2019 Vol. 36, No. 5

Mapping tea gardens spatial distribution in northwestern Zhejiang Province using multi-temporal Sentinel-2 imagery
LI Longwei, LI Nan, LU Dengsheng
2019, 36(5): 841-848. doi: 10.11833/j.issn.2095-0756.2019.05.001
[Abstract](2202) [HTML] (669) [PDF](140)
To develop a new method for accurately mapping the spatial distribution of tea gardens using Sentinel-2 remote sensing imagery, a new approach to the mapping of tea garden resources in Anji of northwestern Zhejiang Province was produced. First, six types of typical vegetation were selected according to a field survey, and their phenological and spectral characteristics were analyzed based on multi-temporal Sentinel imagery. Second, because tea gardens differed from other vegetation types after being pruned in May, a Normalized Tea garden Index (NDTI) was constructed based on the red edge and short-wave infrared bands. Third, a decision tree model based on the new index was used to identify the tea gardens, a total 600 validation points were obtained by field survey, the overall accuracy (OA) and Kappa coefficient were used to evaluate classification accuracy of tea gardens. The accuracy assessment result indicated an overall accuracy of 93.83% and a Kappa coefficient of 0.917. Spatial distribution of the tea gardens was accurately extracted demonstrating the potential to extract tea gardens using the red edge band. The tea gardens was extracted by constructing a normalized tea gardens index, which was easy to understand and realize, and it was easy to operate.
Vegetation classification based on a multi-feature Sentinel-2 time series
GUO Wenting, ZHANG Xiaoli
2019, 36(5): 849-856. doi: 10.11833/j.issn.2095-0756.2019.05.002
[Abstract](3793) [HTML] (1015) [PDF](155)
To provide a statistical basis for biological characteristics, ecological characteristics, and management value of different woodlands, and to provide effective data support for rational management of forests, a forest resources survey was conducted. Vegetation classification, using a hierarchical classification, was the basis for studying the status and dynamics of forest resources with vegetation types being identified quickly and accurately by means of remote sensing. The investigated site was Wangye Forest Farm in southwest Harqin Banner, Inner Mongolia. First, according to the phenological characteristics of the vegetation, images of vigorously growing vegetation were selected to calculate an NDVI and to set appropriate thresholds to extract the vegetation. Then using the NDVI time series, spectral reflectance characteristics of 10 bands in the best time of the Sentinel-2 data as well as textural features of the first three components from a principal component analysis were selected as classification features. The vegetation types in the study area were divided into the five categories of cultivated land, grassland, evergreen coniferous forest, deciduous coniferous forest, and deciduous broadleaf forest using a support vector machine classifier. Classification results were compared with the maximum likelihood method and the method of combining NDVI time series and spectral characteristics. Results showed that the overall accuracy of vegetation classification based on Sentinel-2 time series multi-features reached 87.64%. This was an increase of 15.73% compared to the maximum likelihood method and an increase of 14.61% compared to the method of combining NDVI time series and spectral characteristics. The Kappa coefficient was 0.85, which was an increase of 0.20 compared to the maximum likelihood method and an increase of 0.18 compared to the method of combining NDVI time series and spectral characteristics. Classification accuracy for the evergreen coniferous forest (95.65%) and cultivated land (92.31%) were highly consistent with the field survey. Thus, (1) combining multiple features was helpful for improving classification accuracy; (2) temporal characteristics of NDVI greatly helped to distinguish vegetation; and (3) by using the idea of stratified classification, the vegetation could be extracted first, thereby eliminating the disturbance of non-vegetation factors and effectively improving the classification precision of vegetation types.
Precise identification of forest land types based on high resolution remotely sensed imagery
ZHANG Zhaopeng, LI Zengyuan, TIAN Xin
2019, 36(5): 857-867. doi: 10.11833/j.issn.2095-0756.2019.05.003
[Abstract](2951) [HTML] (763) [PDF](116)
To compare classification methods of forest land types based on high spatial resolution and remote sensing image data in forested areas, Genhe Ecological Station, Genhe City, Inner Mongolia Autonomous Region was selected and red-edge band satellite data was used. With the RapidEye and GF-1 remote sensing images as the main data source, a comprehensive use of imaged spectral features, textural features, forest resources data, and other auxiliary information, as well as the forest land type field survey sample data in 2016, were compared. The ImageSVM, an Interactive Data Language (IDL) based tool for the support vector machine (SVM) classification, ImageRF, an IDL based tool for the random forest (RF) classification, and traditional classifications, like Maximum Likelihood Classification (MLC) and SVM, were used to precisely classify forest land types. Finally, results of a field survey and forest resources data were used as test samples to verify the classification results with precision verification. Results showed that ImageRF and ImageSVM had high precision for forest type information extraction. With RapidEye image, the overall classification accuracy of eight species types such as coniferous forest, broad-leaved forest and shrubbery were 90.26% and 90.02% respectively with a Kappa coefficient greater than 0.88. At the same time, the protraction accuracy and user precision of shrubbery, coniferous forest, and broadleaf forest in ImageSVM and ImageRF were higher than SVM and MLC. The overall classification accuracy with the ImageSVM method was higher than SVM and MLC classification increased 6.18% and 7.06% respectively, and the Kappa coefficient increased 0.07 with SVM and 0.08 with MLC. The ImageRF method improved 5.93% on SVM and 6.82% on MLC, and the Kappa coefficient increased by 0.07 for SVM and 0.08 for MLC. Also, for fine identification of forest land types, the RapidEye image carrying red-edge band information had better recognition precision and separation ability than Landsat 8 OLI images with no red edge band information. Thus, the ImageSVM and the ImageRF classification methods were effective approaches for precise classification of forest land types, fine identification of forest types, and accurate monitoring of forest resources, especially in mountainous areas with complicated topographic conditions, and could fully meet the needs of forestry applications such as forest resources investigation, forest land change monitoring, and thematic map digital update.
