The Study Of Population Adaption Of Arabidopsis Thaliana In The North Of The Tian Shan Mountains

The population is a collection of individuals atthe same time distributed in the same area with heterogeneity, which is the external performance of species. In the changing environment not only individual phenotypic characteristics intercoordination can show individual adaptability,due to the interaction among heterogeneity individuals in populations also showed different changes in the number,maintenance growth model which is comprehensive embodiment of populations to adapt to environmental.As a result of such a research of population adaptation is the based to comprehensive understanding the population evolutionary adaptation.This study first take the natural Arabidopsis thaliana population in Tianshan Mountains and Altai Mountains as the research object, observed population demographic changes for three consecutive years.Comparative analysis the variation of phenotypic characteristics and population variability of plant that germinate in different period, combined with the maternal effect of different germination period of A.thaliana seeds in different temperature, the compensation of survival rate and reproductive rate of plant that germinate in different period,discusses the adaptation mechanism in the north of the Tianshan Mountains,obtain the following conclusions:First, through the observation of population demographic characteristics for A.thaliana in Tianshan and Altai mountains found: 1) A.thaliana populations showed a patchy distribution,the same A.thaliana populations can continued to germinate, early, mid plants accounted for total germination ratio of main part, germination number of late plant accounted for less proportion. 2) The population size of Arabidopsis is always in the dynamic fluctuations in the two regions and population size increased firstly and then decreased. 3) mortality in different periods of germination of plants showing early>middle>late germination of plant number. At the same time, different areas of individual fitness showed a consistent pattern: early>middle> late germination of plant numbers.Second, compared nine plant phenotypic characteristics of the plant that germinate in different period in two different regions found that: 1) The plant that germinate in different period in the same population, except based branches and stem branches the remaining seven phenotypic characteristics have significant differences. 2) In these two regions,late germinated plant had significant differences in reproductive traits(plant pod number, single pod seed number, mean seed number per plant, total number and total weight of fruit) with other period plant. In addition, early and middle plant had significant difference in vegetative growth characteristics(plant height, underground biomass amount and total plant biomass)in Altai mountains.3) The number of basal branches and stembranches had higherdispersion degree which means the variation was larger in the plant, and the variation of the nutrientgrowth traits was larger in the Altai region. 4) In the same region, the number of based branches and stems branches has a higher average coefficient of variation, while the number of single pod seeds of coefficient of variation is low. The average variation coefficient of phenotypic characteristics was not significantly different between the two regions during the same period. 5) The phenotype traits of plant that germinate in different period different germination period showing an overall significant positive correlation, the plant pods number,fruit weight, total plant biomass and plant height of different germination period has extremely significant positive correlation with individual fitnessin two regionsThree, through the study of the maternal effect on the seed from plants germination at different period under different temperatures found: 1) In the same grown season, we find seeds from mothers which germinate in different time can response to the temperature through germination which influenced by maternal effect. The low temperature during early plant seeds matured lead to a higher germination of seeds in high temperature.2) Early and late germination of plants has different survival strategies, early germination of plant tend toexpandthe range of seed germination temperature to promote population growth, later germinating plants tend to make the offspring germinate in the most suitable temperature to keep the population continuing. 4) The optimum seed germination temperature affected the germination time, duration time of germination and half time required to germinate.Four, there is compensation effect of population maintenance between individuals and plants that geminate in different periods. In the final effective population, the number of survival in the late period was higher than that in the middle and early period, while the individual fitness of the early plants was higher than in the middle and late period. Early germination of plants has low survival rate and high fecundity, later germinating plant has the characteristics of high survival rate, low fecundity, the plants germinated between early germination and late germination have both characteristics to maximize the population fitness.In summary, this research first discovered that phenotype traits and germination timeof A.thaliana population are heterogeneity in the Northern Tianshan Mountains, this heterogeneity can largely develop the adaptation strategy of A.thaliana at the population level,which is the important reason for this species distributed in the arid(Altai mountains) and humid environment(TianShan) in Xinjiang.