The Population Genetic Structure Of Pseudostellaria Heterophylla With Dimorphism Breeding System

As the most basic characteristic parameters of plant populations, breeding system could control the transmission and communication of genes among neighboring generations, thus having a great influence on the genetic structure of the plant population. The genetic structure of populations not only includes the level of genetic variation but also contained the distribution of genetic variation. Pseudostellaria heterophylla, which is a typical Dimorphism Breeding System, was classified into two types:one was CH flower-attracting pollinators, the other was CL flower-focusing on the self-pollination. However, the knowledge of plant populations’genetic structure in the Dimorphism Breeding System was very little for us. This study aimed to probe the relationship between plant populations and Dimorphism Breeding System so as to propose an important mechanism which keeped CH/CL development in the plant populations through taking samples of Pseudostellaria heterophylla for a total of3plant populations which were the different ages (Three Age, Two Age and One Age) at the three areas named Heigou, Laohugou and Jinshan of Dandong City, Liaoning Province and using RAPD Molecular Maker Technology to study the genetic structure and diversity of plant populations. The results of the research were as follows:By using8random primers to amplify Pseudostellaria heterophylla (Three Age, Two Age and One Age),164individuals,3populations in total, the conclusions were drawn from the stripe matrix analyzed by POPGNE32:from the level of species, P values of Pseudostellaria heterophylla (Three Age, Two Age and One Age) were respectively0.3142,0.3731and0.3078; H values of Pseudostellaria heterophylla (Three Age, Two Age and One Age) were0.3142,0.3731and0.3078; I values were0.4587,0.5511and0.4619. Based on the results, it could be seen that the different ages of Pseudostellaria heterophylla showed a very abundant genetic diversity in the level of species. From the level of populations, H values turned out to be0.1218,0.1748and0.1616respectively with the distribution of I values-0.1772,0.2579and0.2362, which manifested that the genetic degree of each age’s Pseudostellaria heterophylla in the level of populations was not rich. From the genetic differentiation, the Gst values of Pseudostellaria heterophylla (Three Age, Two Age and One Age) were0.6137,0.5286and0.5294, implying that the genetic variation of each age’s Pseudostellaria heterophylla mainly appeared in the populations where genetic variation was relatively small and the coefficient of the genetic differentiation, which was far higher than the Gst value (0.216) of the mixed plants, and much closer to the Gst value (0.510) of the self-pollination. Besides, the Nm values of each age’s Pseudostellaria heterophylla (from One Age to Three Age) were respectively0.3147,0.4460and0.4445, which are obviously lower than Nm value (2.99) of the mixed plants but similar to the self-pollination’s (Nm=0.43).The above results both suggested that the breeding system of Dimorphism Pseudostellaria Heterophylla (CH/CL) had a great influence on the genetic structure of populations. Compared with CH flowers, the CL flowers could produce a great amount of seeds, which caused that the breeding way of Pseudostellaria heterophylla was much closer to that of the self-pollination. What’s more, Pseudostellaria heterophylla made use of subterraneous succulent roots to conduct cloned propagation (or called vegetative propagation) to generate a lot of CL and to yield fully grown seeds thus the value of the genetic differentiation of Pseudostellaria heterophylla was greatly similar to the self-pollination. The CL flowers produced so many seeds, which was closely related to the local climate.