Characteristics Of Drought Tolerance And Evaluation Indexes Of 3 Species Of Musa Spp. In Seedlings Stage

Banana, one of China four major fruits, is tropical and subtropical large herb, which is the most high-yield fruit and crop of the world. Banana is rich in resources, and has abundant varieties. The objective of the research is to explore the water physiology and photosynthetic characteristics of Banana, for pical and subtropical region banana plantation provide theoretical foundation and technology basis.We used current-year tissue culture plantlets(Musa AAA Giant cv.Baxi、Musa paradisiaca AA、Musa cavendishii ABB) as experimental materials to measure the growth characteristics, the water physiology and photosynthenic indexes of 3 Species under sustained soil water stress, and investigate the water physiology trends and diurnal variations of parameters of photosynthesis and transpiration. And at last we analyzed drought tolerance of banana seedlings with drought index evaluation system.The main results of the study were as follows,1. Water stress inhibited the normal growth of 3 species seedlings of significantly, and as the stress level increased, leaf shape and plant form were tremendously effected.2. Eight physiological and biochemical indicators, relative water content of soil, relative water content of leaves, proline, soluble sugar, soluble protein, SOD activity, MDA and relative conductivity, were used to identify the drought resistance of seedlings in the gradient of water stress. The results showed that as the increased of water stress, relative water content of soil and relative water content of leaves declined. Content of proline, MDA and relative conductivity increased all the time. however, soluble sugar and soluble protein increased first and then decreased. And SOD activity declined and then increased as the increase of water stress. Compared with Baxi banana and Huangdi banana the main indexes of Fen banana were diverse, and the results showed strong drought tolerance.3. Photosynthesis of 3 kinds of banana seedlings decreased when water stress was severity. The increas of chlorophyll content were M type as the water stress, carotenoid appeared certain rise. As the stress time extension, the net photosynthetic rate, transpiration rate and stomatal conductance were decreased, intercellular CO2 concentration increased as the rise of water stress. Increase of intercellular CO2 concentration was caused by tomatal limitation. WUE of Baxi banana and Huangdi bananan showed∧type, which indicated that two kinds of banana seedlings started the drought resistance mechanism earlier, but they didn’t last a long time. In general, in photosynthesis, the photosynthetic indicators of Fen banana changed slowly, which indicated Fen banana has most resistant to drought. 4. The use of fuzzy membership function of three kinds of banana seedlings under drought adaptability and productivity compared drought. Three kinds of banana seedlings order of drought resistance of plantain> Brazil banana> emperor banana.The adaptability and productivity of the three seedlings under water stress were contrasted and compared through subordination function of fuzzy mathematical analysis.The drought-resistant ability of three seedlings was listed in descending order as follows, Fen banana>Baxi banana>Huangdi bananan.