Study On The Ecophysiology Of Sabina Vulgaris Community At The Different Successional Stages In Mu Us Sandland

Sabina vulgaris plays an important role on preventing desertification. This dissertation discussed ecophysiology of S. vulgaris community through plant community, population, soil, physiological characters and genetic diversity as well at the different successional stages. The results are summarized as follow:The autogenic succession process of vegetation in Mu Us Sandland is from Psammochlou uillosa+Agriophyllum arenarium (Artemisia sphaerocephala) on semi-drift-sand dunes to Artemisia ordosica + S. vulgaris on semi-fixed-sand dunes, then through S. vulgaris+ Poa sphondylodes on fixed-sand dunes, and S. vulgaris on fixed dunes of subclimax stage, to S. vulgaris+moss community on old-fixed-sand dunes which maybe pass to a Stipa bungeana steppe. The S. vulgaris community succession contains progressive and regressive succession. Species diversity increased with the development of the progressive succession, and the ecological environment began getting wet.With the progressive succession, the gravel contents and C/N decrease, silt and clay contents increase, whereas with the regressive succession, things become to opposite. Richness and coverage of species show positive correlation with most index of the soil but negative correlation with C/N. The vegetation succession has effect on accumulation of the organic substances, the relation between number of species, coverage, clays and C/N is close.With the process of the succession, contents of leaf water decrease. Contents of CHLa,CHLb and CHLa+b increase first and then decrease, but the change of contents of CHLa/b is not significant. PRO and MDA contents increase first, and then decrease during the process of the succession. The variance analysis showed that the difference of the PRO contents among stages is more significant.The difference of the SOD and POD activity is more significant among stages, but the CAT activity has no significant change. In the fourth successional stage, the contents of leaf water and chlorophyll decrease, the MDA contents and PRO increase, the activity of SOD and POD increase. All of them show the physiological characters of damaged plant under the environment hardness. It is showed that the decrease of the soil index makes the contents of PRO and MDA accumulated and the protective enzymes activity increased. The responsion of the physiological index to the environment hardness in different successive stage is not similar. First, some damaged characters appeared in the forth stage;...