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25 May 2017, Volume 53 Issue 5
Eco-Physiological Characteristics of the Exotic Plant Rhus typhina in Comparison with Its Indigenous Congeners Rhus chinensis
Bu Qingmei, Hou Yuping, Fang Hongkun, Zhang Zhiliang, Bai Xinfu
2017, 53(5):  1-7.  doi:10.11707/j.1001-7488.20170501
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[Objective] Rhus typhina is an exotic tree species widely planted in the Yellow River basin and North China, but there is still controversy about whether it is an invasive plant. This paper explores the eco-physiological mechanism of R. typhina invasion by comparing it with its indigenous congeners Rhus chinensis in terms of their photosynthetic performance, resource-use efficiency, and construction cost to provide a reference for the comprehensive prevention and control of R. typhina, or planting. [Method] In this study, the photosynthetic performance parameters of R. typhinaand R. chinensis were measured with a TPS-2 photosynthetic system; the light use efficiency (LUE) and water use efficiency (WUE) were calculated according to the related parameters. The total nitrogen content of leaves was analysed with a Vario Micro Cube element analyzer. The gross calorific value was evaluated with a C2000 oxygen bomb calorimeter, and the leaf photosynthetic nitrogen use efficiency (PNUE) and construction cost were thus calculated. [Result] The apparent quantum efficiency (AQY), maximum net photosynthetic rate (Pmax) and respiratory rate in R. typhina were higher than those of its indigenous congeners R. chinensis, but the differences were significant (P<0.05) only in September. The light saturation and compensation point and chlorophyll content were not significantly different (P>0.05) between the two species. The LUE and PNUE of R. typhina were significantly higher than those of R. chinensis(P<0.05) in September, but the WUE of the latter was significantly higher than that of the former in July. The gross caloric value, mass-based (CCmass) and area-based (CCarea) leaf construction cost were all lower in R. typhina than in its indigenous congeners R. chinensis, but the reverse was the case in terms of the specific leaf area (SLA). Furthermore, the two-factor analysis of variance showed that the differences of the photosynthetic performance indices, resource-use efficiency indicators and leaf construction cost between the two species were insignificant (P >0.05), but differences in the indexes among different measurement periods were very significant (P<0.01). It is therefore concluded that although the photosynthetic capacity, resource-use efficiency inR. typhina is higher compared with R. chinensis at the later stage of the annual growing season (September), there is no significant difference in those indexes between the two species as a whole. [Conclusion] Compared with its indigenous congeners R. chinensis, R. typhina has some characteristics of invasive plants in physiological and ecological property, but the competitive advantage only appeared in the later stage of the annual growing season.
Effects of Drought Stress on Anatomical Structure and Photosynthetic Characteristics of Transgenic JERF36 Populus alba×P. berolinensis Seedling Leaves
Huang Juan, Chen Cun, Zhang Weixi, Ding Changjun, Su Xiaohua, Huang Qinjun
2017, 53(5):  8-15.  doi:10.11707/j.1001-7488.20170502
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[Objective] In this study, transgenic Populus alba×P. berolinensis line (ABJ01) and non-transgenic line (9#) were used to test effects of drought stress. To provide a new reference for drought assessment and scientific basis for promotion and application of transgenic poplars, seedling height, morphological and anatomical structure of leaves, and photosynthetic characteristics of transgenic poplar and non-transgenic poplar under drought stress were measured. [Method] At the end of June 2015, a soil drought stress experiment was conducted with seedlings of transgenic poplar and non-transgenic poplar at the average height around 45 cm. The seedlings were subjected to three regimes of water (control, moderate stress, and severe stress), and the soil moisture was controlled at 60%-80%, 40%-60%, 20%-40% of the field water capacity, respectively for 30 days. [Result] Seedling height growth of the two lines was inhibited to a certain degree by drought stress, and the inhibition was increasing severe with the stress level increased. The seedling height of transgenic line ABJ01 was 9.38% higher than non-transgenic line 9# under severe drought stress. Single leaf area of the two lines was significantly reduced under drought stress, indicating that drought stress suppressed growth of poplar leaves. Single leaf area of 9# was significantly lower than ABJ01, accounting for 10.82% and 13.79% of the control, respectively, indicating limitation of leaf growth in ABJ01 was lower under drought stress. Anatomical structure of leaves showed that growth of leaf epidermal cells and mesophyll cells in ABJ01 and 9# were inhibited by drought stress, however the inhibited degree of ABJ01 was lower. Under moderate drought stress, leaf upper epidermal thickness and lower epidermal thickness of ABJ01 were 5.55% and 4.70% significantly greater than that of 9#, respectively. Thickness of palisade tissue of ABJ01 was 6.17% significant greater than 9#. In contrast, sponge tissue thickness and SR were 12.35% and 12.38% significantly lower than those of 9#, respectively. Under severe drought stress condition, leaf upper epidermal thickness and lower epidermal thickness of ABJ01 were 16.27% and 10.05% significantly higher than 9#, respectively, but sponge tissue thickness and SR were 11.71% and 11.58% significant lower than those of 9#, respectively. The more developed palisade tissue and relatively reduced spongy tissue may facilitate the conduction of CO2, and maintain the higher Pn in leaf of ABJ01, which would contribute to adaptation to drought stress. Photosynthetic physiological data suggested that Pn of 9# was 2.8 times lower than that of ABJ01, and ABJ01 Pn was significantly higher than non-transgenic lines 9# (10.50%-18.97%), indicating ABJ01 had a greater photosynthetic capacity. Under control treatment, there were no significant differences in Gs, Fv/Fm between the two lines. However under drought stress, the decreased trend in transgenic line was relatively smaller compared with non-transgenic line under drought stress, indicating that ABJ01 indexes was less affected by drought stress. In addition, ABJ01 Tr was less than 9#, suggesting that ABJ01 had stronger capacity in water holding under drought conditions. The chlorophyll a, chlorophyll b and total chlorophyll content in ABJ01 were higher than those of 9#. ABJ01 Fv/Fm was higher than 9#, indicating that the ability of maintaining the stability of chlorophyll content was stronger and the damage of PSⅡ was less in transgenic line. [Conclusion] The study suggests that exogenous gene JERF36 may improve the gas exchange capacity and water-holding capacity of transgenic Populus alba×P. berolinensis under drought stress by impacting the leaf structural of transgenic poplar, finally enhance drought tolerance of transgenic Populus alba×P. berolinensis.
