Study On Physiological Response Of Wild Jujube (Zizyphus Jujube Mill Var. Spinosa (Bunge) Hu Ex H.F. Chou) To Soil Water Stress And Tea Processing Technology Of Wild Jujube Leaves

Wild jujube (Zizyphus jujube Mill var. Spinosa (Bunge) Hu ex H. F. Chou), Rhammaceae from Ziziphus, is native to China. Widely distributed in China, it is a good shrub for soil and water conservation commonly found in the Loess hilly regions. Wild jujube is also known as a good fruit tree and medicinal resources. Wild jujube is mainly distributed in arid and semiarid regions, therefore, its yield and quality are significantly influenced by drought condition. The response of water consumption characteristics, secondary metabolism, growth, photosynthesis and osmotic adjustment in wild jujube to different soil water conditions, and the tea processing technology of wild jujube were investigated in this paper. The irrigation and drainage system of wild jujube cultivate was set up in the study. The paper aimed to discuss the drought adaptability of medicinal plant wild jujube, analyze its changing characteristics of constituents and physiology, and provide useful information in exploitation and utilization of wild jujube resources. The main conclusions are as follows.One-year-old wild jujube seedlings, from Yan’an Changtai Pharmaceutical Co. Ltd, were chosen as pot experiment materials. The water consumption characteristics, the secondary metabolism, growth, photosynthesis and physiological changes under three different soil water conditions were analyzed. Results showed that the highest water consumption of wild jujube occurred mostly from the end of July to the middle of August. The abnormal increase of the night water consumption in September was related to leaves senescence and old leaves falling. The irrigation and drainage system of wild jujube cultivate was set up in the study. By analyzing the secondary metabolites of leaves and roots, it was found that the leaf total phenols and nuciferine contents of wild jujube increased significantly under drought stress, but total flavonoids, rutin, jujuboside A and jujuboside B content of wild jujube leaves did not show significant increases. Compared with well-watered condition, the alkaloids content in wild jujube leaves under moderate drought stress decreased significantly, but increased significantly under serious drought stress. There were no significant changes in total flavonoids, total phenols, nuciferine, alkaloids and jujuboside B content of wild jujube root. It was obvious only after middle July that growth of wild jujube was restricted by drought stress. The plant height of wild jujube did not change obviously with the degree of drought stresses. The root elongation decreased obviously under serious drought stress, but it was not true under moderate drought stress. The total water content, underground water content, leaf water content and new root water content of wild jujube under different soil water content showed control> moderate drought stress> serious drought stress. The influence of drought stress on water content in different parts of wild jujube was expressed as:new root>old root> leaves> stem.The influence of drought stress on photosynthesis rate of wild jujube showed obviously seasonal characteristics. The more serious drought stress the wild jujube was subjected to, the earlier performance of the influence of drought stress on photosynthesis rate showed. And no matter how the photosynthesis rate and transpiration rate changed with environmental weather factors, the WUE of wild jujube decreased under drought stress condition. The respiratory rate, light compensation point and light saturating point decreased under drought stress, while the light saturating point dropped less under moderate drought stress. The light intensity requirement of wild jujube was not high. Light intensity under 1200μmol photons·s-1 was more beneficial to its growth.It was also found that the water potential decreased under drought stress. The free proline content increased under drought stress. The protective enzyme activities of SOD, POD, CAT and APX all increased, but to different degrees. They reached the peak 2-4 d after drought stress. Nevertheless, wild jujube was still seriously damaged by drought stress, which was reflected by increased MDA content and cell membrane permeability.One-year-old wild jujube seedlings cultivated in pots were treated with drying and re-watering cycles. The physiology characteristics were analyzed. Results showed that repeated drought stress could enhance the drought resistance of wild jujube. The enhanced antioxidant activity was the main mechanism. Wild jujube plants exposed to drought stress for the first time could not recover their photosynthesis and transpiration function at the beginning of re-watering stage.The tea processing technology of wild jujube was studied by using central composite design and response surface analysis. The tea processing technology of wild jujube involved picking, spreading, drying in the air, deactivating of enzyme, rolling, drying and spreading again, among which temperature of deactivation of enzyme was 120℃, the time of deactivation of enzyme was 5 min, the rolling time was 10 min, and the temperature of drying was 60-90℃.