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Hydrological Effects of Litters in Different Types of Cunninghamia lanceolata Plantations in Huitong of Hunan, China
ZHANG Ying, XU Qing, Gao De-qiang, SUI Ming-zhen, ZHANG Bei-bei, REN Ran-ran1,ZUO Hai-jun, WANG Si-long
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Abstract:
Objective To evaluate the impact of litter on hydrology in different types of Cunninghamia lanceolata plantations, and provide references for the management of understory and the assessment of ecosystem services. Method Based on field investigation and immersion experiments, the authors examined the storage capacity, water retention characteristics, and effective interception capacity of the litters collected from pure Cunninghamia lanceolata forest (PC), mixed forest of Cunninghamia lanceolata and Cinnamomum camphora (MCC) and mixed forest of Cunninghamia lanceolata and Alnus cremastogyne (MCA) in subtropical China. Result (1) The litter storage of different types of Cunninghamia lanceolata plantation varied from 7.94 to 8.88 t·hm−2, with an order of MCC > MCA > PC, and the proportion of semi-decomposed litters was greater than that of undecomposed litters. (2) The water-absorption rate of litter in various plantations increased rapidly within the initial 4 hours of immersion, followed by a slower increase at 4−10 hours of immersion, and finally saturated. Compared with semi-decomposed litter, the undecomposed litter had a higher maximum water-holding capacity and maximum water-holding capacity. Both semi-decomposed and undecomposed litters in mixed plantations exhibited higher maximum water-holding rate and maximum water holding capacity than that in pure Cunninghamia lanceolata plantation. (3) The maximum interception rate of the three types of plantation ranged from 152.33% to 229.55%. The maximum and effective interception capacity were 12.62−17.94 t·hm−2 and 10.26−14.75 t·hm−2, respectively, exhibiting higher in both MCC and MCA than in PC (P < 0.05). Conclusion The hydrological effect of litters varies among different types of Cunninghamia lanceolata plantation in Huitong, while the hydrological characteristics of mixed forests of Cunninghamia lanceolata with broad-leaved species are significantly better than that of pure Cunninghamia lanceolata plantation. Therefore, mixed stand of Cunninghamia lanceolata with broad-leaved species should be recommended in forest management and vegetation restoration.
Spatiotemporal Expression Analysis of PaAG2 Gene in Populus alba × P. glandulosa '84K'
ZHONG Shan-chen, WU Shu, WANG Li, SU Xiao-hua, ZHANG Bing-yu
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Abstract:
Objective To identify the role of PtAG2 gene in the development of male flowers of poplar. Method Based on the regulation of AG genes (PtAG1 and PtAG2) in the stamens and carpels of monoecious plants, the spatial and temporal specificity of PaAG2 gene of Populus alba × P. glandulosa '84K' was studied by means of paraffin section, real-time quantitative PCR and in situ hybridization. Taking the flower branches of P. alba × P. glandulosa '84K' as test materials, the inflorescences were continuously sampled within one week after hydroponic culture to observe the development of male flowers by paraffin sectioned technique. Real-time quantitative PCR was used to detect the expression of PaAG2 in the roots, stems, leaves and inflorescence of P. alba × P. glandulosa '84K'. In situ hybridization was used to detect the specific expression sites of PaAG2 in the flower organs of P. alba × P. glandulosa '84K' male flowers, so the expression pattern of PaAG2 gene was analyzed. Result During the development of male flowers of P. alba × P. glandulosa '84K', the anthers matured gradually. At the same time, the expression of PaAG2 increased at initial and then decreased, and the transcription was also be detected in the roots, stems and leaves of tissue cultured P. alba × P. glandulosa '84K'. The results of in situ hybridization showed that PaAG2 was expressed in the anthers of P. alba × P. glandulosa '84K' male flowers but not in the surrounding tissues. Conclusion PaAG2 gene is closely related to the male flower development of P. alba × P. glandulosa '84K', so it is expected to be a target gene for genetic engineering to improve poplar pollen. However, whether the PaAG2 gene participates in the regulation of the growth and development of other tissues of poplar needs to be further studied.
Construction of Core Collection of Catalpa fargesii Bur. Based on Phenotype
YU Xiao-chi, LI Feng, OU Yang, ZHANG Peng, GUO Xiao-long, XIAO Yao, ZHAO Qiu-ling, YANG Gui-juan, WANG Jun-hui, MA Wen-jun
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Abstract:
Objective To obtain a more reliable primary core germplasm group of Catalpa fargesii, to strengthen the breeding, development and utilization and molecular genetics research, to reduce the conservation cost of germplasm resources, and to promote the identification and effective utilization of C. fargesii germplasm resources. Method Based on the leaf traits, the growth traits and the wood traits of 200 C. fargesii clones from Gansu, Shaanxi, Shanxi and He'nan provinces, five genetic distance calculation methods, six clustering methods, three sampling methods and five sampling ratios were used to construct the primary core germplasm resources, and then evaluated them. Result Using the Euclidean distance and the Single system clustering method, the deviation sampling with 15% sampling proportion was adopt to construct the primary core collection of 30 clones, the mean difference percentage was 10%, the variance difference percentage was 40%, the coincidence rate of range was 91.95%, and the changeable rate of coefficient of variation was 136.96%, which could best represent the original germplasm group. The construction of core collection increased the percentage of germplasm with leaf length, leaf width, leaf length width ratio, petiole length, diameter at breast height, crown width and elastic modulus higher than the average, and reduced the percentage of germplasm with Pilodyn value higher than the average. The percentage of core collection in Shaanxi, Shanxi and He'nan provinces were higher than that of the original collection. Conclusion This research showed that there are abundant genetic variation in each trait of C. fargesii clones. The 30 core germplasms not only retain the mean, range and degree of variation of the original germplasms, but also increase the variationcoefficient of the germplasms, and slightly increase the growth and the material quality level of the germplasms. This research laid a foundation for promoting the identification and effective utilization of germplasm resources.