Assessing Leaf Water Status of Eucalyptus Using NIRS
Lu Wanhong, Yang Guili, Lin Yan, Wang Chubiao, Luo Jianzhong
2017, 53(5):  16-22.  doi:10.11707/j.1001-7488.20170503
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[Objective] [Objective] The aim of this study was to monitor the leaf relative water content (RWC) and water potential (Ψw) in structured Eucalyptus camaldulensis and E. tereticornis populations by Near Infrared spectroscopy (NIRS). [Method]The samples were collected from the breeding population, which contained 21 families of 7 provenances for E. camaldulensis, and 26 families of 5 provenances for E. tereticornis. A total of 20 average-growth seedlings per family were chosen, divided into 5 groups randomly, and were watered every day by replenishing 100%, 70%, 50%, 30% and 0% of the average water loss of these seedlings from pots by evapotranspiration, respectively. In 60 days after water controls, three seedlings per water control and per family were chosen, of which the top second pair fully expanded leaves were used to be scanned with a portable near infrared spectrometer for getting the NIRS spectra. After the scanning, the leaf RWC and leaf Ψwwere measured. The measurements were conducted once a day for consecutive 18 days.[Result] The results showed that there was a close relationship between water status traits and the raw NIRS at 1 860-1 960 nm. However, after the transform of the 2nd derivate preprocess for raw NIR spectra, there were significant differences of leaf RWC and Ψw among all samples in the whole range of NIRs. The NIRs calibrated PLS(partial least squares) model for the prediction of leaf RWC and Ψw both showed a good fitting. The correlation coefficient between predicted and measured value (R2) were 0.92 and 0.84 for leaf Ψw and RWC, respectively. The average differences between predicted and measured values (RMSE) were 0.25 and 1.31 for leaf Ψw and RWC, respectively. [Conclusion] The coefficient of variation curve showed that the information of whole NIRS range should be used to calibrate the PLS model for the water status traits associated physiological characters in Eucalyptus. All the findings in this study highlight the advantages and perspectives of NIRS in monitoring leaf water status traits in structured Eucalyptus populations.
Cloning and Expression Analysis of MYB Homologous Gene PwMYB20 from Picea wilsonii
You Hanli, Yuan Yihang, Li Changjiang, Zhang Lingyun
2017, 53(5):  23-32.  doi:10.11707/j.1001-7488.20170504
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[Objective] MYB is the largest family of transcription factor in plants, which is widely involved in the regulation of plant life and play an important role in both plant development and growth,and in the regulation of stress resistance. Cloning and analysis of MYB homologous gene PwMYB20 in Picea wilsonii is propitious to explore the function of PwMYB20 in plant growth and development, for the purpose of efficient use of high-qualified genes in Picea wilsonii.[Method]The PwMYB20 was cloned and verified based on the cDNA library of the EST sequence of PwMYB20 with RACE-PCR method. ProtParam, ProtScale, FoldIndex and other bioinformatics software were used to analyze and predict the physical and chemical properties of PwMYB20. The homologous proteins were obtained by BLAST online tools, and their comparative analysis and phylogenetic tree analysis were carried out. The tissue specific expression of PwMYB20 in different tissues,as well as the changes of PwMYB20 expression with drought, cold, NaCl and ABA treatments were analyzed using real-time quantitative PCR. Furthermore, subcellular localization and transcriptional activation assay were carried out to reveal its biological properties.[Result]The full length of PwMYB20 cDNA was 966 bp with an open reading frame (ORF) of 675 bp encoding 225 amino acids. ProtParam analysis showed that the protein molecular formula is C1104H1740N340O330S8, molecular weight is 25.3 kDa and isoelectric point is 9.11. Hydrophobicity analysis with Protscale showed that the hydrophobic sites of PwMYB20 were uniformly distributed, suggesting that the protein is hydrophilic. No protein peptide domain was found with SignalP. Furthermore, Protein inherent disorder analysis showed the protein contains many inherently disordered sequences. In addition, TMHMM tools predicted that the protein has no transmembrane domain. BLAST online tools analysis showed that PwMYB20 belongs to the MYB family gene, which encodes a R2R3-MYB protein. The results of phylogenetic tree analysis showed that PwMYB20 and PgMYB20 were clustered into one cluster. The real-time quantitative PCR analysis indicated that PwMYB20 expressed constitutively at a high level in seed, followed by needle, and the least was in pollen. The expression of PwMYB20 displayed responses to drought, cold and ABA treatments, but slightly to NaCl treatment. With drought treatment, the expression of PwMYB20 was up-regulated at the early stage, and then decreased after 6 h. Additionally, the expression of PwMYB20 was induced when it was 4 ℃ treated for 3 h, 12 h and with a fluctuation in 6 h, the expression showed an up-down-up trend. Moreover, the expression of PwMYB20 was induced by ABA continuously. Subcellular localization analysis showed that PwMYB20 was mainly localized in the nucleus. Transcriptional activation analysis revealed that C terminal of PwMYB20 had a transcriptional activation activity, whereas the full-length PwMYB20 and its N terminal had no transcriptional activation activity.[Conclusion] The results indicated that the expression of PwMYB20 was constitutive in different tissues, and induced by drought, cold and ABA. In addition, PwMYB20 was located in the nucleus. Its C terminal had a transcriptional activation activity, although its full length is not activated.It is widely involved in responding to different stresses.
