The Tibetan antelope （Pantholops hodgsonii）, indigenous to China, became an endangered species because of considerable reduction both in number and distribution during the 20th century. Presently, it is listed as an...
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The Tibetan antelope （Pantholops hodgsonii）, indigenous to China, became an endangered species because of considerable reduction both in number and distribution during the 20th century. Presently, it is listed as an Appendix Ⅰ species by CITES and as Category I by the Key Protected Wildlife List of China. Understanding the genetic diversity and population structure of the Tibetan antelope is significant for the development of effective conservation plans that will ensure the recovery and future persistence of this species. Twenty-five microsatellites were selected to obtain loci with sufficient levels of polymorphism that can provide information for the analysis of population structure. Among the 25 loci that were examined, nine of them showed high levels of genetic diversity. The nine variable loci （MCM38, MNS64, IOBT395, MCMAL TGLA68, BM1329, BMSI341, BM3501, and MB066） were used to examine the genetic diversity of the Tibetan antelope （n = 75） in Hoh Xil National Nature Reserve（HXNNR）, Qinghai, China. The results obtained by estimating the number of population suggested that all the 75 Tibetan antelope samples were from the same population. The mean number of alleles per locus was 9.4 ± 0.5300 （range, 7-12） and the mean effective number of alleles was 6.519± 0.5271 （range, 4.676-9.169）. The observed mean and expected heterozygosity were 0.844 ± 0.0133 （range, 0.791-0.897） and 0.838 ± 0.0132 （range, 0.786-0.891）, respectively. Mean Polymorphism Information Content （PIC） was 0.818 ± 0.0158 （range, 0.753-0.881）. The value of Fixation index （Fis） ranged from -0.269 to -0.097 with the mean of -0.163 ± 0.0197. Mean Shannon＇s information index was 1.990 ± 0.0719 among nine loci （range, 1.660-2.315）. These results provide baseline data for the evaluation of the level of genetic variation in Tibetan antelope, which will be important for the development of conservation strategies in future.
采用温室盆栽实验研究堆肥污泥对两个杨树品种[凌丰三号(Populus×euramaricanacl.‘Lingfeng 3’)和欧美杨108号(Populus×euramericana‘Guariento’)]幼苗叶片的超氧化物歧化酶(SOD)活性、过氧化氢酶(CAT)活性、过氧化物酶(POD)活性、脯氨酸(Pro)及丙二醛(MDA)含量在不同生长季(污泥施用后的4周、9周、16周和21周)动态变化的影响,分别设置低量污泥(15 t hm-2,LS)、中量污泥(30 t hm-2,MS)、高量污泥(60 t hm-2,HS)和对照(不施污泥,CK)4个处理。结果表明:施用堆肥污泥对2个杨树品种幼苗叶片的SOD、POD及CAT活性的影响在不同生长季均为显著,其中POD活性普遍有所降低,SOD活性基本呈现降低趋势,而CAT活性则因不同品种、污泥用量和生长季而异。施用堆肥污泥对两个品种叶片Pro含量的影响除了污泥施用前期(4周后)外,其他生长季均为显著。污泥对2个品种叶片的膜质过氧化的影响在不同生长季有所差异,在4周和21周后的影响均显著,而在9周和16周后的影响均不显著,并且在污泥施用前、中期(即4周和16周后),叶片的MDA含量基本呈现增加趋势,而在21周后MDA含量则普遍有所降低。由此说明,杨树幼苗对污泥施用有一个适应过程,但因品种和污泥用量而异。
【目的】构建赤松赤枯病病基指数(Disease based index,DBI)评价体系,定量评价与林分因子共同作用后,立地因子对赤松纯林中赤枯病发生程度的作用等级。【方法】在林龄相对一致(34±2)年的赤松纯林生态系统中设立临时样地,筛选影响...
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【目的】构建赤松赤枯病病基指数(Disease based index,DBI)评价体系,定量评价与林分因子共同作用后,立地因子对赤松纯林中赤枯病发生程度的作用等级。【方法】在林龄相对一致(34±2)年的赤松纯林生态系统中设立临时样地,筛选影响赤松赤枯病发生的关键林分因子,建立关键林分因子与赤枯病病情指数的函数关系,选取最优模型作为主曲线;将主曲线等比值拉伸得赤枯病病基指数曲线群,其自下而上依次表示不同的病基指数,即立地对赤枯病发生程度的作用等级。【结果】1)基于森林病害发生的基本原理,提出病基指数的概念。2)确定赤松赤枯病病基指数的定量方法,它包含样地的设立、病情指数的调查、林分因子的调查、关键林分因子的筛选、基准点的确定、备选主曲线模型的建立、主曲线模型的确定和评价、主曲线的绘制及曲线群的建立共9个步骤。3)逐步回归分析表明,林分密度是影响赤松赤枯病发生的关键林分因子,依据所提定量方法建立主曲线方程:Q=65.61/(1+e-0.0015 x+2.32),决定系数R2=0.5198,说明拟合方程较可靠,用该模型预估赤松赤枯病的病情指数时,平均预估误差是5.35%。4)将赤枯病病基指数主曲线等比值拉伸得曲线群,即建立定量评价体系。体系中的5条曲线自下而上分别表示为:Ⅰ为极轻病害发生,Ⅱ为轻度病害发生,Ⅲ为中度病害发生,Ⅳ为重度病害发生,Ⅴ为特重度病害发生。【结论】赤松赤枯病病基指数主曲线模型和曲线群图可以定量评价赤松林的立地因子对赤枯病的潜在发生程度的作用等级,可为赤松纯林合理、有效的管理提供理论基础,将成为森林有害生物生态控制方法的重要组成部分。
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