Electroantennogram and Behavioral Responses of Dioryctria abietella to Volatiles from Picea likiangensis var. linzhiensis Cones
TANG Xiao-qin, WANG Si-zhan, LU Jie, GAO Tan, CHEN Yi-qu
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Objective To screen the cone volatiles in the cones of Picea likiangensis var. linzhiensis, which have an attractive effect on the Dioryctria abietella, in order to clarify the host selection mechanism of D. abietella and provide a theoretical basis for the pest-free control of pests. Method Electroantennography (EAG) and "Y" olfactometer were used to measure the EAG reaction and olfactory behavior of D. abietella to the main components of the cone volatiles of P. likiangensis var. linzhiensis with different concentrations and formulations. Result The results of GC-MS showed that the healthy new cones and the infested old cones contained six compounds, but the composition and content were slightly different. The results of EAG showed that in the range of 10 μg/μl, the higher the concentration of α-pinene, β-pinene, (1S)-(-)-β-pinene, limonene, the bigger the EAG response of the D. abietella in different states. However, the EAG value decreased after 10 μg/μl. Under the concentration of 10 μg/μl, the EAG value of the moth in different states was significantly higher than under the other concentrations (P < 0.05). The EAG reaction of unmated female and male moths on beta-caryophyllene increased with the concentration, and the EAG reaction value in 0.5 μg/μl was not significantly different from the control (P > 0.05). After reaching 1 μg/μl, no significant difference was found in the EAG value among concentrations (P > 0.05), while the EAG reaction between 0.5 μg/μl and 1 μg/μl was significantly different (P < 0.05). The EAG response of the mated female moth and the unmated female moth to myrcene increased with the concentration. When the concentration reached 100 μg/μl, the EAG value was the largest, nevertheless the EAG value of 100 μg/μl and 10 μg/μl was not significantly different (P > 0.05). The results of olfactory behavior showed that formula A2, A3, A5, A7 and A8 had obvious attracting effect, especially formula A7, and the attracting rate of D. abietella in different states was over 70%. Unfortunately, formula A4, A9, A10 had obvious avoidance effect, and the avoidance rate of D. abietella in different states was as high as 50%~70%. Conclusion 10 μg/μl of each component is the best stimulation concentration. Beta-caryophyllene has obvious attracting effect, while myrcene has obvious avoidance effect.
Cloning and Transient Expression Analysis of CUC1 Gene from Fraxinus mandshurica Rupr.
CUI Jing-hong, YU Lei, LIANG Nan-song, SONG Ting-ting, LYU Yi-pin, JI Xin-tong, XU Liang, ZHAO Fu-jiang, ZHAN Ya-guang
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Abstract:
Objective To clone the CUC1 gene of Fraxinus mandshurica and analyze its expression characteristics, so as to lay a foundation for the regulation of the gene in the regeneration of F. mandshurica Method The FmCUC1 gene was cloned from F. mandshurica seedlings. The nucleotide sequence of FmCUC1 gene and the amino acid sequence of its coding protein were analyzed by bioinformatics software, and the phylogenetic tree was constructed. The FmCUC1 gene was transferred into onion inner epidermis cells by Agrobacterium tumefaciens infection method for subcellular localization. The tissue surface of FmCUC1 gene in root, stem, leaf and apical bud was analyzed by real-time fluorescence quantitative analysis. At the same time, the seedlings of F. mandshurica were sprayed with IAA, 6-BA and BR hormones to analyze the expression pattern of FmCUC1 gene induced by different hormone signals; the FmCUC1 gene was transiently transformed into F. mandshurica by A. tumefaciens for 72 hours. Result The full length of FmCUC1 gene was 807 bp, encoding 269 amino acids. FmCUC1 was a stable hydrophobic protein with a conserved NAC domain protein domain. The sequence similarity of FmCUC1 protein and Olea europaea subsp. europaea protein was 86.17%, which was close to each other. FmCUC1 protein was located in the nucleus. q-RT PCR analysis showed that the expression of FmCUC1 gene was the highest in the terminal bud of F. mandshurica; during hypocotyl bud regeneration, the expression of FmCUC1 gene was high in both bud point formation and clump formation; during seed germination, the expression of FmCUC1 gene reached two peaks on the 4th and 8th day, which were 8.56 and 8.46 times of that on the first day, respectively. The results of exogenous spraying IAA, 6-BA and BR showed that the expression of FmCUC1 gene was up-regulated compared with the control, and reached the highest value after 72 h of IAA and BR treatment, which were 45.72 times and 20.36 times of the control, respectively, and reached the peak value after 48 h of 6-BA treatment, which was 59.40 times of the control. A. tumefaciens mediated transient overexpression of FmCUC1 gene for 72 hours, the expression of FmCUC1 gene and its downstream STM gene increased significantly. Conclusion FmCUC1 gene belongs to NAC family and is a nuclear transcription factor. It participates in the process of shoot regeneration of Salix mandshurica, and responds to the induction of IAA, 6-BA and BR plant hormone signals. Overexpression of FmCUC1 gene can activate the expression of its downstream STM gene, which is conducive to the formation of apical meristem.