Cloning and Expression Analysis of Phosphate Transporter Gene ClPht1;1 in Cunninghamia lanceolata
Su Shuoshuo, Li Ming, Wu Pengfei, Zhang Ying, Ma Xiangqing
2017, 53(5):  33-42.  doi:10.11707/j.1001-7488.20170505
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[Objective] PHT1 gene family is one of the important phosphorus transporters which affect the uptake of phosphorus in plants. A Cunninghamia lanceolata phosphate transporter gene of PHT1 gene family was cloned from No.32 phosphorus efficient C. lanceolata cDNA,and the temporal and spatial expression of ClPht1;1 under different levels of phosphorus stress was studied to lay the foundation for the research of PHT1 gene sequence characteristics, functional structure and the selection of the C. lanceolata genotype which is efficient in phosphorus utilization.[Method] According to the designed degenerate primer based on the conserved sequence of PHT1 gene family, the target gene ClPht1;1 cDNA sequence was obtained by amplification of the root cDNA of the P-efficient family No.32 of C. lanceolata as the template, the full length of the target gene was cloned by RACE technique, and analyzed its sequence characteristics, homology and protein structure were then analyzed. The real-time fluorescence quantitative PCR was used to detect the expression of ClPht1;1 in roots, stems and leaves of No.32 C. lanceolata with high P-efficiency, differential expressions of ClPht1;1 in the roots of C.lanceolata families of No.4,No.15,No.25,No.27,No.28 and No.32 in different P-utilization efficiency under moderate P deficiency stress, and the ClPht1;1 expression change with time in the root system of phosphorus efficient C.lanceolata No.32 under moderate and severe phosphorus deficiency stress.[Result]A C.lanceolata PHT1 gene was cloned and named ClPht1;1(GenBank accession number KJ493165). The coding region of the gene sequence was 1 638 bp, code 545 aa protein. ClPht1;1 encoded proteins were composed of 12 hydrophobic transmembrane domains, including 1 suspected transmembrane domains. Each transmembrane domain was composed of 17-25 amino acid residues, and the N and C ends of transmembrane proteins were located in the cytoplasm, and the conserved sequences were located in the fourth transmembrane domains. The main skeleton of the protein was α-helix, no signal peptide sequence. The similarity of amino acid sequences of encoding proteins of ClPht1;1 was 87% with Cryptomeria japonica PHT gene, and above 75% with Populus, Camellia, Pinus massoniana etc. PHT family gene. ClPht1;1 genes were expressed in root, stem and leaf of C.lanceolata, and the highest expression was in root,the lowest was in leaf; Under moderate P deficiency stress, the expression level of ClPht1;1 in the root of C.lanceolata varied among families in a order of No.25 > No.27 > No.4 > No.15 > No.32 > No.28. Under moderate and severe P deficiency stresses, the expression of ClPht1;1 in the root of No.32 increased with the extension of stress time; The expression level of ClPht1;1 was gradually decreased to normal level after the recovery of phosphorus supply; ClPht1;1 gene expression in severe P deficiency stress was higher than that under moderate P deficiency stress.[Conclusion] ClPht1;1 gene has the typical structure of PHT1 gene family, and its protein amino acid sequence is highly similar to the amino acid sequences of Cryptomeria japonica phosphate transporter protein, it is a member of the high affinity phosphate transporter PHT1 gene family of C.lanceolata. ClPht1;1 gene was mainly expressed in root of C.lanceolata, and its expression was lower in leaf. The stronger the phosphorus use efficiency, the higher the ClPht1;1 gene expression in its roots.There were large differences in the expression level of ClPht1;1 gene among families with different phosphorus use efficiencies. ClPht1;1 gene expression was induced by low phosphorus stress; Under P deficiency stress, the expression level of ClPht1;1 was significantly increased, and the expression of ClPht1;1 gene was significantly decreased after the recovery of phosphorus supply.

Analysis of Genetic Diversity in Schima superba Plus Tree Germplasms by SSR Markers
Yang Hanbo, Zhang Rui, Wang Bangshun, Xu Zhaoyou, Chen Huanwei, Zhou Zhichun
2017, 53(5):  43-53.  doi:10.11707/j.1001-7488.20170506
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[Objective] As a precious broadleaf timber and an efficient tree species for biological fire prevention, Schima superba plays an important role in commercial timber production forests and ecological fireproof forest construction. In depth studies of genetic diversity of S. superba plus tree clones using SSR markers are particularly important for conservation, utilization of genetic resources, and future breeding programs for this plant species. [Method]A total of 734 clones of S. superba plus trees from 24 areas of five provinces in China, were analyzed systematically with 10 SSR primer pairs. The GenAIEx 6.5 and CERVUS software were used for genetic diversity parameters calculation, principal coordinates analysis (PCoA) and null alleles detection. NTSYS software was used for cluster analysis based on the matrix of Nei’s genetic identity. The Arlequin software was used for analysis of molecular variance (AMOVA). STRUCTURE 2.3 software was used to analyze genetic structure. [Result]The results showed that 105 alleles were detected among the germplasm accessions, with an average of 10.5 alleles per pair of primers. The maximum number of alleles was detected in primer ss16 with a value of 16. The Shannon’s information index (I) was ranged from 1.121 to 1.908, with an average of 1.473. The polymorphism information content (PIC) was ranged from 0.557 to 0.807, with an average of 0.668. The expected and observed heterozygosity were 0.713 and 0.735, respectively. The results of principal coordinate analysis (PCoA) and genetic structure analysis were basically consistent with each other, the 734 clones were divided into three groups in PCoA or five subgroups in STRUCTURE analysis. The genetic distance of 24 populations were ranged from 0.030 to 0.804, with an average of 0.230. The results showed that there were close genetic relationship between populations, but, there were still larger genetic distances between some populations, such as HNSZ and GDSX, JXFY and FJSX, etc. The Shannon’s information index (I) of populations were ranged from 0.980 to 1.431, and the genetic diversity was not significantly correlated to geographic distribution. The results of genetic structure analysis indicated that 71.1% S. superba plus tree clones displayed a simple genetic structure, and the rest 28.9% displayed a mixed genetic structure. The AMOVA results showed that the differentiation among populations contributed to 5.91% of the total genetic variation, and the differentiation within populations contributed 94.09% of the total genetic variation.[Conclusion] All the results showed that there was a high level of genetic diversity in S. superba plus tree germplasms, and a significant difference of genetic diversity among populations. When selecting mating parents,the mating pairs should be geographically distant, and genetic relationship between populations or individuals should also be taken into account.