Leaf equivalent water thickness estimation based on spectral moisture indexes in broadleaf species
ZHAO Jingyao, ZHANG Xuexia, YANG Wei
2019, 36(5): 868-876. doi: 10.11833/j.issn.2095-0756.2019.05.004
[Abstract](2133) [HTML] (608) [PDF](52)
To quickly and accurately obtain the leaf water content of plants, an important evaluation indicator for evaluating the plant water status, a sensitivity analysis with the PROSPECT Model was performed using the traditional sensitivity analysis method and the EFAST (Extended Fourier Amplitude Sensitivity Test) method. Then, the spectral water indexes with a high sensitivity were selected. Using 8 deciduous broadleaf tree species as the research samples, 1 494 spectral data as input data, an equivalent water thickness estimation model was established and validated based on the ground equivalent water thickness and spectral data. Results showed that EFAST was more sensitive than the traditional sensitivity analysis method in quantifying characteristics of various biochemical parameters. The sensitive wavelength of leaf equivalent water thickness (lEWT) was in the range of 900-2 500 nm, but in the same range, spectral reflectance was also affected by leaf structure and dry matter content. Among the eight spectral water indexes selected, moisture stress index (IMSI), normalized difference infrared index (INDⅡ), and normalized difference water index (INDWI1640) effectively increased sensitivity to lEWT. Validation results based on measured data showed that prediction accuracy of INDWI1640 and INDⅡ estimation models were better than other indexes. Therefore, among the spectral water indexes selected for this study, INDWI1640 and INDⅡ were the best indexes for estimating leaf equivalent water thickness at the scale of the plant leaf; whereas, normalized difference water index (INDWI1240) and simple ratio water index (ISRWI) were suitable for inversion of leaf equivalent water thickness in the areas with lower moisture. The research demonstrated that EFAST method has significant value in guiding modification for localization of model parameters.
Modeling a single-tree biomass equation by seemingly unrelated regression and dummy variables with Larix kaempferi
SHEN Jiapeng, CHEN Dongsheng, SUN Xiaomei, ZHANG Shougong
2019, 36(5): 877-885. doi: 10.11833/j.issn.2095-0756.2019.05.005
[Abstract](2413) [HTML] (661) [PDF](43)
Developing generalized single-tree biomass models suitable for forest biomass estimation is an effective way to provide scientific approaches. To simplify biomass modeling and improve the accuracy of model estimation for better understanding of biomass, carbon stocks, and dynamics in large-scale forests and to precisely estimate tree biomass, this study used stem, bark, needle, branch, and root biomass of Larix kaempferi of 161 sample trees in Gansu, Hubei, and Liaoning Provinces to generalize single-tree biomass equations suitable for different organs and regions using seemingly unrelated regression and dummy variable modeling methods. Results showed that the generalized biomass equations not only solved compatibility problems with different components but also increased accuracy with an average increase of 0.28%-0.44% in R2, decreased 0.40%-6.61% in the root mean square error (ERMS), and decreased 1.63%-6.61% in the mean abosolute bias (BMA). Effects due to region increased accuracy more than effects due to developmental stages. When both region and developmental stages were added to the dummy variable model, it was more accurate and produced the best equation. Therefore, we suggest that both regional and developmental stages be considered as dummy variables to establish generalized biomass equations in order to solve the compatibility problem with different components as well as for overcoming problems of generalizing with different regions.
Initial effects of close-to-nature thinning on a natural secondary Pinus massoniana pure forest in central Guizhou
WANG Ke, TAN Wei, QI Yujiao
2019, 36(5): 886-893. doi: 10.11833/j.issn.2095-0756.2019.05.006
[Abstract](1991) [HTML] (566) [PDF](52)
In 2013, close-to-nature thinning was implemented in two, age-grade Pinus massoniana natural secondary pure forests in the middle of Guizhou Province. To evaluate the growth initial effects of the close-to-nature thinned forests for 4 years and to provide references for sustainable forest management of Guizhou Province, through the investigation of the diameter of breast height(DBH), tree height, volume, accumulated and understory vegetation of 8 fixed plots and 8 temporary plots (100-400 m2), compare the difference between the growth of thinned forests and control stands. Results showed that:(1) Thinning was conducive to the production of large-diameter timber. For middle-aged forests and near-mature forests, the ratio of the number of plants with DBH of 8-14 cm and 10-14 cm for the control medium was largest. Whereas, with DBH of 12-18 cm and 22-26 cm, the thinned medium was largest. (2) Thinning promoted growth of DBH and volume of the trees. The annual growth of DBH and volume of the average tree, target tree, and non-target tree in the thinning reached 1.15 times higher of the control, and the highest in the target tree of the middle-aged forest reached 1.65 times of the control. (3) Thinning increased the accumulated growth rate of the stands. In thinned stands, the accumulated growth was less than the control stands, but the accumulated growth rate was higher than the control stands in the middle (by 4.13%) and near mature forests (by 1.03%). (4) The effect of thinning on height growth and the growth of understory vegetation was not obvious, the growth factors of tree height and understory vegetation did not show significant differences in thinning and control stands (P>0.05).
Heat and drought stress with an antioxidant defense system in Heimia myrtifolia
GU Fan, JI Mengcheng, GU Cuihua, ZHENG Gang, ZHENG Shaoyu
2019, 36(5): 894-901. doi: 10.11833/j.issn.2095-0756.2019.05.007
[Abstract](2164) [HTML] (506) [PDF](52)
To determine the effects of drought stress and heat stress both individually and combined on the antioxidant defense system of Heimia myrtifolia, an introduced plant with high value but poor distribution. Soil moisture loss with natural high temperature and drought conditions without replenishment were artificially simulated using drought stress of a control (no stress), light, moderate, and heavy stresses and heat stress of 30℃ (control), 36℃, and 42℃. The upper complete functional leaf was carried out when the moisture gradient reaches the sampling requirement under heat treatment. Experimental results showed that, firstly, with drought treatments, peroxidase (POD) activity and malondialdehyde (MDA) molar concentration increased significantly (P < 0.05), lipid membrane peroxidation deepened, ascorbic Acid-glutathione (AsA-GSH) cyclerelated enzyme activity and related reductants increased first and then decreased, peaking with moderate stress and significantly increased compared with the control (P < 0.05). Secondly, with high temperature stress, the efficiency of antioxidant enzymes and ASA-GSH cycle increased but not dramatic. Finally, with the synergistic stress of heat and drought, the damage of H. myrtifolia was significantly greater than that with single stress. The superoxide dismutase (SOD) and POD activities increased significantly (P < 0.05) and reached the peak with moderate stress. The molar concentration of MDA increased significantly (P < 0.05). The circulation efficiency of AsA-GSH increased, but began to decrease with moderate stress. Lipid membrane peroxidation increased significantly with the deepening of stress and the normal growth could not be maintained with severe stress. Thus, with heat and drought stress, the plant could remove excessive reactive oxygen by regulating the antioxidant enzyme system and AsA-GSH cycle, and improve resistance to stress so as to maintain normal growth and development.
