)), photochemical efficiency for photosystem II (Y(II)), the relative electron transfer rate of photosystem II (ETR(II)), PSII maximum light energy conversion efficiency (Fv/Fm) and the maximum quantum yield of electron transport between PSII and PSI (φEO) were significantly lower than those treated and controlled at 45 ℃. Although the phenotypic change could not be seen after treatment at 45 ℃ for 6, 12, 18 and 24 hours, it was found that the needles continued to lose water and turn yellow at 12 hours and 18 hours during the recovery period, and the whole needles turned yellow after 24 hours treatment, basically dried up and fell off, and the relative water content of the needles was the lowest. When recovering for 28 days, φEo at 18 and 24 hours was almost 0. Conclusion P. pungens can withstand high temperature treatment at 45 ℃ for 6 h, but it is not resistant to high temperature of 50 ℃ and 55 ℃. The seedlings with a high temperature treatment time of 45 ℃ for more than 12 hours will suffer severe water loss and dry needles, which will have a significant impact on the photosynthetic characteristics and make it difficult to resume normal growth.
The Physiological Response of Populus alba to Drought Stress
XU Hui, XUE Yuan
, Available online  , doi: 10.12403/j.1001-1498.20230472
Objective In this study, Populus alba was used to detect the effect of drought stress on growth and development, which provided reference for the molecular mechanism of the response to drought stress in woody. Method The seedlings of Populus alba about five weeks were treated with drought stress, the growth state and drought stress-related physiological indicators and genes were record and detected to reveal the resistance of Populus alba to drought stress. Result The results showed that the water content of leaves decreased significantly and stomatal aperture became smaller after 8 days of drought treatment; meanwhile ROS increased significantly, ABA accumulated in the body, and the growth-related hormone IAA content decreased, drought stress-related genes were upregulated. Conclusion By detecting the tolerance of Populus alba to drought stress from multiple perspective, the growth of their seedlings is significantly inhibited after drought treatment for 8 days, which indicates that watering timely is necessary.
Cloning and Yeast Expression Function Identification of High Expression XsKCS7 Gene in Xanthoceras sorbifolium Seed
LIANG Chong-jun, LI Lin-kun, HU Zhen-hua, ZHANG Wei, XU Hui-hui, WANG Li-bing
, Available online  , doi: 10.12403/j.1001-1498.20230338
: Objective : To explore the key genes of regulating nervonic acid biosynthesis in Xanthoceras sorbifolium seeds. Method : This study analyzed the expression pattern of the 3-ketoesteryl-CoA synthase (3-ketoacyl-CoA synthase, KCS) gene family in seeds at different developmental periods according to the combined transcriptome of the reference genome. Gene XsKCS7 was cloned by RT-PCR, and was analyzed by Bioinformatics analysis of XsKCS7 protein. And the XsKCS7 gene was transformed into Saccharomyces cerevisiae to identify the gene function. Result : The expression level of XsKCS7 gene in seeds of X. sorbifolium was much higher than other KCS genes. The open reading frame of XsKCS7 was 1,512 bp, encoding 503 amino acids, havd three typical conserved domains of KCS family "GMGCSA", "FGNTSSSS" and "GSGFKCNSAVW", and a close relationship with the homologous gene of Hevea brasiliensis,at 67.62%. XsKCS7 heterologous transformation of Saccharomyces cerevisiae regulated the synthesis of erucic acid and nervonic acid. Conclusion : XsKCS7 gene is a key gene that regulates the synthesis of erucic acid and nervonic acid in seeds of X. sorbifolium.
Optimization and Application of Transient Transformation System of Larix kaempferi
XING Jun-xia, ZANG Qiao-Lu, YE Zha-long, ZHANG Chen-yi, CHENG Dong-xia, QI Li-wang, YANG Ling, LI Wan-feng
, Available online  , doi: 10.12403/j.1001-1498.20230390
Objective To optimize an Agrobacterium-mediated transient transformation system with Larix kaempferi embryogenic callus. Methods The embryogenic callus of Larix kaempferi cultured in liquid medium for 7 days was used as the receptor material, and pCAMBIA1305.1 vector carrying β-glucuronidase (GUS) was used for transient transformation. Based on the expression level and enzyme activity of GUS, the optimal infection solution concentration, infection time and co-culture time were screened. The activity of Larix kaempferi scarecrow-like 6 (LaSCL6) promoter was analyzed with the screened transformation system. Results After transient transformation, the expression of GUS was obvious. When the concentration of infection solution was 0.2, the infection lasted for 5 minutes, and the co-culture time was 72 hours, GUS expression was the highest, with -2.274 2. When the concentration of infection solution was 0.05, the infection lasted for 5 minutes, and the co-culture time was 72 hours, GUS enzyme activity was the highest with 25.728 6 U/L. The activity of LaSCL6 promoter was 1.55 times higher than that of CaMV35S promoter Conclusion In view of the expression level and enzyme activity of GUS, transformation efficiency is high when the concentration of infection solution is 0.05, the infection time is 5 minutes, and the co-culture time is 24 hours, which can be used for efficient transformation of embryogenic callus of Larix kaempferi.
