Detection Of Genetic Diversity And Ecological Differentiation Of Sect. Leiostipa Dum. In Inner Mongolia Steppe

This paper studied the five plants of Sect. Leiostipa Dum.—Stipa grandis P. Smim., Stipa krylovii Roshev., Stipa baicalensis Roshev., Stipa bungeana Trin.和Stipa przewalskyi Roshev., they are perennial grasses with kinships and quite similar morphological characteristics.Distributed in steppe region and desert region in Inner Mongolia, they are edificators of communities.Molecular biological method and physiological method were used to discuss genetic diversity and ecological differentiation of Sect. Leiostipa Dum. though variances of morphological characteristics, physiological characteristics and genetics.The results were as follows:1. Stipa grandis and Stipa krylovii are different in genetic diversity and overgrazing causes genetic variation through RAPD analysis, phylogenetic analysis based on internal transcribed spacer (ITS), morphology and anatomy of flower and water potential.2. High genetic diversity exsists in the populations ofStipa grandis and Stipa krylovii.The percent of polymorphic loci of Stipa grandis is 80.97%, and Stipa krylovii is 80.97%.3. The populations of Stipa grandis exsist different genetic variability during the different restoring succession.The longer the enclosed is,the smaller the genetic distance is.4. The results of gene flow among Stipa grandis populations is that: Nm=1.3149(＞1), Gst=0.3772.But the result of gene flow among Stipa krylovii populations is that: Nm=0.8809(＜1), Gst=0.4138.We can inferred that Stipa grandis and Stipa krylovii are geitonogamy-outcross breeding plant.5. There are more genetic variability and closer relationships among the five kinds of plant of Sect.Leiostipa Dum..And the bands have the high level of polymorphism.The number of special bands is less.6. DNA(RAPD)analysis showed: The relation between genetic distance and geographical distance of Sect.Leiostipa Dum.is that the nearer the geographical distance is, the smaller the genetic distance is.