Soil cover with rhizome controlling cultivation of nutrients and physiological resistance for a Phyllostachys prominens rhizome system
SHI Junshuai, ZHANG Chao, CHEN Shuanglin, GU Rui, GUO Ziwu
2019, 36(5): 902-907. doi: 10.11833/j.issn.2095-0756.2019.05.008
[Abstract](2169) [HTML] (512) [PDF](38)
The aim is to approach the effect of soil cover with rhizome controlling cultivation on nutrients and physiological resistance of rhizome roots from Phyllostachys prominens as well as to determine the optimum soil cover thickness for high-quality root and rhizome system. The content of carbon (C), nitrogen (N), and phosphorus (P) as well as physiological indexes of rhizome roots from P. prominens with different soil cover thickness[0(ck), 10, 30, and 50 cm] were determined, and each index was measured three times. Meanwhile, the saliency test was also carried out. Results showed that compared with ck, soil covering management with moderate thicknesses (≤ 30 cm) influenced content of N, malondialdehyde (MDA), superoxide dismutase (SOD), peroxidase (POD), soluble protein, soluble sugar, and root activity significantly (P < 0.05), but the content of C, P, C/P, N/P, and relative electrical conductivity of those treatment changed slightly(P>0.05). With soil covering thickness increaseing, content of N, MDA, soluble protein, SOD, POD, and N/C of root and rhizome systems tended to decrease first and then increase (P < 0.05), but soluble sugar and root activity changed in an opposite trends (P < 0.05). Thus, moderate thickness of soil covering (10 and 30 cm) could improve the growth environment conditions of root and rhizome systems to some extent, and promote growth of P. prominens, but excess thickness of soil covering would have a negative impact on root and rhizome systems. All results indicated the suitable soil covering thickness for better bamboo shoot quality, economic yield benefits, and bamboo forest sustainable management of P. prominens should be 30 cm.
Leaf growth, chlorophyll fluorescence characteristics, and expression of photosystem-related genes in Camptotheca acuminata with different N forms'fertilization
BIAN Sainan, CHANG Pengjie, WANG Ninghang, LIU Zhigao, ZHANG Mingru, WU Jiasheng, SHEN Yamei, WANG Xiaode
2019, 36(5): 908-916. doi: 10.11833/j.issn.2095-0756.2019.05.009
[Abstract](2495) [HTML] (551) [PDF](47)
To provide a theoretical basis for fertilizer cultivation of Camptotheca acuminata and to explore the optimum nitrogen (N) level and suitable N form for growth, two-year-old C. acuminata was used as the material with pure ammonium sulfate[(NH4)2SO4] and potassium nitrate (KNO3) for fertilization by using pot-cultivated experiments. The control (ck-no fertilizer), and four different concentrations of both ammonium nitrogen (NH4+-N)[T1(2.5 g·tree-1), T2(5.0 g·tree-1), T3(7.5 g·tree-1), and T4(10.0 g·tree-1)] and nitrate N(NO3--N)[W1(2.5 g·tree-1), W2(5.0 g·tree-1), W3(7.5 g·tree-1), and W4(10.0 g·tree-1)] were used. The effects of growth physiology, chlorophyll fluorescence parameters, and expression of PS Ⅱ chloroplast-associated genes (psbA, psbB, psbC, and RbcL) were studied. Results showed that compared with no fertilizer, all C. acuminata plants with all ammonium N and nitrate N fertilization treatments promoted (P < 0.05) growth, chlorophyll synthesis, chlorophyll fluorescence characteristics, and chloroplast-related gene expression. Both T3 and W3 fertilization treatments had the best effect (P < 0.05), W3 was better than T3 in the growth(P < 0.05) and C. acuminata can be considered as a nitrophilous plant Chlorophyll fluorescence was significantly inhibited P < 0.05) with T4 and W4 treatments. Thus, excessive N fertilizer was not conducive to improvement of the photosynthetic ability in plants. The growth and photosynthetic efficiency of C. acuminata can be improved by increasing ammonium nitrogen and nitrate nitrogen. Both ammonium nitrogen and nitrate nitrogen had the best growth effect at 7.5 g·tree-1.
Cloning and characterization of a long terminal repeat retrotransposon (Phyllostachys edulis retrotransposon 7) in Phyllostachys edulis
JIANG Zhengqin, ZHOU Mingbing, ZHENG Hao, JI Hang, XU Zhixin
2019, 36(5): 917-927. doi: 10.11833/j.issn.2095-0756.2019.05.010
[Abstract](2401) [HTML] (600) [PDF](32)
Long terminal repeats (LTR) retrotransposons, a type of mobile DNA sequence widely found in plant genomes, could be activated and transposed in response to changes in the environment. To study the transcriptional activity of LTR retrotransposons in the genome of Phyllostachys edulis and to determine the specific changes of their expression under abiotic stress, an LTR retrotransposon in Phyllostachys edulis (PHRE 7) was cloned and characterized. The total length of the transposon was 6 073 bp, belonging to the Tork branch in the Ty1-copia family. The homology of the LTR sequence was 96.7% with an insertion time of about 1.269 million years ago. The experiment had five different treatments including irradiation (30, 50, and 70 Gy), methylation inhibitor (50, 100, and 150 μmol·L-1), high temperature (42℃), low temperature (4℃) and salt stress (0.1, 0.2, and 0.3 mol·L-1) on Phyllostachys edulis seedlings. Real-time fluorescence quantitative PCR was used for the analysis of relative expression of transposon domains including RT (Reverse Transcriptase) protein domain, RH (Ribonuclease H) protein domain and INT (Integrase) protein domain in PHRE7. Results detected by real-time fluorescence quantitative PCR showed that under the conditions of low/high temperature, methylation inhibitors and the salt concentration (0.1-0.2 mol·L-1), the expression level of three domains (INT, RT, RH) of PHRE 7 were increased and the expression level under irradiation dose and the salt concentration (0.2-0.3 mol·L-1) were decreased. Thus, the PHRE 7 transposon was a transcriptionally active LTR retrotransposon, and the abiotic environmental stress had a great influence on its expression pattern indicating that the PHRE 7 transposon could respond to external environmental changes; however, the specific response mechanism, not yet being clear, means further research and analysis are still needed.
