Study On Phenotypic Plasiticity And Its Intergenerational Transmission In Arabidopsis Thaliana

Pot experiments with some genotypes of Arabidopsis thaliana(N1266,N1092,col-0 and ws-0) as planting material were conducted, through which phenotypic plasiticity of higher plant as well as its intergernerational transmission was examined.Both genotypes of N1266 and N1092 showed a significant plasticity response to soilwater. However, the.plasticity of phnology traits of the two genotypes appeared different characteristics:as the soilwater condition was improved, for the humid-ecotype N1266 phonological phase was postponed, and the growing period is prolonged; but for the arid-ecotype N1092, phenology phases were shortend first and then prolonged. This result demonstrated that phenotypic plasticity is an important part of ecology strategy of different species.In addition, the average values of all of leaf morphological traits in N1266 were larger than that of N1092, which proves clearly again that the leaf surface area shrinking is a kind of adaptation to the water shortage in the arid environment. Along the soilwater gradient, the change in leaf morphological index of both N1266 and N1092 is beneficial to increase the leaf area of plants.However, for N1266 as the soil water reached to 40% of the field moisture capacity and 40% of it for N1092, the mentioned tendency changed reversely, inflexion pointappeared in the the reaction norm curves, implying that a best balance between leaf surface and soil water supply is reached. The inflexion point is a threshold of the response of leaf morphological phenotype to moisture, which can be used for specific species as a reference index of the water management in the filed.For the two wild genotypes of Arabidopsis thaliana col-o and ws-O,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 soilwater 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 significan t interactions on specific traits may display non-significant effects individually. In responses to the interactive effects of the studied ecological factors, nine phenotypic traits exhibitedplasticity 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 afected by any of the ecological factors nor their interactiuonsThree successive generation of certain genotyps of Arabidopsis thaliana were implemented contionuously under certain cultivate condition. We found that the generation number affect the phnotypic traits of plant extensively, moreover, most response of pheno-trais to the generation number are plastic. For the three successive generation, the reaction norm cuves of a certain pheno-trait response to a certain ecological factor have consistent direction and slope, providing an evidence to the intergenerational transmission of phenotypic plasticity directly.