植物生态学报 ›› 2017, Vol. 41 ›› Issue (3): 359-368.doi: 10.17521/cjpe.2015.0257

• 研究论文 • 上一篇    下一篇

不同基因型羊草数量性状的可塑性及遗传分化

杨雪, 申俊芳, 赵念席*(), 高玉葆   

  1. 南开大学生命科学学院, 天津 300071
  • 出版日期:2017-03-10 发布日期:2017-04-12
  • 通讯作者: 赵念席 E-mail:zhaonianxi@nankai.edu.cn
  • 作者简介:

    * 通信作者Author for correspondence (E-mail:sunzhiqiang1956@sina.com)

  • 基金资助:
    国家自然科学基金(31570427)

Phenotypic plasticity and genetic differentiation of quantitative traits in genotypes of Leymus chinensis

Xue YANG, Jun-Fang SHEN, Nian-Xi ZHAO*(), Yu-Bao GAO   

  1. College of Life Sciences, NanKai University, Tianjin 300071, China
  • Online:2017-03-10 Published:2017-04-12
  • Contact: Nian-Xi ZHAO E-mail:zhaonianxi@nankai.edu.cn
  • About author:

    KANG Jing-yao(1991-), E-mail: kangjingyao_nj@163.com

摘要:

为了深入探讨植物对环境变化的适应机制, 该文以内蒙古草原区羊草(Leymus chinensis)不同基因型为对象, 在人工控制条件下, 研究了羊草基因型、刈割、干旱及其交互作用对羊草11个数量性状的影响。结果显示: (1)所观测的11个性状(光系统II光化学效率、最大净光合速率、蒸腾速率、比叶面积、相对生长速率、分蘖增长数、地上及地下生物量、叶总酚浓度、根非结构性碳水化合物总量和根冠比)受环境因素(干旱、刈割或两者交互)影响显著, 表明该物种具有较强的表型可塑性; 且在4种环境条件(对照、刈割、干旱、刈割干旱)下, 不同基因型羊草的反应规范并不一致, 其中, 最大净光合速率、蒸腾速率、比叶面积、相对生长速率、叶总酚浓度和根非结构性碳水化合物总量受环境和基因型交互作用影响显著, 表明这些性状的表型可塑性具有一定的遗传基础。(2)对同一环境条件下, 不同基因型间的性状进行分析显示, 分蘖增长数、地下生物量和根非结构性碳水化合物含量在4种环境条件下均未检测到基因型间的差异; 而其余8个性状在基因型间的差异显著, 表明这些性状的差异具有一定的遗传基础, 其中, 与生长相关的6个性状的遗传力(H2)较高, 均大于0.5, 而叶总酚浓度和根冠比仅在刈割干旱条件下检测出显著差异, H2分别为0.145和0.202。这些实验结果为理解羊草这一重要物种在内蒙古草原区的广泛分布提供了适应机制方面的数据支持, 为合理预测未来气候变化对该物种的影响提供了科学依据, 为合理利用和保护该物种及其生态系统提供了理论依据。

关键词: 羊草, 基因型, 适应, 遗传分化, 表型可塑性, 反应规范

Abstract:
Aims Adaptation mechanisms of plants to environment can be classified as genetic differentiation and phenotypic plasticity (environmental modification). The strategy and mechanism of plant adaptation is a hot topic in the field of evolutionary ecology. Leymus chinensis is one of constructive species in the Nei Mongol grassland. Particularly, Leymus chinensis is a rhizomatous and clonally reproductive grass, a genotype that can play an important role in the community. In this study, we aimed to (1) investigate the phenotypic plasticity of L. chinensis under different conditions, and (2) test the genetic differentiation and reaction norms (the relationship between the environment and the phenotype of an individual or a group of individuals) under four environmental conditions among different genotypes of L. chinensis. Methods Ten genotypes of L. chinensis were randomly selected. Under the control condition, we studied the effects of genotype, defoliation, drought and their interactions on 11 quantitative traits of growth (8 traits including photochemical efficiency of photosystem II, maximum net photosynthetic rate, transpiration rate, specific leaf area, relative growth rate, the number of tillers increased, aboveground and underground biomass growth), defense (total phenol concentration of leaf) and tolerance (non-structural carbohydrate content of root, root/shoot ratio) of L. chinensis. We studied the phenotypic plasticity, genetic differentiation and reaction norms mainly through tested the effect of environment and genotype on these traits. Important findings First, all 11 traits showed obvious phenotypic plasticity (i.e., significant effect of drought, defoliation and their interactions). The expression of 10 genotypes of L. chinensis was divergent under different environmental conditions. Interactions of genotype and environment significantly affected the maximum net photosynthetic rate, transpiration rate, specific leaf area, relative growth rate, total phenolic concentration of leaf, and total non-structural carbohydrate content of root. This indicated that the phenotypic plasticity of these five traits exhibited genetic differentiation. Second, the increase of number of tillers, belowground biomass and non-structural carbohydrate content of root did not show genetic differentiation under the same condition. The other eight traits showed significantly genetic differentiation, and the heritabilities (H2) of six traits related to growth were higher than 0.5. The leaf total phenol concentration and root/shoot ratio showed genetically differentiation only under the drought and defoliation condition, with the heritabilities being 0.145 and 0.201, respectively. These results explained why L. chinensis widely distributed in the Nei Mongol grassland, and provided genetic and environmental basis for related application and species conservation in this grassland ecosystem.

Key words: Leymus chinensis, genotype, adaptation, genetic differentiation, phenotypic plasticity, reaction norm