Screening reference genes of Osmanthus fragrans with differing photoperiod and temperature treatments
WANG Qianqian, JIANG Qini, FU Jianxin, DONG Bin, ZHAO Hongbo
2019, 36(5): 928-934. doi: 10.11833/j.issn.2095-0756.2019.05.011
[Abstract](2129) [HTML] (671) [PDF](37)
Photoperiod and temperature treatment can affect the gene expression level and flower bud differentiation process of Osmanthus fragrans. Analysis of gene expression by quantitative real-time polymerase chain reaction (qRT-PCR) has become an important means to study the mechanism of these processes and it is especially important to screen for an internal reference gene suitable for photoperiod and temperature treatment. To screen reference genes in O. fragrans using different photoperiod and temperature treatments, the young leaves of O. fragrans 'Foding Zhu' were used as materials. The O. fragrans treatment conditions were 14 h D (light)/10 h N (dark) +26℃, 14 h D/10 h N +19℃, 10 h D/14 h N +26℃ and 10 h D/14 h N +19℃, light intensity 100%, relative humidity 60%-80%. After treatment for 40 days, the second or third young leaves of the current shoots were taken every 4 h from 8:00 in the morning frozen in the liquid nitrogen and stored at -80℃. The seven genes, including OfACT, OfEF1α, OfIDH, OfRAN1, OfTUB, OfUBC2, and Of18S, were chosen as candidate reference genes. qRT-PCR was used to screen the reference genes, and GeNorm, NormFinder, and BestKeeper were used to analyze the stability of the candidate reference genes and screen out the best ones. Finally, the circadian rhythm gene GIGANTEA (GI) was used to verify the best reference genes. Results showed that OfRAN1 and OfIDH had the highest stability(GeNorm showed that the stable value of OfRAN1 and OfIDH were 0.347, while Of18S was 0.601; NormFinder showed that the stable value of OfRAN1 and OfIDH were 0.135 and 0.206, while Of18S was 0.474; BestKeeper showed that the stable value of OfRAN1 was 0.800 and OfIDH was 0.133, while Of18S was 0.474), which meant they were the best reference genes for the different conditions and Of18S had the worst stability(The greater the stability value, the worse the stability). The relative expression level of GI balanced by seven reference genes and the genetic combinations of OfRAN1 and OfIDH meant more accurate expression results(The expression pattern of circadian rhythm gene GI is accumulated during the day and falls at night). In summary, the genetic combinations of OfRAN1 and OfIDH were the best combination of reference genes used to study the molecular mechanism of O. fragrans under different photoperiod and temperature treatments.
Reference genes for quantitative PCR in Magnolia sinostellata with heat stress
WANG Qianying, CHANG Pengjie, SHEN Yamei, ZHANG Chao, DONG Bin, SHI Baozhu
2019, 36(5): 935-942. doi: 10.11833/j.issn.2095-0756.2019.05.012
[Abstract](1887) [HTML] (566) [PDF](23)
In field investigation high temperature was found to have a serious effect on growth of Magnolia sinostellata, an endemic endangered species in Zhejiang. To determine if screening stable reference genes of M. sinostellata with heat stress could provide accurate data for research in gene expression and achieve accurate quantification of target genes, roots, stems, and leaf tissues from annual seedlings of M. sinostellata with heat stress were taken as materials. Expression stability of 13 reference genes from transcriptome data, such as ACTIN-7 (ACTIN-7), CYP (Cyclophilin), EF-1α (Elongation factors-1α), GAPDH (Glyceraldehyde-3-phosphate dehydrogenase), GBP (GTP binding protein), NAC (NAC domain protein), NADP (NADP-isocitrate dehydrogenase), TEF (Translation elongation factors), UBC (Ubiquitin-conjugating enzyme), UBQ (Polyubiquitin protein), α-TUB (Tubulin alpha), β-TUB (Tubulin beta), and 18S (18S ribosomal RNA) were detected and evaluated by quantitative reverse transcriptase (qRT)-polymerase chain reaction (PCR) along with geNorm, NormFinder, and BestKeeper. Also, two target genes, CSLD3 and KOR, were analyzed to verify reliability of the screened reference genes. Specificity of the 13 pairs of primers was validated with agarose gel electrophoresis and a melting curve. Results showed that the 13 reference genes had a distinct PCR product in the electrophoresis figure, and the melting curve showed a single peak. Amplification efficiency of the 13 pairs of primers was about 100% with UBC, EF-1α, and ACTIN-7 being stable reference genes in different tissues of M. sinostellata. Additionally, the two target genes, CSLD3 and KOR, showed consistent expression profiles when normalized by UBC, EF-1α, and ACTIN-7, as well as the combination (EF-1α and ACTIN-7). UBC, EF-1α, and ACTIN-7 were the best choices in different tissues of M. sinostellata with heat stress, and since expression analysis of the target genes, CSLD3 and KOR, further confirmed reliability of these genes, UBC, EF-1α, and ACTIN-7 could serve as references genes for expression among different tissues in M. sinostellata with heat stress.
