生态因子及其交互作用对拟南芥(Arabidopsis thaliana)表型可塑性的影响

以拟南芥(Arabidopsis thaliana)两种基因型(ws-0和col-0)材料,采用复因子混合水平正交试验设计开展盆栽实验,研究了土壤盐分、土壤水分、光照强度、去叶处理等生态因子及其交互作用对受试植株18个表型特征的影响.结果表明生态因子对植物表型可塑性的影响是有针对性的:土壤水分主要影响植物体构件数目;土壤盐分主要影响生物量、角果数及种籽总数等直接反映植株适合度的表型特征;光照条件则主要影响植物的物候表型特征.植物体表型可塑性的方向随水分梯度的变化而发生改变.生态因子交互作用对植物表型可塑性的影响效果不是各因子独立作用的简单加和:对某个表型特征都有显著影响的两个生态因子其交互作用对该特征可能没有影响;反之,受两个生态因子交互作用影响显著的表型特征也可能不受它们的独立影响.在对生态因子交互作用作出响应时,col-0的9个特征表现出可塑性,而ws-0仅有4个表型是可塑的;同一基因型内彼此相关的表型特征在可塑性上也具一致性.抽苔时莲座叶数与角果平均籽粒数不受任何生态因子及其交互作用的影响,这两个表型作为数量特征而未表现出可塑性.

Effects of the ecological factors and their interactions on the phenotypic plasticity of Arabidopsis thaliana

A pot experiment of orthogonal design was conducted to study the effects of four ecological factors, including salt, water, light, and defoliation, and their interactions on 18 phenotypic traits in two genotypes of Arabidopsis thaliana (i.e. genotypes col-0 and ws-0). Results showed that different ecological factors affected the different types of the phenotypic traits: soil water affected mainly the traits relating to modular number; salt affected such traits as biomass, number of siliques, and total number of maturing seeds that directly reflect the plant fitness; and light affected the traits relating to phenology, thus the development of individuals. The directions of phenotypic plasticity of A. thaliana to soil water were variable along the water gradient without an apparent trend. The collective effects of all the factors on phenotypic plasticity were not simply the additive effects of single factors: any two factors could show significant effects on specific traits in the absence of interactions, or any two factors with significant interactions on specific traits may display non-significant effects individually. In responses to the interactive effects of the studied ecological factors, nine phenotypic traits exhibited plasticity in the col-0 genotype, and only four in the ws-0. The inter-related phenotypic traits within the same genotypes displayed the similar patterns of plasticity. The number of rosette leaves at bolting (LN) and the average number of maturing seeds per silique (ANMS) were not affected by any of the ecological factors nor their interactiuons. The reason for lack of plasticity in those two quantitative phenotypic traits requires further investigation.