Effects On Water Physiology Characteristics Of Leaf And Root Of Pugionium Seedlings Under Drought Stress

Pugionium is a cruciferous vegetable, the biennial herbaceous plants, mainly distributed in the Mongolian plateau, the genus is endemic of Mongolian plateau sand in central Asia, and Pugionium is special of China. Pugionium is multifunction sand vegetables such as medical aspect, health care, feeding and sand-fixation.In this experiment annual Pugionium seedlings was used as experimental material, the method of artificial simulation of drought was used, water metabolism index of Pugionium seedlings leaves, photosynthe ic parameters, chlorophyll fluorescence parameters were determinated, and physiological indexes of Pugionium seedlings root were also measured. Main results were as follows(1) The relative water content of leaf decreased compared to the control treatment as stress time extension. The natural saturation deficit of Pugionium seedlings leaves increased compared to the control treatment. The natural saturation deficits increased respectively between MD and VD.The content of free water of Pugionium seedlings leaves decreased gradually. Under LD and VD, The content of bound water of Pugionium seedlings leaves increased during the drought period. The antioxidase of Pugionium seedlings leaves showed an increased trend firstly and then decreased as the drought condition became serious.MDA and PMP of Pugionium seedlings leaves increased as the drought stress extension.(2) The content of chla of Pugionium seedlings leaves showed an increased trend and then decreased. Chlb, chla/b, and car all decreased.The photosynthetic rate and transpiration rate both decreased as the drought stress extension.Intercellular CO2 of Pugionium seedlings leaves showed a decreased trend firstly and then increased. Under drought stress, the parameter Fv/Fm decreased.PS â…¡ decreased slowly and qP decreased as well.The parameter qN increased as drought stress became serious. And ETR decreased as well.(3) Under LD drought stress, the root cap ratio of Pugionium seedlings increased in severe stress.Compared with controls,soluble proteins, proline and soluble sugar of osmotic regulation substances in root showed an increasing trend under drought Stress Under severe stress.Seedling root vigor decreased as the drought stress extension.Compared with the control, malondialdehyde (MDA) content of Pugionium seedlings roots showed significant increasing trend. Superoxide dismutase (SOD) and ascorbic acid content of Pugionium root system increased under LD and MD, and began to decline under VD. Pugionium seedlings root plasma membrane permeability increased as the drought stress extension.