Comparison of Morphological and Biological Characteristics of Two Bamboo Insects Adults in the Same Area
FENG Jia-de, WANG mei, FENG Dan, FENG Zhi-wei, WEN yi-fu, CHEN Peng
, Available online  , doi: 10.12403/j.1001-1498.20230186
Objective To compare the similarities and differences between the morphology and biology of two insects of the genus Bamboo, Ceracris kiangsu Tsai and Ceracris nigricornis Walker. Method The adults of two kinds of bamboo locust collected from the same geographical area were reared in a greenhouse, and their morphological characteristics: body length, antennae, hind femur, head width, external genitalia, etc., and living habits: activity rules, mating habits. The feeding habits of host plants were observed, recorded and statistically analyzed. Result The results showed that the body length of the female adult C. kiangsu was 36.55 ± 1.42mm, the antennae was 23.46 ± 1.29mm, the hind femur was 21.68 ± 0.28mm, and the head width was 5.33 ± 0.2mm; the body length of the male adults was 31.35 ± 0.75mm, the antennae was 23.22 ± 0.9mm, the hind femur was 17.86 ± 0.23mm,and the head width was 4.08 ± 0.19mm. The body length of the female adult of C. nigricornis was34.63 ± 0.44mm, the antennae was 18.34 ± 0.56mm, the hind femur was 18.67 ± 1.62mm, and the head width was 4.61 ± 0.18mm; the body length of the male adult was 26.82 ± 2.77mm, the antennae was 17.75 ± 1.58mm, the hind femur was 16.09 ± 0.47mm, the head width was 3.5 ± 0.29mm. There were significant differences in body length between male and female adults of the same species of bamboo insects. There were significant differences in body length, antennae, hind femur, and head width between the two types of bamboo insects. The peak mating period of the C.s kiangsu was 14-17 o'clock, and the peak mating period of the C. nigricornis was 9-12 o'clock. Two kinds of bamboo locust adults showed the same feeding preference when faced with three different host plants, and they all preferred to eat bamboo (Phyllostachys edulis), followed by plantain (Musa basjoo), and finally brome (Bromus inermis), but the C. nigricornis consumed more food than the C.kiangsu. Conclusion The similarity and difference in morphology and biological learning of the two kinds of bamboo locusts are the basis for the sympatric occurrence of the two kinds of bamboo locusts, which provides some basic information support for the monitoring and control of the two kinds of bamboo locusts.
Effects of Different Thinning Retention Densities on Branch Growth of Chinese Fir Plantations
WANG Jia-qi, MA Dong-xu, CHEN Kuai-ming, LAN Wei-li, LIN Kai-min
, Available online  , doi: 10.12403/j.1001-1498.20230334
Objective To study the effects of different thinning retention densities on the branch growth of Chinese fir plantations, and to provide scientific theoretical basis and technical support for directed cultivation of Chinese fir knotless-wood. Method Based on the 9-year-old Chinese fir plantations in Guanzhuang state-owned forest farm, Shaxian County, Fujian province, three kinds of thinning retention densities (1200 trees·hm−2(thinning intensity: 67% , L) , 1800 trees·hm−2(thinning intensity: 51% , M) and 2250 trees·hm−2(thinning intensity: 27% , H) were set up. In the fifth year after thinning, standard trees were selected in different plots to study the effect of thinning treatments on the branch growth of Chinese fir. Result 1)The total number of branches, the number of branches below 8 m, the number of branches above 8 m, the number of dead branches, the number of living branches all under L treatment were the largest, followed by treatment M and H, and the percentage of dead branches under treatment H were the largest, followed by treatment M and L. 2)The basal diameter increased with the decrease of thinning intensity which showed L > m > H, and there was significant difference between L and H (P < 0.05) , which indicated that the lower retention density was more conducive to the branch growth. 3)There was a significant linear correlation between the basal diameter and the length of the living branch, while correlation between the basal diameter and the length of the dead branch was small. 4)The basal diameter, branch length, the number of dead branches and the number of living branches increased with the increase of vertical height, while the basal diameter and the length of living branches and the branching angle of H and M decreased with the increase of vertical height of the trunk. 5)The basal diameter, branch length and branching angle of dead and living branches were larger in the southern region (90~225 °) than in the northern region, but the number of branches was larger in the eastern region (0~180 °) than in the western region. Conclusion The thinning intensity should be adjusted according to different cultivation purposes. The lower retention density can inhibit the growth of basal diameter and number of branches, thus reducing the size and number of knots and improving the wood quality. In this study, the retention density1800 trees/ha is more suitable to cultivate knotless large-diameter timber.
