高山嵩草种群在放牧干扰下遗传多样性的变化

doi:10.3773/j.issn.1005-264x.2009.05.016

摘要/Abstract

摘要：

利用SRAP (Sequence-related amplified polymorphism)分子标记, 对放牧干扰下的高山嵩草(Kobresia pygmaea)种群进行了遗传多样性研究, 获得了下述结果: 1) 20对SRAP引物组合共检测出448条清晰条带, 其中376条条带具有多态性, 多态位点百分率为83.93%, 随着放牧强度的增加, 高山嵩草种群多态位点百分数、Nei’s遗传多样性指数、Shannon信息指数均下降。2)高山嵩草种群具有较高的遗传多样性和较低的遗传分化(总的遗传多样性H_t为0.276 6, 种群内遗传多样性H_s为0.243 6, 遗传分化系数G_st为0.119 4, 基于G_st估计的基因流N_m^*为1.843 4), 但随着放牧强度的增加, G_st增加, N_m^*降低, 说明放牧限制了种群间的基因交流, 使种群发生遗传分化。3)不同放牧梯度的高山嵩草种群间的遗传距离很小, 但是随着放牧强度的增加, 种群间的遗传距离逐渐增加, 遗传一致度降低。根据遗传距离所构建的UPGMA聚类图中高山嵩草4个种群随着牧压的增加, 逐级聚在一起。

关键词: 高山嵩草种群, 遗传多样性, 相关序列扩增多态性(SRAP)

Abstract:

Aims Our objective was to explore differences in genetic diversity of Kobresia pygmaea populations related to grazing intensity to help prevent grassland degradation and contribute to ecology, genetics and evolutionary ecology.
Methods We randomly selected tender leaves from 25 K. pygmaea individuals from four populations along a gradient of grazing intensity, used SRAP (Sequence-related amplified polymorphism) molecular markers, and examined the genetic diversity of the populations to determine the effect of grazing disturbance.
Important findings We used 20 primers and produced 448 clear bands, 376 (83.93%) of which were polymorphic. With increased grazing intensity, the percentage of polymorphic loci, Nei’s genetic diversity index and Shannon information index of the K. pygmaea populations decreased. Total genetic diversity (H_t) of the four populations under different grazing intensities was 0.276 6, genetic diversity within the four populations (H_s) was 0.243 6, genetic differentiation coefficient among populations (G_st) was 0.119 4 and gene flow (N_m^*) was 1.843 4. With increased grazing intensity, G_st increased and gene flow decreased. Therefore, grazing increased genetic the differentiation coefficient among populations, restrained gene transfer among populations and promoted population gene differentiation. The genetic distance of the four populations with different grazing intensities was small; however, with increased grazing intensity, genetic distance slowly increased and genetic consistency among populations decreased. The UPGMA dendrogram constructed by genetic distance arrayed the four populations in order of increasing grazing pressure.

Key words: Kobresia pygmaea population, genetic diversity, Sequence-related amplified polymorphism (SRAP)

刘伟, 王曦, 干友民, 黄林凯, 谢文刚, 苗佳敏. 高山嵩草种群在放牧干扰下遗传多样性的变化. 植物生态学报, 2009, 33(5): 966-973. DOI: 10.3773/j.issn.1005-264x.2009.05.016

LIU Wei, WANG Xi, GAN You-Min, HUANG Lin-Kai, XIE Wen-Gang, MIAO Jia-Min. GENETIC DIVERSITY OF KOBRESIA PYGMAEA POPULATIONS ALONG A GRAZING GRADIENT. Chinese Journal of Plant Ecology, 2009, 33(5): 966-973. DOI: 10.3773/j.issn.1005-264x.2009.05.016

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https://www.plant-ecology.com/CN/Y2009/V33/I5/966

