Knowledge Resource Center for Ecological Environment in Arid Area
| 环境异质性对潜在粮食作物沙米表型变异的影响 | |
| 其他题名 | Phenotypic variation of a potential food crop, Agriophyllum squarrosum, impacted by environmental heterogeneity |
| 尹成亮 | |
| 出版年 | 2016 |
| 学位类型 | 硕士 |
| 导师 | 马小飞 |
| 学位授予单位 | 中国科学院大学 |
| 中文摘要 | 植物的表型变异是遗传变异与环境异质性共同作用的结果，长期适应不同生境造成植物的表型和遗传发生显著分化。为了深入理解沙生植物适应沙漠环境的异质性环境的遗传基础，我们对广布于我国温带沙漠流动沙丘、半流动沙丘或河岸沙地的固沙先锋植物沙米（学名沙蓬，Agriophyllum squarrosum）进行了同质园实验，调查了采集自不同种源的26个沙米群体的表型特征和生殖策略，统计分析了包括植株高度、茎直径、基部分枝长、地上生物量、收获种子重量和种子粒径等重要生态农艺性状的变异模式，利用Canoco软件的RDA分析调查了沙米表型与19个生态气象因子之间的关系，比较其数量性状表型分化、基于ITS序列变异的遗传分化及环境异质性之间的关系，结果发现：1). 沙米表型性状呈现出以纬度变异为主的梯度变异模式。与北部群组相比，南部群组表型性状内部差异大，多样性高；除种子粒径外，其它表型呈现出南部群组大于北部群组。南部群组趋向营养生长，而北部群组更倾向生殖生长。发现北部群组表型与降雨量相关性大，而南部群组表型随温度变化明显，说明不同群组的生长特性与物质分配具有一定的局域适应性和遗传差异。2). 通过QST与FST南北群组间和组内比较发现，南北群组间和南部群组组内的FST值均高于QST值，表明群体处于稳定的一致选择(unifying selection)之中；而北部群组组内QST值均大于FST值，表明存在明显的地方适应性，居群间个体的混合存在远交衰退的风险，因而可以将南部居群移植到北部居群来进行沙米居群的遗传复壮。此外，在南北群组间种子大小和基部枝长的QST值均高于环境异质性分化，说明该表型的本地适应性不能完全被基于温度和降雨量的环境异质性所解释。通过对风力大小与性状的相关性分析发现，冬季最大风速显著影响沙米种子大小，而基部枝长则与7、8月最大风速正相关，说明沙米的表型分化是适应不同风沙环境的结果。这一研究不仅为沙米野生资源对环境和气候变化的适应潜力评估提供新方法，并对其引种驯化提供重要种质资源和突破方向，并为野生资源植物的生态适应性遗传机理研究提供研究范例。 |
| 英文摘要 | Phenotypic variation of plants is the outcome of combined action of genetic variation and environmental heterogeneity. Plants long-term adapt to different habitats significantly cause plant phenotypic and genetic differentiation. Agriophyllum squarrosum, also called “sand rice”, is a pioneer annual plant endemic to the mobile and semi-fixed sand dunes across the temperate deserts of China, which has important values for eco-agriculture and is an ideal material for the adaptive evolution studies. In order to understand the ecological genetic basis of how psammophyte adapt to the heterogeneous environment of deserts, in this paper, based on a common garden experiment from 26 populations of A. squarrosum, we investigated the relationship between the bio-climatic factors of original habitat and a couple of important agronomic traits, including Plant height (PH), Seed weight (SW), Stem diameter (STD), Basal branch length (BBL), Above-ground biomass (AGB) and Seed diameter( SED). Based on 19 bio-climatic factors from DIVA-GIS, redundancy analysis with Cannoc software. We also analyzed the relationships between/among the quantitative traits, the genetic differentiation based on the variety of nrITS and the heterogeneity of environment. Results showed:1). In general, all the phenotypic traits were significantly related to the latitudinal gradient. Except SED, all the traits were higher in the South group than the North group. Our results suggested that all the phenotypic traits were differentiated among the two groups, especially within the populations among the southern group. Meanwhile, the South group tends to the vegetative growth, while the North group tends to reproduction growth. What’s more, the North group was more affected by precipitation, whereas the south group was more affected by temperature. This phenomenon indicated that the natural variations on growth characteristics and energy distribution among the populations of A. squarrosum had been largely impacted by local adaptation and genetic differentation. 2).Comparison between the inter- and intra-groups showed that the values of FST were much higher than that of QST within the south group and among all populations, suggesting an unifying selection were acting in these populations. However, QST was found to be higher than FST in the north group, supported the local adaptation of the northern populations. This result indicated that these populations will be under a potential risk of outbreeding depression. Therefore, translocation of the southern genotypes into the north habitat will contribute to the genetic reinforcement of the northern populations. Furthermore, the values of QST on the traits of seed diameter (SED) and basal branch length (BBL) were higher than that of environmental heterogeneity (Est) between the two groups, suggested that the climatic differentiation on the temperature and precipitation can not fully explain the phenotypic variation. Thus, we analyzed the relationships between wind speed and the phenotypic traits. Our data showed that the maximum wind speed in winter was strongly correlated with SED, while BBL was more affected by the maximum wind speed in July and August, which suggested that the blown sand environment plays an important role in shaping the adaptive phenotypic differentiation between groups in the desert plant species. In summary, this study not only provided a new evaluation method for adaptive potential in wild resources mitigating climate change, but also shed light on better understanding of the ecological genetic basis for how A. squarrosum adapted to the heterogeneous desert environment, which will further provide both the experienced data and theoretical basis for domestication of valuable desert plants. |
| 中文关键词 | 沙米 ; 同质园实验 ; 环境异质性 ; 物种驯化 |
| 英文关键词 | Agriophyllum squarrosum common garden experiment environmental heterogeneity plant domestication |
| 语种 | 中文 |
| 国家 | 中国 |
| 来源学科分类 | 生物工程 |
| 来源机构 | 中国科学院西北生态环境资源研究院 |
| 资源类型 | 学位论文 |
| 条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/287708 |
| 推荐引用方式 GB/T 7714 | 尹成亮. 环境异质性对潜在粮食作物沙米表型变异的影响[D]. 中国科学院大学,2016. |
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