Effects Of Soil Relative Water Content On The Growth And Physiology Of Pepper

Taken the pepper cultivar (LongJiaoNO.2)as materials, the pot experiment in the continental arid climate (Liangzhou District, Wuwei City,Gansu Province)studied the effects of different soil relative water content with 80%,60% and 40% and after the soil relative water content with 40% rewatered to 60% on the growth, yield per plant and MDA content, protective enzym activity, osmotic adjustment substance and chlorophyll fluorescence parameters in the leaves of pepper. The experimental results are as follows:1. The soil relative water content with 60% concerning about height and stem diameter of pepper plants, fresh and dry weight of shoots and root shoots, yield per plant were better than 80% and 40% ones. During the whole of period, R/S ratio of the pepper in the treatment with 40% soil relative water content was higher than the other two treatments. The rewater treatment after drought stress has certain effects on compensation. And with the extension of time on rewater treatment, the effects will gradually strengthen.2. In the whole period of soil moisture, the MDA content in pepper leaves was in increased trend and the activities of SOD and POD were increased firstly and then decreased. The MDA content and SOD activity in leaves of the treatment with 40% water holding was higher than the 80% and 60% treatments. Differently, the POD activity in leaves of 40% treatment was higher than the other two groups with 60% and 80% treatments, but decreased in the last period. The content of MDA together with the activities of SOD and POD in pepper leaves were decreased by water renewal treatment. The SOD activity was decreased and the POD activity was increased. The MDA content was decreased significantly after 15d of rewater treatment.3. In the period of soil moisture, the WSS and Pro content of pepper leaves were increased firstly and then decreased, and the WSP contents of all the three treatments were changed from descent to ascent firstly and then decreased. The accumulations of WSS and Pro under the treatment with 40% soil moisture were more than 80% and 60% treatments. The WSS and WSP contents of pepper leaves were decreased during the rewater treatment after drought stress.4. During the period of soil moisture, Fv/Fm, Fv'/Fm',ΦPSⅡand qP in the pepper leaves with the soil relative water content of 80%,60% and 40% were increased firstly and then decreased. The three treatments of 56d reach to peak. Above mentioned parameters in leaves of 80% and 60% treatment was higher than 40% treatments. The trend of NPQ and qP changed relatively. Pepper leaves treated with 60% of the NPQ changes smoothly in the whole period of treatment. After 56d of the treatment, the NPQ in the pepper leaves with 80% and 40% treatments was rised.5. Integrated the effects of soil relative water content on the growth and physiological indexes, the soil relative water content with 60% is more appropriate for pepper.