Population Characteristics And The Genetic Diversity Of Ammopiptanthus Mongolicus In The Desert Of A La Shan

Ammopiptanthus mongolicus is the important constructive species in Alxa desert region, which has important significance to maintain the stability of the ecological system. By natural conditions and human activities, to some extent, the distribution of this species gradually reduced, and is now in severe endangerment. Study on different habitats of Ammopiptanthus mongolicus in Alxa by using technique of RAPD molecular markers and adopting field investigation with analysis of data statistics, in this paper we give the following results:1.The Ammopiptanthus mongolicus which distribute in mountains, fixed sandy land and half -fixed sandy land are in decline stage, the situation is in contrast with the other region, such as alluvial fan. The Habitat in alluvial fan is more suitable for the growth and breeding, so it should be especially protected.2. The spatial pattern of the whole population is contagious distribution in all kinds of Habitat, but it shows a different aggregation degree, in which the biggest aggregation degree is the plant in alluvial fan. Along with the growth of Ammopiptanthus mongolicus, the phenomenon of self-thinning become more and more significant,. On the country, the aggregation degree gradually decreased.3. The genetic distances being 0.3078-0.6870 and the identity being 0.5031-0.7351 among populations. The genetic relationships among Luanjingtan (LJT) and Yabulai (YBL) are relatively close, the genetic relationships among Jiangui (JG) and Helanshan (HLS) are relatively close. The formations of phenotypic characteristics was mainly influenced by the habitat, were no obvious connection with genetic relationships.4.Through cluster analysis on the RAPD bands, The percentage of polymorphic bands (PPB) was 55.36%, the genetic diversity from high to low was found respectively in Helanshan (HLS)>Luanjingtan (LJT)>Jiangui (JG)>Yabulai (YBL)>Jilantai (JLT). Effective number of alleles, Nei’s gene diversity and and Shannon’s information index were 1.6073,0.3468 and 0.5119 at species level. The results indicate that Ammopiptanthus mongolicus in this area has relatively low genetic diversity and most of differentiation is within populations.5. The overall region start with western part of Yinshan Mountain then along Helan Mountains once was continuous distribution, obstructed by the Ulan Bub Sandy Land, Kubuqi Desert, Tungeli desert and Badan Jilin desert, formed Jilantai population.