Early Selection of Interstocks for Improving Grafting Compatibility in Diospyros kaki ‘Fuyu’
Tang Dan, Jiang Xibing, Gong Bangchu, Liu Tongxiang, Xu Yan, Wu Kaiyun
2017, 53(5):  54-62.  doi:10.11707/j.1001-7488.20170507
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[Objective] Early growth and anatomic structure of grafted plants of Diospyros kaki ‘Fuyu’ with different interstocks were studied in order to screen optimum grafting combinations with good early compatibility, and to understand the mechanisms of compatibility of the interstocks.[Method]Scions from variety ‘Fuyu’ were grafted onto D. kaki ‘Lanxidahongshi’, D. kaki ‘Nantongxiaofangshi’, D. kaki ‘Jirou’, and D. kaki ‘Nishimurawase’ as interstocks (each with 10 cm and 25 cm in length respectively), and D. glaucifolia as rootstock. Comparative analysis of early phenotypic traits and physio-biochemical indicators were analyzed to evaluate growth performance and physio-biochemical characteristics of the grafted plants. Paraffin section and optical microscope technology were used to observe anatomical properties of grafting union between rootstock and interstock, interstock and scion.[Result]Interstocks and their lengths were important factors influencing early growth and anatomic structure. When D. glaucifolia was directly grafted to ‘Fuyu’ persimmon (the control), the grafted plants had a poor phonotypical performance such as low survival rate and short in plant height, and poor physio-biochemical properties, and the graft union displayed an obvious swelling (swelling index R=0.980), and at the graft union occur isolation layer (the proportion of isolation layer G=88.9%) and vessel jam (the proportion of jam vessels D=16.3%). When ‘Nishimurawase’ or ‘Nantongxiaofangshi’ were used as interstock, for the two-year-old grafted plants, the height, chlorophyll (a+b) content, photosynthetic rate, leaf and root soluble sugar contents, and root viability were very significantly higher than those observed in the control (P < 0.05). Survival rate, stem diameter, and leaf area were larger than those of the control. And both persimmons as interstock significantly reduced the values of R, G, and D. With the same length of interstock, the ranks of comprehensive evaluation score (Q) on growth traits was in the following order (according to division of intestock): ‘Nantongxiaofangshi’ > ‘Nishimurawase’ > ‘Jirou’ > ‘Lanxidahongshi’. With the same interstock, survival rate, plant height, stem diameter, leaf area, and Q were better when the length of interstock was 10 cm. G, D, and Q had a significantly negative correlation (correlation coefficients were -0.910 and -0.977, respectively; P < 0.01), demonstrating that the status of the grafting union had a direct impact on early growth and physiological properties of the grafted plants.[Conclusion]There was incompatibility when D. kaki ‘Fuyu’ directly grafted to D. glaucifolia, when D. kaki ‘Nantongxiaofangshi’ or ‘Nishimurawase’ were used as the interstock, the grafting union can be better developed consequently improving the compatibility of ‘Fuyu’ grafted to D. glaucifolia. And optimum combination was D. glaucifolia/D. kaki ‘Nantongxiaofangshi’(the length of interstock is 10 cm)/D. kaki ‘Fuyu’(Q=2.71, G=11.1%, D=0).
Effects of Nitrogen Application Rate and Frequency on Biomass Accumulation and Nitrogen Uptake of Populus tomentosa under Drip Fertigation
Xi Benye, Wang Ye, Jia Liming
2017, 53(5):  63-73.  doi:10.11707/j.1001-7488.20170508
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[Objective] This study aimed to provide recommendations for N fertilizer management of Populus tomentosa under drip fertigation. [Method] A field experiment was conducted in 2010-2012 (stand age of 3-5 years) to investigate the effects of nitrogen rate (NR) and application frequency (NF) on biomass accumulation and N uptake of P. tomentosa (clone B301) in a fast-growing pulp plantation. The experiment included six N fertigation treatments, which were a factorial combinations of three NR (115(N115), 230(N230) and 345(N345) kg·hm-2a-1) and two NF (two (F2) or four (F4) times per year). A control treatment (0 N with irrigation, CK) was also included in the experiment. Diameter at breast height, height, biomass, N uptake and soil N were measured periodically during the experiment. [Result] Under natural condition (ambient environment), the soil N supply capacity (includes apparent N mineralization (23-42 kg·hm-2a-1 in the P. tomentosa plantation of age 3-5) and soil inorganic N) could not provide P. tomentosa with adequate nutrient for optimal growth. The amount of apparent N mineralization was 23-42 kg·hm-2a-1 in the plantation of age 3-5. The trees in CK incorporated nearly 60 kg·hm-2a-1 from soil N sources, which could not maintain a high level of yield of P. tomentosa plantation. N fertigation showed a positive effect on tree growth, and especially trees under the N115F4 treatment had the highest growth rate. Total biomass (TM) in the N115F4 treatment reached 33.9 and 45.5 t·hm-2 in 2011 and 2012, respectively, which were 42% and 49% significantly higher than that in CK (P < 0.05), respectively. Variance in NR could significantly affect the TM of stand. In 2011, the TM under N115 was significantly higher than that under N230 and N345 (P < 0.05), while in 2012 it was significantly higher than N345 (P<0.05) and not significantly higher than N230(P >0.05). NF showed almost no effect on biomass accumulation, but higher NF (F4) resulted in significantly higher average annual N uptake (P <0.05). The relationship between total biomass and NR could be well fitted (P0.01, R2=0.482) with the quadratic regression equation. The optimal NR calculated from the equation was 192 kg·hm-2a-1, and its 90% confidence interval was 148-236 kg·hm-2a-1. [Conclusion] To sum up, under drip fertigation, the traditional NR (N345) in P. tomentosa plantation did not bring biomass yield benefits, and adopting drip fertigation technique could decrease the fertilizer application rate relative to the traditional fertilization technique. NF had no effect on biomass, but higher NF could be applied to increase N uptake. Thus, when apply N fertigation to 3-5 years old P. tomentosa plantation under drip irrigation, the recommended NR is 192 kg·hm-2a-1, which should be applied in four times within a year.
Statistical Object-Based Method for Forest Change Detection Using High-Resolution Remote Sensing Images
Li Chungan, Dai Huabing
2017, 53(5):  74-81.  doi:10.11707/j.1001-7488.20170509
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[Objective] Collecting forest-change information accurately, quickly and efficiently to update forest resource databases in time is critically important for scientific decision-making of forest management and forestry sustainable development, and has long been one of the major technical challenges in forest resource management.[Method]In this paper, an object-based statistical method was applied to detect forest changes in a study site located in Shangsi County, Guangxi Zhuang Autonomous Region where the forest cover has experienced frequent changes over time associated with a large number of parcels with relatively small sizes. High spatial resolution satellite images of ZY-3, GF-1 and the vector sub-compartment map of forest distribution were served as the data sources. Object features were extracted by using multi-resolution segmentation of satellite images accompanying with the thematic map.As the frequencies of the difference of the objects’ mean gray value and standard deviation of the two-temporal images were approximate the normal distributions, chi-square distribution statistic was using with the difference between object mean value and standard deviation. Therefore the change objects with abnormal statistics were flagged one by one with a statistical procedure of iterative trimming.[Result]The results indicated that for a given confidence level, the detected number of change objects decreased rapidly as the iteration number increased. When the confidence level was set at 0.95, 0.98, 0.99 and 0.999, the corresponding changed objects were labeled through 25, 23, 20 and 15 iterations, respectively. Along with changes in the confidence levels from 0.95 to 0.99, the omission rate increased,as a result, the commission rate decreased and the overall accuracy increased.The best result was achieved with the confidence level was 0.99 as the overall accuracy was 92.6% and the Kappa was 0.764 8.[Conclusion] The advantage of the method proposed in this paper was object-based and statistically driven, directly detected forest changes from the dataset generated from the image segmentation, did not rely on external information and human intervention, could be executed automatically in the entire procedure, and generated satisfactory results.Furthermore,this approach was potentially an ideal method for forest change detection.