Cloning and expression analysis of CHS gene family in Citrus suavissima 'Seedless'
YU Dihu, ZHANG Chi, KE Fuzhi, JING Luyang, GU Xuejiao, WU Baoyu, ZHANG Min
2019, 36(5): 943-949. doi: 10.11833/j.issn.2095-0756.2019.05.013
[Abstract](2577) [HTML] (562) [PDF](35)
Citrus suavissima 'seedless' (Wuzi Ougan), a bud variant of C. suavissima (Ougan), maintaining almost all excellent characteristics of 'Ougan' except for seedlessness, and chalcone synthase (CHS), playing an important role on plants by providing floral organs with different types of flavones, were used in this study. To indicate the role of the CHS gene family in male sterility in Wuzi Ougan, four CHS homologs were differentially expressed in a comparative analysis of transcriptome and proteome between Wuzi Ougan and Ougan. The CHS homologs in Wuzi Ougan and Ougan were isolated and their expressions were individually analyzed in different developmental stages of anthers and floral organs. Then, a bioinformatics analysis of the CHS gene family was carried out based on the clementine mandarin genome. Results showed that the nucleotide sequences of CHS homologs derived from Wuzi Ougan and Ougan shared more than 98% similarity with their homologs in clementine mandarin. Real-time polymerase chain reaction (PCR) showed that Ciclev10005133m, Ciclev10030093m, and Ciclev10015535m were down-regulated at microsporcyte in Wuzi Ougan; whereas, Ciclev10005133m, Ciclev10001405m, and Ciclev10015535m were down-regulated in Wuzi Ougan at meiosis. In terms of tetrad, Ciclev10030093m and Ciclev10001405m were down-regulated in Wuzi Ougan (P < 0.05). After pollen maturation, Ciclev10001405m and Ciclev10005133m were mainly expressed at anthers (P < 0.05). The bioinformatics analysis revealed 13 CHS genes that were identified in clementine mandarin. In conclusion, members of the CHS family maintained high similarity in coding sequence (CDS) and were differentially expressed between Wuzi Ougan and Ougan in anther development, which was expected to contribute to male sterility in Wuzi Ougan.
Characteristics and diagnosis of nitrogen nutrition for rice canopy leaf SPAD value changes
YU Minyi, YU Kaikai, FEI Cong, KE Weiyu, WU Yefei, ZHANG Zhenzi, BAO Zehang, LIN Haichen, LI Feifei, CHEN Guolin, LÜ Zunfu
2019, 36(5): 950-956. doi: 10.11833/j.issn.2095-0756.2019.05.014
[Abstract](1660) [HTML] (428) [PDF](25)
Nitrogen(N) is important for rice growth. To establish a rice (Oryza sativa) nitrogen nutrition diagnostic model that could reflect the N status of a rice organism and that could be convenient for rice field management, a rice community test was conducted in Deqing City, Zhejiang Province in 2015. Oryza sativa 'Yongyou 538' and 'Xiushui 134' were taken as the representative cultivars. Five levels of N were established:0(N0)(ck), 70.0(N1), 140.0(N2), 210.0(N3), and 280.0(N4) kg·hm-2. Measurement of rice SPAD (soil and plant analyzer development) values were made using a portable SPAD-502 meter and followed by a correlation analysis. Results showed that the fourth leaf from the top was a good indication of plant nutrition status. There was a significant positive correlation between the normalized SPAD index (INDSPAD14) and N content in canopy leaves with the N0-N4 treatments. The coefficients of determination for 'Yongyou 358' r2=0.69-0.96 and for 'Xiushui 134' r2=0.64-0.94. By analyzing the relationship between INDSPAD14 and plant N content, a diagnostic model of rice N concentration was established.
Relationship between shrubs and soil nutrients in Wuhai City
TAN Jin, YANG Jianying, HOU Jian
2019, 36(5): 957-964. doi: 10.11833/j.issn.2095-0756.2019.05.015
[Abstract](3216) [HTML] (568) [PDF](20)
In Wuhai, the environment was destroyed because of its own defects and the exploitation of many mining areas. Therefore, it is very necessary for the region to carry out targeted environmental governance, and the selections of plant species are very important for environmental governance. Soil is indispensable for plant growth. Understanding the spatial pattern relationships between different species and different soil resources is of great reference value for the preliminary selections of plant species, and can also provide very important information for the land managers. In order to achieve these objectives, a classical statistical method-spatial point pattern analysis-was used in this study. It can reflect the correlation and obtain relative scale of research objects. Nine communities were selected according to different vegetation groups in the surrounding area of Wuhai. Three plots of shrubs and three plots of herbage were selected from each group for investigation, and the most statistically significant plot was selected according to the principle of spatial point pattern analysis from the three shrubs plots which have investigated already. Soil samples were collected with the origin of a square coordinateaxis as the reference point. Every soil sample was separated from the other samples by 100 cm, a 0-20 cm soil sample of 1.0 kg was taken, and the specific coordinates of each shrub were determined and recorded. After determining the contents of total nitrogen (TN), total phosphorus (TP) and soil organic matter (SOM) of soil samples, The coordinates with the highest nutrient content of 20% of each resource and the coordinates of Caragana spp. or Artemisia desertorum were calculated by spatial point pattern analysis. Then an aggregated relationship and a relative scale were obtained. Results showed that in the steppe desert of Wuhai, there were aggregated relationships between TN and Caragana spp. or Artemisia desertorum. The relative scale was C. stenophylla (250 cm) > C. sinica (230 cm) > C. korshinskii (150 cm) > A. desertorum (100 cm) > A. desertorumina plot with A. desertorum + Nitraria tangutorum (75 cm). For the C. sinica aggregate with TP, the relative scale was 50 cm, and for the A. desertorum aggregate with SOM, the relative scale was 200 cm. In the desert grassland, the relative scale for C. tibetica aggregate with SOM was 45 cm, and the A. desertorum aggregate with SOM was 190 cm. The relative scale obtained by applying the spatial point pattern analysis to the spatial relationships between shrubs and soil nutrients can reflect the distribution range of roots and crowns of shrubs and reveal the spatial pattern relationship between shrubs and soil nutrients in depth.
