[Influence of shading during the processes of drought stress and re-watering on the physiological and biochemical characteristics of Haplocladium microphyllum].

An artificial water control experiment was conducted to study the influence of shading on the membrane permeability, osmoregulation capability, and protective enzyme activities of Haplocladium microphyllum during the processes of drought stress and re-watering. Four treatments of shading were installed, i. e., full daylight and 30%, 50% and 70% of shading. During drought stress, the relative water content of H. microphyllum presented a decreasing trend, while the relative conductivity reached the maximum when the drought stress lasted for 21 days, and the conductivity was high up to 58.0% under full daylight. The soluble sugar and free proline contents and the SOD and POD activities of the plant under drought stress were decreased after a sustained increase. During re-watering, the relative water content of H. microphyllum showed an increasing trend, the relative conductivity, soluble sugar and free proline contents, and SOD and POD activities had a slight increase first and decreased gradually then, but the SOD and POD still kept high activities. After re-watering, most of the test indices recovered to the levels before the drought stress. It was suggested that H. microphyllum had the typical characteristics of resurrection plants, possessing a strong capability against drought during the variation of soil moisture content.