Pathogenicity of Aseptic and Germ-Carrying Bursaphelenchus xylophilus on Pinus densiflora
Lin Li, Zhou Lei, Pan Jun, Kang Lipeng, Ye Jianren, Zhu Lihua
2017, 53(5):  82-87.  doi:10.11707/j.1001-7488.20170510
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[Objective]The aim of this study is to explore the pathogenicity of aseptic Bursaphelenchus xylophilus (pine wood nematode, PWN) and non-aseptic PWN on Pinus densiflora, to better understand the role of PWN in pine wilt disease development, and to provide useful information on pathogenicity mechanism and disease control. [Method] The embryogenic calli of P. densiflora were inoculated with aseptic PWNs under aseptic conditions and cultured for 5 days. The effect of aseptic PWNs on the activity of embryogenic callus cells were evaluated by staining the embryogenic calli with the triphenyltetrazoliumchloride (TTC) solution. Tissue-cultured microshoots and 4-year-old seedlings cultured in green house were inoculated with aseptic PWNs and non-aseptic PWNs, respectively. In 18 and 35 days after inoculation, the pine wilt ratio was recorded and the PWNs were isolated from inoculated seedlings. The pathogenicity of aseptic PWN and non-aseptic PWN on P. densiflora was analyzed. [Result]The inoculation by aseptic PWNs caused severe water stain in embryogenic calli of P. densiflora, and the TTC assay showed beige/light pink of embryogenic calli, revealing that the embryogenic cells lost viability. The embryogenic calli of control treatment remained healthy and showed bright red in TTC assay. Both the aseptic PWN and non-aseptic PWN wilted the tissue-cultured microshoots of P. densiflora. The wilting rates of the microshoots were 70% and 60% in 18 days after inoculation with aseptic PWNs and non-aseptic PWNs, respectively. PWNs were recovered from all wilted microshoots with average number of PWNs 599+567/microshoot for aseptic PWNs inoculation and 365+240/microshoot for non-aseptic PWNs. The number of nematodes recovered from wilted microshoots showed significant difference (P < 0.01) between aseptic PWN and non-aseptic PWN treatments. Fewer PWNs (10-20/microshoot) were also recovered from the remaining healthy-looking microshoots. The aseptic PWN could induce wilting of potted-seedlings of P. densiflora, as the same as non-aseptic PWN, with average of 80% wilting ratio in 35 days after inoculations. PWNs were recovered from wilted seedlings in both treatments. The number of recovered PWNs per seedling was 34 733±34 162 and 25 057±21 410 for aseptic PWNs and non-aseptic PWNs inoculations, respectively. No significant difference was found in number of recovered PWNs between the two treatments (P = 0.508). The number of recovered PWNs in two healthy-looking seedlings of aseptic PWNs treatment was 486 and 22, while only one healthy-looking seedlings of non-aseptic PWNs treatment contained 646 PWNs. [Conclusion] The aseptic and non-aseptic PWN could cause wilting of P. densiflora. The PWN is the main factor causing wilt of Japanese red pine, while the bacteria carried by the PWN are not necessary for the development of PWD.
Segregation Patterns and Phylogeny Analysis of AvrL567 Gene in Melampsora larici-populina
Yu Zhongdong, Chen Zujing, Cao Zhimin, Ren Zhengzheng, Feng Shiqiang, Zhang Yaoqi
2017, 53(5):  88-96.  doi:10.11707/j.1001-7488.20170511
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Rust fungus of Melampsora larici-populina (abbr. MLP) is a great enemy of poplar industry in China, and it threatened short rotation forest seriously, including poplars of Sect. Tacamachacae, and Sect. Aigerios, and their hybrids. [Objective]To understand the genetics of avirulence genes in their family, and to detect the phylogenic relationship of avirulence gene sequences between Chinese MLP and the other races in European and USA.[Method] Population of F1 aecia of MLP was harvested by cross-fertilization with spermogonia of physiologic race 2 (MLP2) collected from Houzhengzi (in which, isolate HZ3542 as a male maternal,incompatible with Populus purdomii) and Huoditang (in which, isolate HF2369 as a female maternal, compatible with purdomii poplar) in Qinling Mountain, and segregation pattern of avirulence genes in MLP2 family as detected and inoculating aciospores and urediospores on P.purdomii leaves in vitro. Primers were designed and selected by referring to AvrL5671-8;9-16;17-26;27-37;38-45;46-56;57-67;68-74;75-81;82-88;89-94;95-105;106-112;113-123;124-130;131-137;138-144;145-152;153-183;160-167;168-176;177-183;184-191;192-197;198-203;204-211;212-224(accession: AAS66952) in Melampsora lini. Avirulence genes were amplified by PCR homogenized technology and then sequenced. All putative sequences were revised and aligned with other avirulence genes in the related public molecular information data, and a maximum likehood (abbr.,ML) phylogeny tree was then constructed. [Result] Segregation of avirulence genes in MLP2 was coincident to the Mendel's law, and showed a single dominant heterozygous phenotype (Aa) in the incompatible isolate, and homozygote phenotype (aa) in the compatible isolate. Their F1 population in both aeciospores (P=0.01) and urediospores (P=0.05) segregated by following 1∶1 with dominant to recessive phenotype. The certification for dominant avr phenotype is revised and confirmed by combination with quality traits of necrosis and chlorosis, quantitative trait loci (QTLs) including latent days, both diameter size and density of uredinia. PCR productions were also used to test and confirm avirulence phenotype under annealing by selected primer pair AvrPr1 (5'-TAATCCTCGTTGACATCAGTC-3',5'-AAGCTTGAGAGCTCCGCTC-3'). ML phylogeny tree differentiated two groups from all tested sequences at a low bootstrap data. Among them, all Melampsora sequences were grouped together with a relatively high homology, and five of six AvrL567 sequences from China MLP2 isolates grouped into a sub-clad together with two Canada MLP sequences, and another one was grouped into another sub-clad with French MLP, USA M. lini, etc.[Conclusion] Incompatible race 2 of MLP in China was a phenotype of Aa, and its avirulence gene sequences showed a high homology with that of tested Canada isolates.
