| The Delphinium grandiflorum is paid more and more attention because of its broad distribution and unique color and pattern. The application of it has broadened in the gardening. This thesis studies on the positive response of the characteristics of seed germination, the changes of morphological appearance, physiological and biochemical characteristics and antioxidant isoenzyme of the Delphinium grandiflorum under water stress conditions. The purpose of the thesis is to study water stress mechanisms of physiological and biochemical adaptation of Delphinium grandiflorum. The study can provide guidance to water-saving irrigation and drought resistance for the growth of Delphinium grandiflorum seedlings. The research has practical significance.l.The experiment measures that the optimum seed germination conditions is 15℃, light/ darkness is 16h/8h, that is low temperature germination of seeds.2.Under the condition of Osmotic stress, along with the increase of PEG concentration and stress time, in addition to the condition of 5% PEG concentrations (the highest germination rate), seed germination of Delphinium grandiflorum is inhibited to different degrees. Under the condition of 25% PEG concentration, plants can't germinate any longer.3. With the prolongation of stress time and the increase of the PEG concentration in the first 8d, Plants seedlings have some damages to some extent and the damage is gradually deepened. With the stress of 25% PEG concentration of seedlings in the first 6d, seedlings have been in severe drought damage.4. Compared with the control, membrane permeability, MDA content, free proline of seedlings' leaves increase to some extent. Soluble protein content decrease first and then increase. And superoxide dismutase, peroxidase activity first increase and then decrease, it is lower than the control. seedlings of Delphinium grandiflorum in the early and mid stage of osmotic stress regulate substances in the body and protective enzyme activities to reduce cell membrane permeability and MDA content, until protection activity of the plant reduce in the latter part which leads to decline of scavenging reactive oxygen and the ability of free radicals.meanwhile lipid peroxidation becomes serious.5. In the process of natural soil drought stress and rehydration, after 20d of watering the seedlings, the plants grow well and the height of plants increase significantly. In the early drought stress, little effect is on the plant morphology. While in the latter part, bottom leaves of plants wilt serious. In the end, the plants wilt serious. After the continuing drought in the 9d, with the beginning of rehydration, through the visual observation, plants' morphology has some recovery, but there is still some differences compared with the control levels. With the condition of drought, the relative membrane permeability, MDA content of the leaves tend to increase and decrease after rehydration. proline content increases first and then decreases and the value decreased rapidly after rehydration, but significantly higher than the control; soluble protein content shows a declining trend, but the value increases after rehydration which is lower than the control. in the process of drought stress, the POD content of plants first increases and then shows a downward trend. POD is slightly lower than the drought after rehydration. But in the latter part the values of POD are higher than the control and the values of SOD show a downward trend. After rehydration plants have slow increase and then decrease, lower than the control.6. In the process of water stress, SOD, POD, CAT isozymes zymogram of leaves make a change. To the isozymes of same parts, some become apparent and their activity becomes stronger. But some the activity reduce or disappear.
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