Distribution and division of stony desertification on county scale
LIU Peng, WANG Yan, LIU Zongbin, GUO Yujing, ZHANG Zixia, LI Xiangwang, YANG Bo
2019, 36(5): 965-973. doi: 10.11833/j.issn.2095-0756.2019.05.016
[Abstract](3432) [HTML] (843) [PDF](53)
Yunnan is located in the center of rock desertification area in southwest China. It is of great significance to carry out the quantitative analysis of rocky desertification distribution in the whole province, in order to promote the treatment of rocky desertification, ecological environment protection and sustainable development. Dominant factor method and superposition method were used to divide 65 rocky desertification counties in Yunnan, according to the comprehensive factors such as landform, climate, soil and vegetation. Results showed that 65 rocky desertification counties in Yunnan Province could be divided into 7 areas, 10 subregions and 19 districts. 7 areas included North Tropical Low Mountain Valley Basin Rocky Desertification Area, South Subtropical Medium Low Mountain Valley Basin Rocky Desertification Area, Central Asia Subtropical Plateau Mountain Rocky Desertification Area, North Subtropical High-medium Mountain Rocky Desertification Area, Warm Temperate High Medium Rocky Desertification Area, Temperate Rocky Desertification Area on the Southeast of Qinghai-Tibet Plateau, and Jinsha River Dry Hot Desert Valley Rocky Desertification Area. The new system of dividing rocky desertification areas in Yunnan Province proposed in this study is an innovative achievement from the extensive macro division to the intensive division. The results of this division make the technological design of comprehensive treatment of rocky desertification more operational.
Physical and mechanical properties of Phyllostachys edulis with fast hot-pressing and high temperature
MO Jue, MA Zhongqing, NIE Yujing, MA Lingfei
2019, 36(5): 974-980. doi: 10.11833/j.issn.2095-0756.2019.05.017
[Abstract](1961) [HTML] (547) [PDF](22)
To improve dimensional stability and weather resistance of a material, heat treatment, with fast hot-pressing and high temperature, was used. Pieces of 4-6 year-old Phyllostachys edulis were selected. Samples were treated with different temperatures (225, 250, 275, 300, 325, 350, and 375℃). Physical and mechanical properties were tested before and after treatments. Results showed that with an increase of temperature, there was an obvious decrease in equilibrium moisture content (34.39%-53.95%) and bamboo density (7.89%-13.04%) both P < 0.05. With the same conditions, the following occurred:rate of change for tangential shrinkage rate > rate of change for volume shrinkage rate > rate of change for radial shrinkage rate. When the temperature reached 375℃, tangential oven-dry shrinkage rate decreased 86.81%; whereas, radial oven-dry shrinkage rate dropped 83.60%, and volume oven-dry shrinkage rate decreased 83.95%, reaching a maximum in all directions. Compression strength parallel to the grain, modulus of rupture (MOR), and modulus of elasticity (MOE) of the bamboo increased with temperature first and then decreased. Compression strength reached a minimum of 63.78 MPa at 375℃. MOR reached a peak at 250℃ with 151.00 MPa, and decreased to 61.85 MPa at 375℃. MOE performed best at 300℃ with 10 487.44 MPa, and worst at 375℃ with 7 071.14 MPa. Thus, this experiment proved that fast hot-pressing with high temperature can improve the dimensional stability of the bamboo, the mechanical properties also generally improved after treatments.
Pretreatment on characteristics of pyrolysis products for small diameter sympodial bamboo with torrefaction
ZHANG Yu, XU Jiajia, MA Zhongqing, WANG Junhao, LI Wenzhu, ZHANG Wenbiao
2019, 36(5): 981-989. doi: 10.11833/j.issn.2095-0756.2019.05.018
[Abstract](2077) [HTML] (542) [PDF](25)
To determine the effect of torrefaction temperature on the properties of gas, solid, and liquid products from pyrolysis, small diameter cluster bamboo Chimonobambusa quadrangularis was heated to 210, 240, 270, and 300℃ and a pyrolysis temperature of 550℃. Also, a furnace with a programmed temperature control, a thermogravimetric analyzer coupled with fourier-transform infrared spectrometry (TGA-FTIR), and a pyrolyzer coupled with a gas chromatography/mass spectrometer (Py-GC/MS) were utilized. Based on the analysis, the mechanism of pyrolysis for solid products after torrefaction was discussed. The test of the effect of different temperature torrefaction pretreatment on the characteristics of pyrolysis products with bamboo powder as raw material, repeated three times for each test to reduce the error. Experimental results showed that (1) For the solid product after torrefaction with an increase in torrefaction temperature, the content of C and fixed carbon in solid products increased much; oxygen content and volatile matter decreased, and the O/C ratio decreased from 0.72 to 0.53. The calorific value increased from 18.32 MJ·kg-1 to 21.65 MJ·kg-1, and the bamboo energy density strongly improved. (2) For the pyrolysis gas product, the main constituents were in the order CO2 > H2O > CO > CH4 > H2. As the degree of torrefaction deepened, CO2, H2O, CO and CH4 yields in the pyrolysis decreased, and H2 production increased. (3) The liquid products of pyrolysis were mainly composed of organic substances such as acids, phenols, furans, ketones, and aldehydes. The dominant components were acids (12.69%), phenols (34.72%), and furans (29.80%). However, the content of ketones (9.32%) and aldehydes (11.87%) were lower. With the increase in torrefaction temperature, the content of acids, aldehydes, and furans in pyrolysis oil decreased gradually, and the content of phenols and ketones increased gradually. Thus, the upgrading mechanism for gas, solid, and liquid products from the pyrolysis process in conjunction with torrefaction temperatures, provided basic data for energy utilization of cluster bamboo.