Investigation and Analysis on Host Species and Their Resistance Substances to Bacterial Bark Canker of Populus × euramericana
LI Yong, CHANG Ju-pu, GUO Li-min, SUN Shang, YANG Xu-qi, PIAO Chun-gen
, Available online  
Objective To investigate and analyze the host species of bacterial canker of Populus × euramericana, the disease-resistant varieties and the possible disease-resistant substances they contain. Method The host of the pathogen and the resistant varieties were determined by field investigation and inoculation tests. The content of active substances in the bark of disease-resistant and susceptible varieties was analyzed by HPLC. Result The hosts of bacterial pathogen of P. × euramericana canker are P. deltoides, P. × euramericana and Salix matsudana. P. × euramericana cl. 'Zhonglin 46', P. deltoides cl. '2025', P. × euramericana cv. '2001', P. deltoides cl '313', P. deltoides 'Zhonghe-1' and P. deltoides '16-09' were highly susceptible to the bark canker disease; P. × euramericana 'Yukang 1' and P. deltoides '16-10' were highly resistant varieties, P. deltoides '131', P. deltoides '03-59', P. deltoides '02-212' and P. deltoides '03-34' were resistant varieties. Hybrid willows and Salix babylonica are resistant to the pathogen, and Salix × aureo-pendula can be affected, but do not cause serious disease. The HPLC analysis showed that the contents of catechol, benzoic acid and chlorogenic acid in the bark of resistant and highly susceptible poplar varieties were significantly different. The catechol and catechin increased when the hosts were infected by Lonsdalea populi. Conclusion In this study, the host species of bacterial canker of P. × euramericana are determined, and resistant and highly susceptible poplar varieties are screened. It is showed the catechol and catechin are important compound for host to defense the pathogen infection. The results will be helpful to the control of the bacterial disease of poplar.
Effects of Castanopsis kawakamii Forest Litter on Seed Germination of Pinus massoniana
JIA Mei-hua, WANG Zhe, LIU Jin-fu, JIN Meng-ran, HE Zhong-sheng, XING Cong, SHI You-wen, SHEN Cai-xia
, Available online  
Objective To understand the effect of litter of Castanopsis kawakamii natural forest on the competitive intensity of regeneration of Pinus massoniana. Method The allelopathic effects of litter extract of natural forest with different concentration and decomposition degree on seed germination and radicle growth of P. massoniana were studied. Result (1) The main factor affecting the germination of P. massoniana seeds was the degree of litter decomposition. Compared with the blank control, the litter of undecomposed layer and fully decomposed layer had no significant effect on the germination of P. massoniana seeds; the semi-decomposed layer inhibited the germination rate and germination index and promoted the germination potential. (2) The main factors affecting the growth of radicle were the concentration and action time of litter extract, and the effect of undecomposed layer on the whole radicle growth period of P. massoniana seeds was enhanced with the decrease of concentration, but increased with the decrease of concentration, and the promoting effect was the strongest at the concentration of 1 ≤ 100, and the effect of semi-decomposition layer was promoted by low concentration and high concentration, and the intermediate concentration was inhibited by the undecomposed layer. The fully decomposition layer showed promoting effect as a whole, and the promoting effect decreased with the decrease of concentration. (3) Correspondence analysis showed that different decomposition degree-concentration had no significant effect on seed germination of P. massoniana, but had significant correlation with radicle growth. Conclusion The result proves that the litter extract of different decomposition degree has a weak promoting or inhibiting effect on the seed germination of P. massoniana, promotes the growth of radicle at low concentration, and promotes the regeneration of P. massoniana, which will intensify the interspecific competition in the forest, and lead to the inhibition of the natural regeneration of C. kawakamii.