Effect Of Drought Stress And Seawater Cultivation On Growth And Physiological Characters Of Eggplant

The threat of drought to agriculture is one of the world problems. The vicious global climate change which threatens the agricultural production seriously causes the outbreak cycle of drought becoming short and the extent becoming serious, especially in recent year. It was an important, economical and effective drought-resistant measure that using the self drought-resistent ability of plant in order to eliminate threats of drought. But this measure depends on scientific and accurate evaluation to drought-resistance of plant, in other words, it should identify the ability of drought -resistant of varieties. So improving and using the drought-resistant of crop variety is an important matter. Vegetable is one of economic crops which need much water to irrigated, especially fruit-vegetable which has high requirements to water. So the evaluation Studies on drought-resistant of vegetable variety has important significance. Basing on high drought-resistant variety resources, exploring new available water resources is another effective measure without fail. If seawater which has huge resource could be used in agricultural production, it should have great strategic significance.This research using eggplant which belongs to the family of Solanaceae as experiment material studied the effect of drought stimulated by hypertonic solution on morphology, physiology and biochemistry character and anatomical structure in the stage of germination and adult firstly, then established evaluation method of eggplant drought-resistant. Using this method, we estimated the drought-resistant of wild eggplant and three cultivate varieties of eggplant. At last, the feasibility of measure that eggplant was grafted by wild variety as bickiron to improves development of eggplant under seawater was studied in order to exploring new available water resource. The result of experimentation in germination stage showed that the length of radicel was decreased significantly with CaCl₂ osmotic potential descended, while it increase firstly, and then descend with osmotic potential of PEG6000 and sucrose descended. Water potential and radicel activity fell down compared with the proline elevating when the osmotic potential of osmotic potentialosmotic of those three solutions descended. The radicel in PEG6000 and sucrose solutions became chin and ratio of cell length to cell width of radicel meristematic and elongation zone was higher than control. Oppositely radicel in CaCl₂ solutions became chick and ratio of cell length to cell width of radicel meristematic and elongation zone was 1:1. Indexes of radicel showed a highly significant correlation with the CaCl₂ solution concentration. So, CaCl₂ was the best osmotic substances of those three substances.According to above result, the effect of the morphology ,leaf water potential, leaf proline content, leaf soluble solids and root activity of four different eggplant(such as wild species Tolubamu and cultivated species Jingqie No 20, Jingqie No 1 and Jingqie No 10)were studied under water stress simulated by different concentrations of CaCl₂ solution. The results were as follows: With the increasing of water stress level, the growth of plant height, leaf area and stem diameter all were restrained under the water stress. Also, at the same condition, the leaves proline and soluble solids content tended to increase tended to increase, although the leaf water potential and root activity are reduced. Based on the analysising the change of these indexs, this research show that compared with Jingqie No 1 and Jingqie No 10, the growth of Tolubamu and Jingqie No 20 was restrained lightly, the increasing extent of leaves proline and soluble solids content was wider, and the lowered range of leaf water potential and root activity was lower. So and Jingqie No 20 were higher drought-resistanc than Jingqie No 1 and Jingqie No 10.Using wild-eggplant (Tolubamu) with strong drought resistance as rootstock, Zaoshujingqie No 1 with weak drought resistance as scion, the measure of grafting was to improve eggplant growth under seawater. The result show that the height, stem circumference and the biggest function leaf area of grafted eggplant are restrained less than own-root eggplant. Praline content of grafted plants was significantly higher than own-root eggplant, although Praline content of both of them increased under seawater. Malondialdehyde (MDA) content of the former was significantly lower than own-root eggplant, while the activities of superoxide dismutase (SOD) and peroxidase (POD) and catalase (CAT) were significantly higher than own-root eggplant. Meanwhile, the content of Na⁺ and the Na⁺/K⁺ in grafted eggplant was significantly lower than own-root eggplant. Based on these result, it could be concluded that the tolerance to seawater of grafted eggplant was stronger than that of own-root plants. So eggplant grafted by wilding could be the availability measure of using seawater.