The Analysis On Forming Reason And Mechanism Of Reaumuria Soongorica Community In Steppe Region

Reaumuria soongorica is a typical desert plants, with the saline soil can be distributed to the grassland. In the process of desert to grassland, R.soongorica from the zonal vegetation gradually transform to semi-hidden and intrazonal vegetation.Due to the variation of ecological and geographic environment, ecological adaptive mechanisms in the steppe region must distinguish to desert region. This paper through investigation and experimental study on the chang of interspecific competition under salt stress and soil salt content and primary community,the vegetation horizontal pattern of different communities,the vertical and horizontal heterogeneity of soil salt distribution,and dynamic observation of R.soongorica salt secretion,determined that:R.soongorica lose the Competitiveness in non-stressing habitat while Obtain enduring ability in extreme environments. R.soongorica depends on its function of salt excretion form saline island to impact surrounding environment.The salt secretion of R.soongorica is more than the leaching amount or is balanced with eluviation, so to make the saline island long-term stably exist.This habitant construction formed the competitive ability of R.soongorica so as to effectively inhibit the growth of herbs in grassland region. This articlereveals the phenomenon and mechanism that R.soongorica carry out interspecific competition by means inorganic salt asallelopathic substance.The results of plantal historical specialization obtained specific adaptability meanwhile lost other adaptability(include competitive ability). Environmental gradient constructed the zonal distribution of vegetation, plants in the tradeoff in the ecological adaptation is the reason why this distribution formed and stabled.