• 研究论文 •

### 不同基因型羊草数量性状的可塑性及遗传分化

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

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.