Response of Individual Height of Larix principis-rupprechtii Plantation to Site Factors and Stand Characteristics in Liupan Mountain Area
ZHANG Zhong-hui, WANG Yan-hui, GUO Jian-bin, WANG Xiao
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Abstract:
Objective For the main afforestation species of Larix principis-rupprechtii in the forest area of Liupan Mountains, To study the response of individual tree height in Larix principis-rupprechtii, the main afforestation species in the forest area of Liupan Mountain Area, to site conditions and stand structure, in order to predict tree height growth more accurately, and to determine the suitable site for afforestation and proper stand structure for forest management, so as to guide the accurate and precise management of stand structure. Method The tree height growth data of L. principis-rupprechtii were obtained by carrying out the survey of analytic trees of various dominances in selected typical plots with various site conditions and stand structure characters, and the response law and suitable function forms of tree height response to all single factors were determined by the upper boundary line method. Then the tree height growth model which can reflect the influence of multiple factors was formed by a continuous multiplication. The model parameters were fitted using the measured data for getting the optimal tree height growth model. Result (1) The growth process of individual tree height of L. principis-rupprechtii showed a "S" curve. (2) Correlation analysis showed that the influence on tree height growth by the factors except tree age followed the order of elevation > canopy density > tree dominance > stand density > slope aspect > slope. (3) The most suitable conditions for the height growth of L. principis-rupprechtii are the elevation range of 2 000−2 400 m, the slope aspect range from shade slope to half shade slope, the slope gradient range of 20°−225°, the canopy density range of 0.49−20.64, the stand density of 1100−21300 trees/hm2. In addition, the height of individual trees increased with rising tree dominance but with a leveling-off increase rate after the dominance is higher than 0.2. (4) The height growth model of individual trees was established by coupling the response functions to the main influencing factors, with a satisfactory fitness. Conclusion The individual tree height growth of L. principis-rupprechtii is affected by both site conditions and stand structure characteristics. The main influencing factors are tree age, elevation, canopy density, and tree dominance. When considering the influencing factors, the coupled model of individual tree height growth can predict the spatio-temporal variation of individual tree height more accurately, and benefit the rational management of L. principis-rupprechtii plantation.
Prediction of Carbon, Nitrogen, and Phosphorus Contents of Chinese fir Based on Ecological Factors and Artificial Neural Networks
TONG Ran, CHEN Qing-biao, ZHOU Ben-zhi
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Abstract:
Objective To achieve the accurate, economical and quick prediction of leaf carbon, nitrogen, and phosphorus contents of Chinese fir. Method Taking the Chinese fir (Cunninghamia lanceolata) plantations in subtropical China as objects, a RBF (radial basis function) neural network with highly nonlinear mapping relationships between input layer and output layer was used to build the optimal prediction models for the leaf C, N, and P contents of Chinese fir and ecological factors including geography, climate and soil properties. Result The simulation prediction of leaf average C, N, and P contents were 476.68, 12.27, and 1.24 mg·g−1, respectively, the leaf N content of Chinese fir was far less than that of terrestrial plants in China; the leaf average C/N, C/P, and N/P were 40.28, 412.01, and 10.50, respectively. The prediction results were well consistent with the measured values, indicating that it was feasible to use the RBF neural network model for predicting the relationships between leaf C, N, and P contents and ecological factors. Conclusion These models could accurately estimate the leaf C, N, and P contents of Chinese fir, the mean errors are 1.82%, 9.88%, and 7.02%, respectively. Both the relatively low leaf N content and N/P indicate the growth of Chinese fir is limited by N element in subtropical China.
Radial Genetic Variation Analysis and Comprehensive Evaluation of Wood Properties in Ten-year-old Section Aigeiros Clones
YAN Han-wei, CHENG Ya-jing, YU Tong-tong, YU Na, ZHOU Liang, LIU Sheng-quan
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Objective The purpose of this research is to study the differences and genetic characteristics of various timber traits among Section Aigeiros clones, and to evaluate the excellent degree of wood properties of the clones, so as to provide theoretical basis for breeding clones with excellent comprehensive characters in experimental areas, and promote the directional cultivation of industrial timber. Method The wood properties (anatomical features, physical properties, and chemical composition) of ten-year-old sample trees (5 plants per clone) were measured from 8 experimental Section Aigeiros clones in Jiaozuo, He'nan Province. The genetic variation and genetic parameters of 18 wood traits were analyzed, and principal component analysis was used to evaluate the clones. Result Except the hemicellulose, the other 17 wood properties of poplar clones showed significant differences among clones. The variation range of clone repeatability was 0.49-0.93, in which the total dry density, basic density, total cellulose, cell diameter and cell cavity diameter were more than 0.8. The phenotypic variation of clones was greater than the genetic variation. Populus × euramericana `Zhonglin 46' was selected as the superior clones based on the highest core of principal component factors. Conclusion The eight poplar clones showed genetic differences in 18 wood properties, which were under strong genetic control and possessed the conditions of genetic improvement. There were radial differences in clone repeatability. With the increase of annual rings, the variation range of physical properties was the smallest, and the total dry density and basic density were relatively stable.
