The Comparative Study Of Drought Capacity In Different Plant Community In Typical Steppe

Combine the dynamic changes of plant water potential in persistent drought conditions ,the characteristic of change of soil water potential and the major plant species water potential in different communities before and after irrigation,the main factors which decide plant water potential and soil water potential to comparative study of drought resistance capacity of plants in different Community community in Inner Mongolia typical steppe , this text get the following conclusions:1. With the increase in intensity of drought stress, the plant water potential decreased. Potential minimum on the mean value of the first plant, and its drought resistance capacity of the weakest. In the restoring community plot and the community outside the degenerative plot, the daily average of leaf water potential of the plant outside the Anti-Canopy were higher than the daily average of leaf water potential of the plant where leaking inside of the Anti-Canopy and not inside of the Anti-Canopy. After two months of sustained drought, and there will be some plants survived, indicating that the drought would have an impact on succession, but not enough to form a bare land, succession to start.2. After irrigation in the different communities, the changes of plant water potential are different. In the restoring community plot and the community outside the degenerative plot,the absorption layer of Carex korshinskyi Kom is the most shallow, the absorption layer of Cleistogenes squarrosa (Trin.) Keng and Carex korshinskyi Kom are deeper, Leymus chinensis, Agropyron michnoi Roshev and Stipa grandis P. Smirn are the deepest . The increase of the daily average of leaf water potential of the plant in the restoring community plot apparently higher than the increase of the daily average of leaf water potential of the plant in the community outside the degenerative plot.In the same condition, the restoration of the soil of the restoring community plot is better than the community outside the degenerative plot, soil moisture easily absorbed by plants.Retiring things like rising slower plant water potential is illustrated in the existence of soil compaction layer.3. After irrigation in the different communities, all levels of the changes in soil water potential varies. In the restoring community plot and the community outside the degenerative plot, the water content for 0-10cm,10-20cm are most effected after irrigation, corresponding to 10cm, 20cm soil water potential values had greater influence. Soil water potential fluctuations were irregular, reflecting the different soillayers at different times have different consumption and supply.4. To sum up the above analysis shows that the deep roots of plants, the droughtresistance capacity of the restoring community plot as the same as the drought resistance capacity of the community outside the degenerative plot.However,the plants for the shallow root system, the drought resistance capacity of the restoring community plot are inferior to the drought resistance capacity of the community outside the degenerative plot.5.Under the continuing drought conditions, the rate of decline of soil water content of the community outside the degenerative plot was significantly higher than the rate of decline of soil water content of the restoring community plot. Under the natural state,the soil water content change as the rainfall in the restoring community plot and the community outside the degenerative plot.