Variation in Structure and Dynamics of Insect Community in Larch Plantations under Different Soil Conditions
Gu Wei, Ma Ling, Sun Hu, Wang Lidong, Zhang Zilong
2017, 53(5):  97-106.  doi:10.11707/j.1001-7488.20170512
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[Objective]This study aimed to investigate the variation in insect community structure and dynamics in larch plantations under different soil conditions, so as to provide fundamental basis for the forest management and biodiversity conservation.[Method]This experiment was conducted at Liangshui Nature Reserve, in Xiaoxing’anling Mountains, China. The 60-year-old larch plantation, which was in the condition of close hillsides, was used for this. According to the terrain soil conditions 4 habitats were chosen in the forest, and the 4 habitats are buried-gley dark brown soil-larch plantation forest(A), thick buried dark brown soil-larch plantation forest(B), dark brown loam soil-larch plantation forest (C), typical dark brown soil-larch plantation forest(D). Three 20 m×20 m plots were established in each habitat. Insect community was investigated by sweeping net method, the tin pot trap method, shaking-off method and high branch cutting standard branch method.[Result]A total of 5 204 insects were collected, belonging to 250 species, 77 families, and 10 orders. Diptera and Hymenoptera were the dominant taxa in each habitat, but the proportion had great difference. There was great difference in seasonal dynamics of the dominant family of insect communities over the four habitats. Cluster analysis showed that insect communities of the 4 habitats were classified into two categories, habitat A and habitat B were classified into one category, habitat C and habitat D were classified into the other category. Species diversity index and evenness index of insect communities in different habitats showed C > A > B > D, richness index showed B > D > A > C, dominant index showed D > B > A > C. In time series, the species diversity index of the B habitat and the D habitat was significantly positively correlated with the evenness index and richness index, but the former correlation coefficient was significantly higher than that of the latter. In all habitats, species number order of different trophic groups showed plant feeding taxa > neutral group > predators group > parasitic taxa, but the proportion of different trophic groups had significant difference. The relative stability of the insect communities in different habitats was B > D > C > A. Principal component analysis showed that the factors that played a dominant role in affecting the insect community change were different in different habitats.[Conclusion]The structure dynamics of the insect communities in larch plantations were significantly different under different soil conditions. The higher the positive correlation coefficient of species diversity index and richness index of insect community, the stronger the community stability. At the same time, neutral insects played a significant role in regulating the relative stability of insect communities. Environment conditions of thick buried dark brown soil-larch plantation were most suitable for the occurrence and development of insect community in the 4 habitats.
Effects of Extracts of Lantana camara (Verbenaceae) Leaves on Cellulose and Detoxifying Enzymes Activities of Reticulitermes flaviceps (Isoptera: Rhinotermitidae)
Sun Lizhu, Luo Lan, Yuan Zhonglin
2017, 53(5):  107-115.  doi:10.11707/j.1001-7488.20170513
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[Objective]In order to explore the action mechanisms, the effects of 3 different solvent extracts from Lantana camara (Verbenaceae) leaves on cellulose and detoxification enzyme in the termite Reticulitermes flaviceps (Isoptera: Rhinotermitidae) were studied.[Method]Termites were fed with filter paper saturated with 3 different solvent extracts of L. camara leaves for different times, and then we measured the enzymes activities of endo-β-1,4-glycanase (EG), exo-β-1,4-glucanase (CBH), β-1,4-glucosidase (BG), carboxylesterase (CarE), glutathione-S-transferase (GSTs) and mixed-functional oxidase (MFO). [Result]The all extracts had to some degree inhibiting effects on the six enzymes activities, however there were differences in the inhibition with extracts of chloroform, ethyl acetate and petroleum ether at 6-72 h. As for the three cellulose enzymes, the chloroform extract had no significant effect on EG, but had significantly inhibiting effect on CBH and BG, especially on CBH with the highest inhibition rate of 17.61% at 72 h. The ethyl acetate extract also had inhibiting effect on the 3 enzymes activities, with relatively stronger inhibition on EG and BG, and the inhibition rate on EG was 27.18% at 48 h, and 29.28% at 24 h, respectively. The petroleum ether extract had no significant effect on CBH, but had strongly inhibited on EG and BG, with the highest inhibition rate of 39.89% on EG at 72 h. As for the three detoxification enzymes, the 3 extracts had no significant effect on CarE, but had inhibiting effect on GSTs, which mainly occurred at 12-48 h. The ethyl acetate extract had the strongest inhibition, with the highest inhibition rate of 39.54% at 36 h. The MFO activities fluctuated after being treated with 3 extracts, and the relatively stronger inhibition on the 3 detoxification enzymes occurred at 12 h and 36 h. [Conclusion] The extracts of chloroform, ethyl acetate and petroleum ether could decrease the cellulose and detoxification enzymes activities, disrupting the normal physiological metabolism.
Relationships between Bubble Parameters and Mechanical Properties of Fiber Porous Cushioning Packaging Material
Luo Yuying, Xiao Shengling, Li Chen, Chen Yanna
2017, 53(5):  116-124.  doi:10.11707/j.1001-7488.20170514
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[Objective] The purpose of this paper was to explore the relationships between the bubble parameters(porosity, pore size and distribution) and mechanical properties of fiber porous cushioning packaging materials though appropriate characterizing methods of bubble parameters. This study provided theoretical basis for the preparation of fiber porous cushioning packaging materials with excellent performance, and a reference for further study on the foaming mechanism of the materials. Moreover,it would promote the development of green cushion packaging material.[Method]Wood powder and waste corrugated paper pulp were used as main materials, while adding auxiliary materials such as foaming agent. Foamed materials with different pore structures were prepared through hot press molding method. Then the micro image of materials was analyzed by the image processing software called Image Pro Plus 6.0, the bubble parameters of different materials such as porosity, pore size and distribution were obtained. Through the static compression test and the four compression rebound test, the stress-strain curves, the buffer coefficient stress curve, the average rebound rate curve of the 4 times and the deformation energy per unit volume were obtained. Then, the relationships between the structural parameters and mechanical properties of porous materials were discussed.[Result]Different parameters (porosity, pore size and distribution) showed different relationships with the mechanical properties of the material. The relationships between porosity and mechanical properties of materials were as follows: The higher the porosity, the gentler the stress-strain curve, the lower the minimum buffer coefficient and the less the deformation energy per unit volume were observed. With the increase of porosity, the average rebound rate of the material exhibited increased first and then decreased trend. The relationships between pore size and distribution and the mechanical properties of the material were as follows: The larger the percentage of big hole area, the smaller the stress value of the material under the same strain and the minimum buffer coefficient were obtained. The smaller the percentage of big hole area, that was, the more uniform the pore size distribution was more uniform, the higher the average rebound rate, the bigger the deformation energy per unit volume were achieved.[Conclusion] Through appropriate characterizing, experimental and statistical methods, different parameters (porosity, pore size and distribution) of fiber porous cushioning packaging material were characterized. The relationships between mechanical properties and pore parameters of different pore structure materials were obtained. These findings had important implications for the in-depth study on micro-structure of fiber porous cushioning packaging material, optimizing the pore morphology and uniformity, and even following production and preparation.