Genome-wide Identification, Characterization, and Expression Analysis of UGT Gene Family members in Sea buckthorn (Hippophae rhamnoides L.)
LYU Zhong-rui, LIU Hong, ZHANG Guo-yun, YU Li-yang, LUO Hong-mei, HE Cai-yun
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Objective To study the characteristics and potential functions of sea buckthorn (Hippophae rhamnoides) and to analyze the biosynthesis mechanism and accumulation pattern of flavonoid glycosides by identifying the UGT gene family members in sea buckthorn. Method BLASTP and hmmsearch were used to identify the members of the HrUGT gene family based on sea buckthorn genome database. The protein physical and chemical properties, phylogenesis, protein motif and gene structure and gene duplication were analyzed by using Prot-Param, MUSCLE, MAGA7.0, MEME and MCScanX. Result 89 HrUGTs containing the plant secondary product glycosyltransferase motif (PSPG) were identified from the sea buckthorn genome. The length of sea buckthorn UGT proteins ranged from 266 to 533 amino acids, the average molecular weight was 50.00 KDa, and the average isoelectric point was 5.89. According to the phylogenetic relationship, the 89 HrUGTs could be divided into 16 major groups. 84 HrUGTs were distributed on 11 chromosomes except chromosome 7. Tandem duplication was a predominant duplication event which caused the expansion of HrUGT genes. Transcriptomic data and RT-qPCR analysis indicated that most of UGT genes had a wide range of fruit development stage expression characteristics. Conclusion The complete information of the HrUGT gene family is obtained, which will benefit the study on the biological functions of HrUGTs.
Absorption and Transformation of Sulfur Dioxide by Populus × euramericana cv. 'Purui'
FENG Jin-xia, MA Jie, WAN Xian-chong
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Objective To investigate the absorption and transformation of sulfur dioxide in the air by three poplar varieties in order to study the mechanism of sulfur dioxide resistance and the capacity of Populus × euramericana cv. 'Purui' in purifying the atmosphere. Method Three poplar varieties (Populus × euramericana cv. 'Purui' (Purui), Populus × euramericana cv. '74/76' (107) and Populus × euramericana cl. 'Zhonglin 46' (Zhonglin 46)) were selected to compare their effects on absorbing and purifying the sulfur dioxide in atmosphere. The diurnal dynamic changes of sulfur dioxide concentration in the air inside and outside the forests were measured. The concentrations of sulfate (SO42-) in the leaves of Purui, Zhonglin 46 and 107 under different sulfur dioxide pollution environments were measured. Result The daily dynamic changes of sulfur dioxide concentration inside and outside the forests indicated that the three poplar varieties were able to absorb sulfur dioxide, and hence purify the air. Among them, Purui had significantly greater capacity in sulfur dioxide absorption and air purification than Zhonglin 46 and 107. Sulfate ion concentration in Purui leaves was significantly higher than that in Zhonglin 46 and 107. Whether in the environment of high or low concentration of sulfur dioxide, the sulfate ion in the leaves of Purui was higher than that of the other two varieties, indicating that Purui had stronger ability to absorb sulfur dioxide and convert it into non-toxic sulfur compounds. This is also an important mechanism of sulfur dioxide resistance for Purui. Conclusion Among the three poplar varieties, Purui has stronger ability to purify the atmosphere polluted by sulfur dioxide, thereby detoxifying sulfur dioxide, so as to better purify the air and reduce the harm of haze to human body. Compared with other poplar species, Purui has stronger ability to convert sulfur dioxide into non-toxic sulfate ions, which can facilitates its detoxification.
Variation and Selection of Seedling Growth Traits Among Juglans mandshurica Provenances and Families
LU Xian-bo, XU Lian-feng, PANG Zhong-yi, LIU Ji-feng, WEN Bao-yang, PEI Xiao-na, ZHAO Ling, WANG Xue-gang, ZHAO Xi-yang
, Available online  
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Objective To analyze and select the genetic variation of growth traits among provenances and families of Juglans mandshurica, in order to promote the selection and breeding of J. mandshurica superior varieties. Method In this study, the growth characteristics (tree height, annual growth of tree height, ground diameter, crown width, straightness, branch angle, number of side branches and taperingness) of 28 J. mandshurica families (6-years-old) within 4 provenances at Wanrenhuan Forest Farm were measured and analyzed. Result The results of analysis of variance showed that most of the traits reached extremely significant differences among various sources (P < 0.01). The phenotypic and genetic coefficient of variation of these traits ranged from 12.865% to 43.171% and from 5.176% to 25.533%, respectively. The family heritability and individual heritability were ranged from 0.284 to 0.797 and from 0.048 to 0.483, respectively. The results of correlation analysis showed that the correlation of almost all traits reached a significant level (P < 0.05), except the correlations between sharpness and branch angle, between sharpness and number of side branches, and between straightness and crown width. The results of general combining ability analysis showed that with a selection rate of 20%, 6 excellent parents were screened according to different traits. The results of principal component analysis (PCA) showed that the cumulative contribution rate of the three principal components reached 73.264%, indicating that the three principal components contained most information of the measured trait. According to the comprehensive scores of PCA, one excellent provenance, three excellent families and 10 excellent individual plants were initially selected. The realistic gains of tree height, average annual increase in tree height, ground diameter and crown width of selected provenance were 3.109%, 5.014%, 2.193%, and 1.040%, respectively. The genetic gains of the 4 traits of the families selected were 5.835%, 5.410%, 7.908%, and 6.069%, respectively. The genetic gains of the 4 traits of selected individuals were 26.74%, 24.11%, 23.91% and 26.53%, respectively. Conclusion The growth traits of J. mandshurica have rich variations within provenances and families. The excellent provenances, parents, families and individuals preliminary selected could lay a basis for the selection and application of J. mandshurica varieties.