Changes in the ecological environment of Wuhai City and driving factors
ZHAO Xungang, HU Yucun, WANG Wenhui, HU Yunqing
2019, 36(5): 990-998. doi: 10.11833/j.issn.2095-0756.2019.05.019
[Abstract](3321) [HTML] (527) [PDF](30)
Western China, as a main production base, was rich in mineral resources; however, due to unrestrained mining, the local ecological environment underwent tremendous changes. So, to deeply understand changes in the ecological environment and driving factors in Western China, Wuhai City was studied with 11 factors(independent variables, x) being selected namely, slope, aspect, curvature, relief amplitude, altitude, vegetation coverage, distance to water sources, distance to roads, population, gross industrial output value, and per capita disposable income of residents. The analytic hierarchy process (AHP) was used to construct an evaluation model of eco-environmental sensitivity, and then we used the geographic detectors model to analyze the main factors affecting the ecological environment changes. We selected the study years (2008, 2013, 2016) which are impacted to Wuhai City. The year which we selected, was used as a sample and the sample size is 2 200. Results showed the ecologically fragile zone extends from the south-central region (607.145 km2) in 2008 to the northern region (1 715.978 km2) in 2013. Up to 2016, restoration of the ecological environment was 46.790 km2 for Haibowan District (9.0% of the partitioned area) and 0.212 km2 for Wuda District (0.1%). Changes in the ecological environment of Wuhai City resulted from combined actions between nature and anthropogenic factors with the distance to water sources (q=0.782, P < 0.05), population number (q=0.708, P < 0.05), gross industrial output value(q=0.499, P < 0.05), and per capita disposable income of residents(q=0.490, P < 0.05) being the main driving factors. Therefore, regulation of the above factors should increase to achieve the best treatment effect.
Coupling relationship between urban land intensive use and ecological civilization construction
ZHU Qianlong, LIU Pengling, LUAN Jingdong, YANG Naiqi
2019, 36(5): 999-1005. doi: 10.11833/j.issn.2095-0756.2019.05.020
[Abstract](3014) [HTML] (633) [PDF](16)
There is an interactive coupling relationship between urban land intensive use and ecological civilization construction. It is important to evaluate the degree of coupling and coordination of urban land use efficiency and urban sustainable development. Taking China's five national-level urban agglomerations including Yangtze River Delta Urban Agglomeration, Pearl River Delta Urban Agglomeration, Beijing-Tianjin-Hebei Urban Agglomeration, Yangtze River Middle Reach Urban Agglomeration and Chengdu-Chongqing Urban Agglomeration as research objects, the weighted TOPSIS model is used to evaluate the comprehensive scores of the intensive use of land and ecological civilization from 2007 to 2016. On the basis of this, the coupling coordination degree model is used to measure the coupling coordination degree and evolution. The study found that the comprehensive scores of land intensive use and ecological civilization construction of the five national-level urban agglomerations had been on the rise from 2007 to 2016, and the differences among urban agglomerations were small; the coupling degree between urban land intensive use and ecological civilization construction changed from moderate disorder to basic coordination, and reached an overall coordination level. The average coupling coordination degrees of urban agglomerations were ranked as follows:Pearl River Delta > Yangtze River Delta > Beijing-Tianjin-Hebei > Yangtze River Middle Reaches > Chengdu-Chongqing. Further strengthening the management of land resources and deepening the comprehensive management of urban ecological environment can promote the coordinated development of land intensive use and ecological civilization construction of urban agglomerations, and promote the construction of a resource-saving and environment-friendly society.
Large rice farmer households'decisions on mechanic service outsourcing in rice production
PENG Yanghe, PAN Weiguang, LI Lin
2019, 36(5): 1006-1011. doi: 10.11833/j.issn.2095-0756.2019.05.021
[Abstract](2463) [HTML] (555) [PDF](29)
Based on the survey data of 148 farmer households in 3 counties of Zhejiang Province, this study constructed a multiple linear regression model to make an empirical analysis of the factors influencing farmer households' decisions on mechanic services outsourcing in Oryza sativa production. The research showed that with the increase in the farming area of rice, farmer households'probability of accepting socialized services would increase first and then decrease, showing an inverted U curve and indicating an obvious economies of scale. Age had a significant positive impact on the degree of accepting mechanic services; whether the family members had experience of operating agricultural machines, the number of agricultural machines owned by the households, and the fragmentation of land had significant negative impacts on the acceptance of mechanic services. Based on our research, we proposed policy recommendations including cultivating multiple service organizations, encouraging land consolidation, and providing a good development environment for mechanic services outsourcing.
Impact of climate change cognition on public willingness to pay for environmental protection and mitigation actions
SHAO Huiting, LUO Jiafeng, FEI Ximin
2019, 36(5): 1012-1018. doi: 10.11833/j.issn.2095-0756.2019.05.022
[Abstract](2340) [HTML] (713) [PDF](26)
Based on Chinese General Social Survey(CGSS) 2010 data, we use Ologit regression model to describe and analyze the influencing factors of public willingness to pay for environmental protection and emission reduction behavior. The empirical results show that the residents' overall willingness to pay for environmental protection and emission reduction are not high. At the same time, the willingness to pay for environmental protection is higher than the willingness to reduce emissions, which indicates that in order to protect the environment, the public is more willing to bear certain losses economically than to take environmental protection actions inconvenient to life. Climate change cognition has a significant positive impact on the willingness to pay for environmental protection and emission reduction behavior, and the impact of climate change cognition on environmental protection willingness is more significant than the emission reduction behavior. In addition, it is also found that income, religious beliefs and regions have a significant impact on the public's willingness to pay for environmental protection; age, education, media use, urban and rural residential areas and areas have significant impact on public emission reduction behavior. According to these conclusions, some suggestions are put forward to improve the public's environmental awareness level by using modern information transmission methods and various opportunities to strengthen publicity, and to adjust the public's behavior choices through fiscal, taxation, credit and subsidies.
Effects of invasive plants on soil microbial communities: a review
PENG Xinyi, LI Yongchun, WANG Xiuling, LI Yongfu, CHEN Zhihao, XU Qiufang
2019, 36(5): 1019-1027. doi: 10.11833/j.issn.2095-0756.2019.05.023
[Abstract](3032) [HTML] (911) [PDF](107)
Invasive plants cause great harm to the social, economic and ecological environment in the invaded areas by affecting soil microbial biomass, microbial community diversity and functional microbiota. Plant species invasion has become a global problem and one of the hotspots of current research. In this paper, we summarized the effects of plant invasion on soil microorganism, and the biological mechanism of the influence of Moso bamboo (Phyllostachys edulis) invasion on soil microorganism characteristics. Studies showed that invasive plants would increase soil microbial biomass and soil microbial diversity to create favorable soil environment for invasive plant species. Invasive plants would change nutrient cycling and other environmental conditions through changing functional groups of soil microorganisms, and in turn promote the process of plant invasion. Enhanced research on the effects of plant invasion on soil microbes and associated nutrient cycling would help clarify the "plant-soil" feedback mechanism, which could provide a basis for the prevention, control and habitat restoration of plant invasion.