Measuring and Analyzing the Impact of Sloping Land Conversion Program on Rural Households' Income Inequality——Shapley Value Decomposition Approach for Total Income Decision Equation
Liu Hao, Chen Sikun, Zhang Minxin, Liu Can
2017, 53(5):  125-133.  doi:10.11707/j.1001-7488.20170515
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[Objective] The objective of investigating the effect of the sloping land conversion program (SLCP) on rural households’ income inequality is to verify the process of the SLCP, and some policy implications are considered for the next stage of the SLCP. [Method]Total income decision equations were built using unique panel dataset of 1 158 sample rural households from 15 counties in 5 provinces and 1 region to consider the marginal and the overall effects. The effect of the SLCP on rural households’ total income was estimated with Shapley value decomposition approach by GINI coefficient, Theil-L coefficient and Theil-T coefficient. [Result]The empirical results indicated that the overall effect and marginal effect of the SLCP on rural households’ total income were positive and significant at 0.01 statistical level. The contribution of the SLCP to GINI coefficients of both the overall effect and marginal effect of rural households’ income inequality had been rising, and then declining from 1999 to 2012. The contributions in 2008 of both the overall effect and marginal effect were the highest with 3.04% and 4.55%, respectively. Both Theil-L coefficient and Theil-T coefficient informed us the similar consequences.[Conclusion] The implementation of the SLCP increased the sample rural households’ income, and also caused their income disparity. Therefore, attentions should be paid to the impact of the ecological restoration programs on the income inequality of rural households. Multi-win policies should be designed to tackle the matter for ecological restoration to raise rural households’ income and reduce income equality.
Study on the Entrepreneurial Psychology and Behaviors of Forest Farmers Based on Prospect Theory
Lü Weilin, Wen Zuomin
2017, 53(5):  134-145.  doi:10.11707/j.1001-7488.20170516
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[Objective] Currently many researches focus on the influence factors of culture, economy and policy on the famer entrepreneurship. This study investigated the influence of psychological factors on the famer entrepreneurship, in order to find the most important factor and to provide the key data for the further research on this topic. [Method] This paper used prospect theory as a descriptive model of decision-making. The current majority of prospect theory study was conducted on consumer groups and investment decision-making, such as investment management, national policy development, however, less attention was paid on individuals. From the perspective of prospect theory as the start point of view, this study combined psychology with economy. The prospect theory was extended to the areas of production, especially agricultural production based on family units as individual decision, to determine the effects of psychological entrepreneurial farmers and thus the influence on behaviors of entrepreneurship. In this paper, the questionnaires are designed to collect relevant data in the southern middle and northern Jiangsu Province, to establish hypothetical model based on psychological and behavioral factors of foresters entrepreneurial structural equation. AMOS structural equation was used for data fitting, and SPSS was applied to check the reliability and validity of questionnaire data. [Result] Based on statistical tests, we may find out the results as: reference dependence shows a significant positive effect on entrepreneurial attitude; entrepreneurial attitude has a significant positive impact on entrepreneurial intention; the diminishing sensitivity has a significant positive impact on entrepreneurial intention; loss aversion has a significant positive impact on entrepreneurial intention; entrepreneurial intention has a significant positive effect on entrepreneurial behavior; entrepreneurial attitude has a significant positive effect on entrepreneurial behavior; critical path of the model: reference depend → entrepreneurial attitude → entrepreneurial intention → entrepreneurial behavior.[Conclusion] Reference dependence affects the entrepreneurial attitude, entrepreneurial intention and entrepreneurial behavior. In order to obtain the key psychological factors, it is important not only to pay attention to entrepreneurial attitudes and entrepreneurial intention, but also to pay attention to reference dependencies. Reference dependence shows that the majority of judgment relies on the gains and losses from the reference point. To decide the farmers’ entrepreneurial success and failure, it depends on the comparison of profit of others and their own, which is used as reference decisions affecting the farmers favor of their entrepreneurship. The more entrepreneurial farmers are recognized, the stronger that farmers feel to be as successful entrepreneurs. The entrepreneurs are looking forward to testing their creativity and ideas to enhance the status and prestige. The more likely it is prepared to venture, the more it is mentally prepared to participate in entrepreneurship training, with experience accumulation during entrepreneurship. The entrepreneurs may even plan to have many times of entrepreneurship, and thus focus on the practice and even have influence on others entrepreneurial venture.
Research Progress in Bioremediation of Heavy-Metal Contaminated Soil
Liu Shaowen, Jiao Ruzhen, Dong Yuhong, Liu Caixia
2017, 53(5):  146-155.  doi:10.11707/j.1001-7488.20170517
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In recent years, the heavy metal pollution of soil is becoming more and more serious, it has been a serious problem to human health and social development. At the same time, the remediation techniques also are developed rapidly, especially the development of bioremediation technologies, providing an efficient, eco-friendly way to solve this problem. This paper provides a brief introduction to the characteristics and present situation of heavy metals contaminated soils in China, and comparisons of the traditional physical and chemical remediation techniques with the bioremediation technologies, features and developments of bioremediation, especially in phytoremediation and micro-remediation were reviewed, in order to give a basis for other studies in this area.Recently, with an overall and systematic view, bioremediation through systematic biology, metagenomics and transgenic techniques were introduced to solve the unsteady problem for bioremediation under different conditions. In terms of phytoremediation, studies were mainly focused on transgenic plants, cell engineering technology to strengthen phytoremediation, develop crop plants for phytoremediation. Micro-remediation was focused on screening new microorganisms and plant-microorganism combined bioremediations.The development of bioremediation faces many problems, first of all, most current studies are still in laboratory and small-scale stages, large-scale studies are rare, although some remediation techniques worked well in the laboratory, when applied to engineering practice, the environment factors becoming complicated and uncontrollable, a series of problems would be happening. Secondly, it is hard to repair severe heavy metal pollution only using bioremediation, as bioremediation is based on the metabolic activity of cells, every creature has a certain range of tolerance to heavy metal, beyond the range, the effect of bioremediation will be greatly reduced; Finally, the instability of bioremediation is also a big problem which limits its large-scale application.the solutions for those problems can be summarized in four aspects: 1) Cultivating and selecting plants that are highly capable of accumulating of pollutants, screening more suitable microbes, as biological materials for bioremediation. 2) Using advanced bio-technologies to modify biomaterials, such as gene transformation, cell fusion, cell hybridization, and biological mutagenesis, etc. 3) Regarding the bioremediation as a system, through the methods of genomics, proteomics, to understand the metabolic pathway and mechanism, using the method of systems biology and bioinformatics, controlling the bioremediation process, improving the stability of bioremediation. 4) Application of the new technologies and new methods. In this field, new technologies and methods were often found; people should combine bioremediation with that, in order to increase the efficiency of restoration. 5) Development of associated remediation. Because every remediation technique has its limitations, in practice, the best way to remediate must be associated with methods.