Analysis on Spatial Variability of Soil Trace Elements in Miyaluo Subalpine Dark Coniferous Forest of Western Sichuan, China
XIONG Kai, ZHAO Yu-juan, CHEN Jian, ZHANG Yun, ZHAO Guang-dong, YANG Hong-guo, SHI Zuo-min, XU Ge-xi
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Objective To study the spatial heterogeneity of soil trace elements in Miyaluo subalpine dark coniferous forest of western Sichuan so as to provide scientific basis for soil quality evaluation, the protection of regional ecological environment and the research on biodiversity co-existence mechanism of the subalpine forest in Western Sichuan. Method A subalpine dark coniferous dynamic forest plot (400 m × 240 m) was established in Miyaluo of western Sichuan. By combining field sampling, laboratory measurement, classical statistics and geostatistical analysis, the spatial heterogeneity of 0~10 cm surface soil trace elements were analyzed, including Iron (Fe), Manganese (Mn), Copper (Cu), Zinc (Zn) and their correlations with soil pH, soil organic carbon (SOC), total nitrogen (TN) total phosphorus(TP) and total potassium (TK) Result (1) The mean content of Fe was 17.22 g·kg−1, and the mean content of Mn, Cu, and Zn were 423.09, 4.33 and 47.91 mg·kg−1 respectively; (2) The high values of soil Fe, Mn, Cu and Zn contents appeared mainly in the high altitude area of the dynamics plot eastern portion and with patch shape, the spatial distribution characteristics of soil Zn was relatively simple with strong continuity; (3) The coefficient of variance (CV) of all soil trace elements content ranged from 29.76%~63.84%. And the CVs of soil Fe and Mn were 29.76% and 63.84%. The Nugget/Sill ratio of soil trace element content ranged from 0.08 to 0.50. Mn and Cu showed a strong spatial autocorrelation, whereas Fe and Zn showed a moderate spatial autocorrelation; (4) In addition to the Cu and pH, Zn and SOC , Zn and TK, the other 17 pairs of soil properties had a significant (P < 0.05) or extremely significant (P < 0.01)correlation. Conclusion The content of trace elements Fe and Mn in the soil of the dark coniferous forest in the western Sichuan are high, but the content of Cu and Zn are low. The spatial distribution characteristics of soil Fe, Mn, Cu, Zn content show obvious spatial autocorrelation. There is a universal correlation between soil Fe, Mn, Cu, Zn content and soil pH, SOC, TN, TP, and TK.
Anther Structure and Pollen Development Characteristic of Manglietia conifera
PAN Li-qin, HAO Jian, XU Jian-min, LI Hong-lin, LIANG Fu-jiang, ZHANG Qing-qing, JIANG Qing-bin
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Objective The anther structure and microspore development of Manglietia conifera were studied to determine the abnormal phenomenon of male microspore development, and to provide evidence and accumulation data for further study on the taxonomic status of M. conifera and the phylogeny of Magnoliaceae. Method The anther structure, microspore and male gametophyte development of M. conifera were observed by means of anatomy and morphology. Result The results showed that the mature anther of M. conifera was composed of 5 to 7 layers of cells, including the surface layer, the inner wall, the middle layer and the tapetum. The 4-6 microsporangia were arranged in a linear pattern and the anther dehiscence was centripetal or lateral. There were two types of cytokinesis of microspore mother cell: continuous type and simultaneous type. The arrangement of microspore in a tetrad was isobilateral, linear or tetrahedral, and the mature pollen was two-celled. The pollen wall was smooth with very sparse cave-like ornamentation. Conclusion The anther structure and developmental characteristics of M. conifera were similar to those of other genera in Manglietia, but the structure of pollen sac, the mode of cytoplasm division and the arrangement of microspore tetrad were different. The abnormal phenomenon of microspore development mainly occurs in the tetrad stage, which is one of the reasons for the abortion the pollen and low seed setting rate of fruit.
Measurement of Species Richness of Forest Community by Maximum Tree Species Number
YANG Ai-ming, HUI Gang-ying
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Objective This paper attempts to address the forest species richness measurement by presenting a new measurement method to contribute to the forest biodiversity research. Method Monod model was adopted to express the species-area curve. The minimum forest community area and the maximum number of tree species were determined by mathematical means. Result The method applied in this study have been used to measure forest species richness in different climatic zones and the results further prove the fact that there are higher maximum species number and larger minimum community area in tropical forest communities and confirm the general rule that species richness decreased gradually with climatic zones from tropical to cold temperate zones. Conclusion The maximum number of tree species can accurately express the tree species richness of forest communities in different climatic zones, which overcomes the disadvantages of directly taking the number of tree species in survey areas of different sizes as the tree species richness in current studies.