Research progress on biological characteristics, occurrence and control of Oryza sativa f. spontanea
WANG Bei, HE Yu, WU Rong, SHEN Yafang, WANG Yang, ZHAO Guangwu
2019, 36(5): 1028-1036. doi: 10.11833/j.issn.2095-0756.2019.05.024
[Abstract](2966) [HTML] (733) [PDF](59)
As a kind of accompanying notorious weed occurring in rice-planting areas, weedy rice (Oryza sativa f. spontanea) is taxonomically classified as the same species as cultivated rice (Oryza sativa), with the characteristics of strong growth potential, easy threshing, strong dormancy and stress tolerance; and it is mainly originated from the domestication of cultivated rice. The occurrence of weedy rice seriously affects the yield of cultivated rice, reduces the quality of rice, affects the purity of rice seeds, and is difficult to control. Weedy rice is distributed unevenly in Guangdong, Liaoning, Ningxia, Jiangsu, Jiangxi, Heilongjiang, Anhui, Shandong and Zhejiang Provinces. The main causes are cross-regional operation of agricultural machinery, changes in cultivation techniques and lack of selective herbicides. At present, artificial extraction, adjustment of cultivation methods (interplanting, direct seeding into transplanting, machine transplanting), the implementation of drought and flood rotation, the application of herbicides such as propyl oxalamide are used to prevent and control weedy rice, but there are no very effective prevention and control measures. However, due to its rich variation types and similar genetic background with cultivated rice, weedy rice can be used as an important germplasm resource for improvement of cultivated rice.
Scientific notes
Variable fruit and seed characteristics of Xanthoceras sorbifolium in different populations
ZHANG Yi, AO Yan, LIU Juefei, ZHAO Leilei, YOU Haide
2019, 36(5): 1037-1043. doi: 10.11833/j.issn.2095-0756.2019.05.025
[Abstract](1796) [HTML] (468) [PDF](25)
To determine the variable patterns of fruit and seed characteristics for Xanthoceras sorbifolium within and among populations, fruits and seeds of 1 044 individuals were collected from seven populations in the main distribution areas. 20 fruits and 50 seeds were selected from each individual by quadruple method to measure 12 fruit and seed characteristics. Analysis of variance, correlation analysis, and cluster analysis were used for the analyses. Results showed that (1) there were highly significant(P < 0.01) differences in fruit and seed characteristics among populations. Relatively high variation coefficients were observed in yield characteristics including seed yield per unit projective area(CV=46.39%)and fruit number(CV=45.32%). However, relatively low variation coefficients occurred in fruit and seed form characteristics including fruit shape index(CV=8.84%)and seed width(CV=11.50%). (2) There were significant variations in fruit and seed characteristics within(Vst=32.14%) and among(Vst=67.86%) populations. Variation in fruit and seed characteristics among populations was greater than that within populations. (3) Moreover, seed yield per unit projective area was highly significant (P < 0.01) and positively correlated with fruit weight (r=0.786), fruit number (r=0.782) and seed number per fruit (r=0.688). There were also highly significant (P < 0.01) and positive correlations between seed oil concentration and seed number per fruit (r=0.765), seed width (r=0.662), fruit width(r=0.627) and fruit length (r=0.541). (4) According to results of a cluster analysis, seven populations were divided into three groups. The Zhudaigou (ZDG) population was superior to other populations in yield characteristics including seed yield per unit projective area(0.13 kg·m-2), seed number per fruit(17.6), fruit number(77.7), and fruit weight(3.67 kg). However, the seed oil concentration(0.35 g·g-1) in Kundu (KD) and Chengde (CD) populations were higher than other populations. Thus, ZDG could be used for high-yield, germplasm resource collection, and KD and CD populations could be used for high-oil, germplasm resource collection.
Response of masson pine container seedlings from different families to substrate proportion and control released fertilizer
ZHANG Dongbei, WANG Xiuhua, ZHOU Shengcai, WU Xiaolin, CHU Xiuli, ZHOU Zhichun
2019, 36(5): 1044-1050. doi: 10.11833/j.issn.2095-0756.2019.05.026
[Abstract](1759) [HTML] (443) [PDF](20)
To determine the suitable substrate proportion (SP) and control released fertilizer (CRF)loading level for container seedlings from different families. SP and CRF, two key factors for container seedling cultivation, were tested. This research used mass on pine container seedlings from different families as objects. A two factor test for SP and CRF loading and for different levels of each factor was carried out with factorial test. SP was given four levels and CRF was three levels, so there were twelve treatments totally. And each treatment was replicated three times. The effects of SP and CRF loading levels and their interactions on growth, N and P absorption, and seedling use were analyzed with a single factor analysis and a correlation analysis. Then, suitable SP and CRF loadings for quality container seedlings were selected. Results showed no obvious effects from SP on three seedling families; whereas, CRF loading was significant according to the single factor analysis. The interaction of SP and CRF in the two factor analysis of different seedling families varied. Family 32 displayed a noticeable response with the best treatment group being a volume ratio of peat to chaff in the substrate of 5:5 and a CRF loading of 3.5 kg·m-3 with both growth as well as N and P use being better compared to other groups. Neither family 35 or 36 showed significant differences between treatment groups, but both gave an significant response to CRF loading with family 35 having a loading of 2.5 kg·m-3 and family 36 of 3.5 kg·m-3, individually. According to the two factor analysis of family and CRF loading and the correlation analysis between growth and nutrition use indexes, the effect of CRF on seedlings was more obvious than family. Therefore, for quality seedlings, attention should be placed on 1) not only growth traits, but also on ensuring a proper substrate nutrition level for seedling requirements, and 2) different cultivation measures to be used for seedlings of different genetic background because of their different growth traits.