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参考文献 22

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项目 Item	放牧压力 Grazing pressure
项目 Item	对照 CK	轻度放牧 LG	中度放牧 MG	重度放牧 HG
群落优势种与主要伴生种 Community dominant species and main companion species	1、2、3、4	1、2、4、5	4、1、3、6	5、6、1、4
多年生牧草种数 No. of perennial species	15	12	8	5
一、二年生植物种数 No. of annual species	7	11	13	15
植被盖度 Vegetation cover (%)	96	83	65	51
植被高度 Vegetation height (cm)	28	18	13	6
7月干草产量 Dry weight of plant community in July (g·m^-2)	368.3	213.8	135.7	64.9

项目 Item	放牧压力 Grazing pressure
项目 Item	对照 CK	轻度放牧 LG	中度放牧 MG	重度放牧 HG
群落优势种与主要伴生种 Community dominant species and main companion species	1、2、3、4	1、2、4、5	4、1、3、6	5、6、1、4
多年生牧草种数 No. of perennial species	15	12	8	5
一、二年生植物种数 No. of annual species	7	11	13	15
植被盖度 Vegetation cover (%)	96	83	65	51
植被高度 Vegetation height (cm)	28	18	13	6
7月干草产量 Dry weight of plant community in July (g·m^-2)	368.3	213.8	135.7	64.9

引物对 Primer pairs bands	扩增总条带数 Total No. of polymorphic	多态性条带数 No. of polymorphic bands	多态性比率 Percentage of polymorphic bands (%)
me1-em1 me1-em2 me1-em3 me1-em8 me1-em12 me1-em16 me2-em4 me2-em5 me2-em7 me2-em13 me2-em16 me5-em1 me5-em2 me5-em3 me5-em4 me5-em5 me5-em7 me6-em11 me11-em5 me11-em7	34 18 24 17 17 25 19 19 17 19 30 25 23 21 26 21 20 27 22 24	27 16 22 13 16 23 12 15 15 17 24 24 19 19 21 18 17 24 19 21	79.41 88.89 79.16 76.47 94.12 80.00 63.16 78.95 88.24 89.47 80.00 96.00 82.61 90.48 80.77 85.71 85.00 88.89 86.36 87.50
总计 Total	448	376
平均值 Average	22.4	18.8	83.93

引物对 Primer pairs bands	扩增总条带数 Total No. of polymorphic	多态性条带数 No. of polymorphic bands	多态性比率 Percentage of polymorphic bands (%)
me1-em1 me1-em2 me1-em3 me1-em8 me1-em12 me1-em16 me2-em4 me2-em5 me2-em7 me2-em13 me2-em16 me5-em1 me5-em2 me5-em3 me5-em4 me5-em5 me5-em7 me6-em11 me11-em5 me11-em7	34 18 24 17 17 25 19 19 17 19 30 25 23 21 26 21 20 27 22 24	27 16 22 13 16 23 12 15 15 17 24 24 19 19 21 18 17 24 19 21	79.41 88.89 79.16 76.47 94.12 80.00 63.16 78.95 88.24 89.47 80.00 96.00 82.61 90.48 80.77 85.71 85.00 88.89 86.36 87.50
总计 Total	448	376
平均值 Average	22.4	18.8	83.93

项目 Item		样本数 Sample size	多态位点 Polymorphic loci	多态位点百分比 Percentage of polymorphic loci	Nei’s遗传多样性指数H*	Shannon信息指数I*
对照 CK	平均值 Mean	25	358	79.91%	0.266 9^a	0.405 2^a
	标准误差 SD				0.178 5	0.244 8
轻度放牧 LG	平均值 Mean	25	340	75.89%	0.246 7^ab	0.372 3^ab
	标准误差 SD				0.190 7	0.265 9
中度放牧 MG	平均值 Mean	25	334	74.55%	0.242 4^ab	0.367 0^ab
	标准误差 SD				0.188 6	0.264 1
重度放牧 HG	平均值 Mean	25	324	72.32%	0.218 5^b	0.334 7^b
	标准误差 SD				0.187 1	0.263 3
物种水平					0.276 6	0.539 0
Species level					0.141 4	0.177 6