Site Classification and Quality Evaluation of Eucalyptus urophylla × E. tereticornis Plantation in Leiqiong Area, China
ZHANG Pei-jian, LU Wan-hong, XU Jian-min, LIN Zhi-feng, CHEN Ma-xing, LI Kong-sheng
, Available online  
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Objective To study the site type and quality evaluation of Eucalyptus urophylla × E. tereticornis plantation in Leiqiong coastal area, so as to provide reference for site selection and production potential promotion of E. urophylla × E. tereticornis plantation in Leiqiong area. Method 112 plots were set up in 1- to 18-years-old E. urophylla × E. tereticornis plantations in Leizhou and Hainan. The growth indexes of E. urophylla × E. tereticornis were investigated, the site factors were recorded, and soil samples were collected to determine the soil physical and chemical properties. The quantitative theory I was used to establish the relationship model between site factors and the dominant high annual mean growth of E. urophylla × E. tereticornis, the site classification and quality evaluation of E. urophylla × E. tereticornis plantation were carried out by k-means cluster analysis and correlation analysis. Result The multiple correlation coefficient between site factors (altitude, slope, soil depth, parent rock, pH value, soil texture, and soil density) and the height growth of the dominant tree was 0.712, which was highly significant (P < 0.01). Soil texture, parent rock and soil density were the main site factors affecting height growth of dominant trees of E. urophylla × E. tereticornis. According to these factors, E. urophylla × E. tereticornis plantation in Leiqiong area could be divided into 16 site types. According to the suitability and productivity, the site quality was evaluated and divided into four grades: high yield group, middle yield group, low yield group and poor yield group. The total proportion of the most suitable, more suitable and suitable grades was 91.89%, which indicated that the distribution of E. urophylla × E. tereticornis plantation area in Leiqiong area was basically reasonable. The soil factors such as pH, organic matter, total phosphorus, total potassium and available potassium had significant effects on the growth of E. urophylla × E. tereticornis plantation. Conclusion Most of the site conditions in Leiqiong area are suitable for the growth of E. urophylla × E. tereticornis. When planting E. urophylla × E. tereticornis plantation, it is suggested to choose the high yield group sites with acid loam soil and medium and low density. In afforestation and tending management, it is necessary to supplement phosphorus and potassium fertilizer in time to give full play to the production potential of forest land, timely replant the unsuitable site to improve the scientificity and rationality of afforestation.
Response of Soil Labile Organic Carbon to Thinning Intensity in Secondary Forest of Cyclobalanopsis glauca
QI Meng-juan, SHI Shuo-rong, JIANG Chun-qian, WANG Shu-ren, WANG Hui, WANG Jing-di
, Available online  
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Objective To study the response of soil labile organic carbon to thinning intensities in the secondary forest of Cyclobalanopsis glauca. Method Experiments were carried out to investigate the changes of SOC and its labile chemical components (MBC, DOC, POC and ROC) as well as their distribution ratio following a short term intensity adjustment of stand woods with 4 treatments: light (15%, LIT), moderate (30%, MIT), high (50%, HIT) and the contrast (unthinning, CK) in secondary forest of Cyclobalanopsis glauca. Result (1) Compared with the CK, the MIT and HIT significantly increased the SOC content, while LIT reduced the SOC content. (2) Thinning increased the soil MBC content and reduced the DOC content. The variation trend of soil POC and ROC contents under different thinning treatments was consistent with that of the SOC. (3) Under different thinning intensity, the distribution proportion for soil MBC and POC, DOC and ROC were 0.23%-0.54%, 0.40%-0.78%, 16.54%-47.30% and 6.46%-14.29%, the HLT significantly Increased the proportion of MBC allocation as well as POC and ROC and reduced the allocation proportion of DOC, showing that thinning treatments increased the proportion of unstable carbon and POC was more sensitive to the thinning processing. (4) Correlation analysis showed that there was a significant positive correlation between soil total organic carbon and labile organic carbon components, and labile organic carbon was positively correlated with soil water content and total nitrogen content, the carbon conversion of soil labile components was dependent on the change of total organic carbon, and it was easy to decompose under certain water and nitrogen conditions. Conclusion Thinning treatment has significant effects on the contents of soil organic carbon and its labile components, and HLT will significantly increase the contents of soil organic carbon and its labile components and accelerate the carbon cycle in the soil.