Effect of Management Practices on Methane Uptake in Forest Soils
Wang Huilai, Liu Juan, Jiang Peikun, Zhou Guomo, Li Yongfu, Wu Jiasen
2017, 53(5):  156-163.  doi:10.11707/j.1001-7488.20170518
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Forest soils are the main sinks of atmospheric CH4. This study is aimed to provide a basis for forest management practices under climate change. The databases of Scopus, Web of Science, SDOS and China National Knowledge Infrastructure (CNKI) were used to review current status of studies on CH4 uptake from forest soils. The review highlighted the effect of forest management practices (fertilization, cutting, burning, and understory management) on soil CH4 uptake, and explained its main mechanism. Fertilization tended to inhibit soil CH4 uptake in N-rich forest soils, but obviously promoted soil CH4 uptake in N-poor forest soils. It was generally believed that slash burning reduced soil CH4 uptake. Clear-cutting changed soil temperature, water content, decomposition of organic carbon, and thus weakened the capability of methanotrophs to oxidize methane. Selective-cutting could stimulate, suppress, or show no effect on forest soil CH4 uptake. Understory removal increased soil temperature, sped up evaporation of soil water and increased the activity of methanotrophs, which promoted soil CH4 uptake. Nitrogen fixing plants reduced soil CH4 uptake. There were significant differences of management practices on forest soil CH4uptake among the previous studies. Additionally, the inherent mechanism is still not sufficient. With the development of research theory and technology, the interactive effects of various factors and climate change on forest soil CH4 uptake and its mechanism, the response model of methanotrophs to various interference factors will become the main direction in the future.

The Effects of Continuous Cropping on Major Nutrient Elements and C/N/P Stoichiometric Ratios of Leaf of Populus×euramericana ‘Neva’
Li Kun, Li Chuanrong, Yang Huanxiang, Liang Qiang, Liu Lili, Zhang Caihong
2017, 53(5):  164-169.  doi:10.11707/j.1001-7488.20170519
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[Objective]The objective of this study was to provide theoretical basis for reasonable management of Populus×euramericana ‘Neva’ plantations under different continuous cropping conditions. [Method]An Populus×euramericana ‘Neva’ plantation along Dawen River area was studied. The contents of major nutrient elements in leaves were measured. The variations of stoichiometric ratios and nutrient recovery under different continuous cropping conditions were analyzed. [Result]P and K contents in mature leaves of third generation plantation were significantly lower than those of first and second generations (P<0.05), while the content differences were not significant between the first and second generations (P>0.05), respectively. The effect of continuous cropping on N content was minor. Meanwhile, N, P, and K contents in leaf litters increased due to continuous cropping, especially for those in the third generation plantation. As a result, the recovery rates of N, P, and K in the third generation were significantly lower than those in the first and the second generations (P<0.05), respectively. Moreover, the recovery rate of K was significantly higher than those of N and P (P<0.05), respectively. The stoichiometric ratios of C/N, C/P, and N/P in leaf litters were generally higher than those in mature leaves, respectively. The ratios of N/P and C/P in mature leaves of the third-generation plantation were obviously higher than those of the first and the second generations, however, there were no significant differences among C/N ratios in mature leaves of three generation plantations. With the increase of continuous cropping generations, no obvious variation trend was observed on stoichiometric ratios of C, N, and P in leaf litters. The ratios of N/P and C/P in leaf litters of the first generation were significantly higher than those of the second and the third generations (P<0.05), respectively, while the C/N ratio of the second generation was significantly higher than those of the first and the third generations (P<0.05).[Conclusion]Overall, continuous cropping could reduce the contents of P and K in mature leaves, increase N, P, and K contents in leaf litters, and reduce the nutrient recovery ratio of Populus×euramericana ‘Neva’. The internal circle of nutrients was therefore influenced. In addition, continuous cropping could reduce the decomposition rate of litters and affect the variations of C, N, and P contents in the soil by reducing N/P and C/P ratios in leaf litters.
Theory and Method of Tree Stem Strength Analysis Under Wind Disaster and Its Application
Shao Zhuoping, Wu Yijun, Huang Tianlai, Wang Fuli
2017, 53(5):  170-178.  doi:10.11707/j.1001-7488.20170520
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[Objective] The theory and method of tree stem strength analysis under wind disaster is studied. The strongest wind that tree could resist is predicted by building the relationship between tree stem strain and square of wind speed. [Method] A new method to measure the combined deformation of tree stem was designed: two strain meters were attached to the stem in orthogonal direction, and another two strain meters were attached to the trunk in the ”X“ pattern with 45° and -45°, then the maximum bending linear strain(stress) and maximum torsional shearing strain(stress) caused by combined deformation of bending and torsion of tree stem can be measured. The maximum strain(stress) had no direct relation to wind direction. [Result] Four spicy camphor trees(Cinnamomum camphora) were selected to perform pulling tests under measurable load to verify the new method, and the results indicated that the measured maximum strain only depended on the output values of the sensors and in no relation with the direction of load. Moreover, the stress transformed by Hooke’s law coincided with the theoretical results. Practical test was carried out on a spicy camphor tree in Hefei, China by combining the technique with anemograph under strong wind. The relationship between tree stem strain and square of wind speed was established, due to which the critical wind speed when tree fractured and the failure mode were predicted, and they conformed to the actual situation.[Conclusion] The tree stem strength analysis method proposed here could be applied to measure and analyze the strain(stress) of tree stem subjected to bending and torsion combined deformation under wind load, and predict the maximum wind speed that tree could bear. As crown area, ventilation rate, height of crown center and eccentric distance of crown and some other parameters that difficult to measure did not need to estimate, the new tree stem strength analysis method could provide forest and city garden trees a direct and effective method to assess the resist ability to wind disaster.