Cloning and Functional Analysis of JcBRL3 Gene from Jatropha curcas During Flower Development
CHEN Yu-qian, LEI Shi-kang, XU Gang
, Available online  
Abstract:
Objective To explore the function of BRL3 gene in flower development of Jatropha curcas. Method The full-length cDNA sequence of JcBRL3 gene was obtained by RACE PCR. The prokaryotic expression system was used to induce the expression of JcBRL3 gene. The expression products were identified by mass spectrometry using LC-MS/MS. The structure and basic physicochemical properties of the protein were analyzed by bioinformatics. The relative expression levels of JcBRL3 gene during the key stages of flower development of Jatropha curcas were analyzed by qRT-PCR. The overexpression JcBRL3 gene was transformed into tobacco by leaf plate method to analyze the influence of overexpression of JcBRL3 gene on the morphology and structure of tobacco flowers. Result The length of the open reading frame of JcBRL3 gene was 3 618 bp and encoded 1 205 amino acids. The results of mass spectrometry showed that the expression of this gene encoded a JcBRL3 protein. Protein structure analysis showed that JcBRL3 protein was a transmembrane protein with multiple leucine-rich repeats and conserved repeats: LxxLxLxxN/CxL. qRT-PCR analysis showed that the expression of JcBRL3 in female flowers reached the highest level at mononuclear embryo sac stage, and in male flowers reached the highest level at pollen grain maturation stage, which was significantly higher than at any other stage. The morphological structure analysis of transgenic tobacco flower showed that the stigma position of transgenic tobacco was lower than that of anther, and the malformation rate of pollen grains was lower. Conclusion JcBRL3 protein is a LRR-RLK, which is a membrane protein. JcBRL3 gene may participate in the development process of female flower mononuclear embryo sac stage and pollen grain maturation of male flower and promote filament elongation in Jatropha curcas.
Comparison of Deep Learning and Traditional Models to Simulate the Height-DBH Relationship of Chinese Fir
LIANG Rui-ting, SUN Yu-jun, LI Yun
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Abstract:
Objective To explore a more efficient and low-biased tree height prediction method, improve the prediction accuracy of tree height, and to establish a multi-hidden layer neural network model of height- diameter is based on deep learning algorithm. Method Using a set of 2898 groups of tree height and diameter data from 34 Chinese Fir (Cunninghamia lanceolata) sample plots in Jiangle National Forest Farm of Fujian Province, 10 generalized height-diameter models were established based on traditional regression, and the model with the highest accuracy was selected to compare. At the same time, based on the deep learning algorithm of the H2O platform, 70 DLA models with different structures of tree height-diameter at breast height were established. Through analysis and comparison, the most suitable model structure was determined and compared with the traditional optimal model. Result The different height-diameter DLA models can describe the relationship between height and diameter of Chinese Fir well, whose R2 is above 0.84, which is higher than that of the best traditional model, and the RMSE and MAE are smaller than that of the traditional model. The most accurate DLA model structure contains 6 hidden layers, each with 340 neurons. Conclusion The height-diameter DLA model established based on deep learning has higher fitting accuracy and prediction accuracy than the traditional models, especially when predicting higher trees. It can be used to predict the height of Chinese Fir in study area.
Remote Sensing Monitoring and Restoration Evaluation of Ecological Environment in Shennongjia Area
QI Zhao, YU Xin-wen, TAN Bing-xiang, DENG Guang, YU Hang, SHEN Ming-tan
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Abstract:
Objective To monitor and evaluate the change of ecological environment by using vegetation coverage change information in Shennongjia Forest Region, Shennongjia Nature Reserve and outside the reserve in the past two decades, combined with forest management activities and governance methods in different periods. Method Taking Shennongjia Forest Region, Shennongjia Nature Reserve and outside the reserve as the research area, using the three phases of Landsat remote sensing images in 1999, 2007 and 2019 to estimate the vegetation coverage of the study area based on dimidiate pixel model, and the method of difference analysis was used to calculate the vegetation coverage changes in each region. The results were evaluated and analyzed in conjunction with the changes in national policies and business activities in different period. Result From 1999 to 2019, the mean forest vegetation coverage (FVC) of Shennongjia Forest Region increased by 8.25%, the area with high FVC accounted for 97.50%. The vegetation coverage in protection zone has been better than that out of protection zone in the early stage, but in the late stage, the difference of vegetation coverage in and outside the protected zone is smaller. Conclusion In recent 20 years, the vegetation coverage of Shennongjia Forest Region has been on the trend of increasing, and the ecological environment has gradually become balanced, which indicates that the establishment of nature reserves, the natural forest protection project and the conversion of farmland to forest project are effective for the restoration of the regional ecological environment.
Differences in the Response of Radial Growth and Intrinsic Water Use Efficiency of Robinia pseudoacacia to Climatic Factors in Minquan of He'nan Province and Baishui of Shaanxi Province
ZHOU Jia, MENG Ping, ZHANG Jin-song, GUAN Chong-fan, SUN Shou-jia
, Available online  
Abstract:
Objective To analyze the response of radial growth and intrinsic water use efficiency (WUEi) of Robinia pseudoacacia to climate factors at different locations, and to determine the dominant factors affecting the growth and water use mechanism, so as to provide reference for the management of R. pseudoacacia plantations in China under climate change. Method The ring width chronologies were established in Minquan (MQ) of He'nan Province and Baishui (BS) of Shaanxi Province. The stable carbon isotopic composition (δ13C) of tree ring was measured to calculate the WUEi. The differences in the response of R. pseudoacacia to climatic variation were analyzed with meteorological data. Result The plantations at the two locations were in similar age. The tree-ring width at BS presented a trend of initially increasing and thereafter decreasing with the increase of tree age, whereas at MQ, the tree-ring width showed a linear decreasing trend with tree age increase. The trends of basal area increment (BAI) of R. pseudoacacia at the two locations were similar, presenting a trend of initially increasing and thereafter decreasing with the increase of tree age. The δ13C value and WUEi of the trees in MQ were lower than those of BS. The Pearson correlation results showed that on a monthly scale, the STD index of R. pseudoacacia in the two locations was mainly positively correlated with the summer precipitation and drought index (SPEI) (P < 0.05), and the R. pseudoacacia in BS was significantly negatively correlated with the average precipitation and SPEI in November of the previous year (P < 0.05). The WUEi of trees in MQ was significantly positively correlated with the average temperature and maximum temperature in March and August (P < 0.05), while that of trees in BS was significantly positively correlated with the average temperature, maximum temperature and minimum temperature from March to April of the current year, and June to July of the previous and current year (P < 0.05). The path analysis model showed that on the annual scale, the STD index of R. pseudoacacia in BS had a significant positive effect on the average precipitation and average temperature (P < 0.05), while the R. pseudoacacia in MQ had no significant response to climate factors. The annual average temperature had significantly positive effect on WUEi of trees at both the locations (P < 0.05). Conclusion The average precipitation is the dominant factor influencing the radial growth of R. pseudoacacia at both the locations, and the sensitivity of growth of trees in BS is higher than that of trees in MQ. The average temperature is the dominant factor influencing WUEi at the two locations, and the WUEi of trees in BS is more sensitive to the temperature than that of trees in MQ.
Correlation between External Color and Quality of Mulched Phyllostachys violascens Shoots
HE Yu-you, CHEN Shuang-lin, GUO Zi-wu, XU Sen
, Available online  
Abstract:
Objective To study the change of appearance color and the relationship between color and quality of Phyllostachys violascens shoots from mulched forest land in order to provide references for bamboo shoot production, management and quality evaluation. Method The color parameters, including lightness value (L), redness value (a), and yellowness value (b), in the lower, middle and upper parts of sheath and pulp were determined by colorimeter, and statistical analysis methods such as principal component analysis, cluster analysis, discriminant analysis, ANOVA and correlation analysis were carried out for these color parameters and morphological characters of mulched Ph. violascens shoots. Result The results showed that the L, a, and b of the middle and upper parts of bamboo sheaths were the main color parts and chromaticity factors of the bamboo shoot appearances. The color of bamboo shoots could be divided into three types (dark, medium and light) based on L × a × b clustering. The consistent rate of discriminant analysis and cluster analysis was 95.6%, and the accuracy of regression validation was 93.3%, showing highly feasible and well effective of the clustering method. There were significantly differences in the color of bamboo sheath and bamboo pulp among different color types of mulched Ph. violascens shoots, the same with the morphology of shoot and its sheath, the edible rate, etc., and a strong correlation existed between the internal and external products of the bamboo shoots. Bamboo shoots with lighter color had a well-proportioned yellowish-white appearance, bright white pulp, small and thin sheath, light-weighted stump, and the edible rate was higher by more than 11% compared with that of the darker ones. Conclusion The bamboo shoots of mulched Ph. violascens have abundant changes in appearance traits such as color, morphology, etc., and generally, light-colored bamboo shoots possess more appearance quality advantages.
Research of Climate-sensitive Stand Biomass Model for Larix gmelinii Plantation
HE Xiao, XU Qi-gang, LEI Xiang-dong
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Abstract:
Objective To Establish stand biomass model and analyze the effects of stand factors and climatic factors on stand biomass, so as to provide a model for the biomass estimation for regional scale. Method Taking Larix gmelinii plantations from 7 provinces in Northeast and North China as samples, the data from 8th national forest inventory of fixed sample plots were used to establish the basic stand biomass models of aboveground and total base on log-transformed by least square regression and robust regression, respectively. The climate variables were screened by principal component analysis and correlation analysis, and climate-sensitive stand biomass models (including aboveground biomass AGB and total biomass TGB) were established. The determination coefficient (R2), root mean square error (RMSE) and relative root mean square error (rRMSE) were used to evaluate the models. The interpretation rate of each factor was divided into independent interpretation and covariant parts and the interpretation rate of different factors was quantified. Result (1) The form of the optimal basic model was the direct introduction of variables. The R2 of the optimal AGB and TGB models were 0.967 and 0.953, respectively, and the AGB were larger than the TGB biomass. The result of ordinary least square regression was similar to that of robust regression, and robust regression was slightly better than ordinary least square regression. The RMSE and rRMSE of the optimal model based on robust regression were lower than the corresponding ordinary least square regression for AGB by 0.046 t·hm−2 and 0.085%, respectively, and for TGB by 0.059 t·hm−2 and 0.081%, respectively. (2) The correlation coefficients between AGB, TGB and moisture-heat index (AHM) were −0.350 and −0.363, respectively. The climate-sensitive stand biomass model further improved the prediction effect of the model. The R2 of AGB increased by 0.41%, while RMSE and rRMSE decreased by 6.85%. The R2 of TGB increased by 0.63%, and the error statistics decreased by 6.79%. (3) The independent interpretations of stand factor of AGB and TGB were 87.37% and 82.32% respectively, the independent interpretations of climate factor were 0.40% and 0.60% respectively, and the covariant parts were 9.33% and 9.98%. The interpretation rate of stand factor was much higher than that of climate factor and the covariant part was large. Conclusion When the modeling data quality of the stand biomass model is high, there is little difference between the models established by robust regression and ordinary least square regression, but climate factors have a significant impact on stand biomass. It is necessary to establish a climate-sensitive stand biomass model to estimate the biomass.
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  
Abstract:
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  
Abstract:
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.