| Ramie is one of the perennial herbaceous plants and textile fiber crops. Studies on stress resistance of ramie become increasingly important, among which cultivation of drought resistance is an important field of research. In order to evaluate the ability of drought resistance of different ramie cultivars, physiological and biochemical indexes closely related to drought were screened. We used15ramie cultivars as tested materials, planted them in pots under drought and normal treatment respectively and measured the dry biomass of the aerial part of ramie, malondialdehyde content, peroxidase activity, proline content, net photosynthesis rate, stomatal conductance, intercellular carbon dioxide concentration, transpiration rate, growth rate and SPAD value. By the analysis of the data, we identified drought resistance of the15ramie cultivars and screened physiological and biochemical indexes closely related to drought tolerance. Meanwhile, we explored the dynamic variation of relative moisture content, malondialdehyde content, peroxidase activity, proline content of ramie leaf under drought stress using Huazhu No.4.The results were shown as below:1.The dry biomass of the aerial part of ramie was calculated as a drought index, which was used to evaluate drought resistance of different cultivars of ramie. The results showed:Niuerqing, Huazhu No.5and Guangxiheipidou belong to middle-drought-tolerant cultivars; Jiangxitongpiqing, Jiangxilufan, Xiangzhul, Bailiziqing and Enshijigubai belong to drought-tolerant cultivars; Xiushuima, Luzhuqing, Baxi No.2, Zixingma, Qianzhu No.1, Huangkezao and Xiyelv belong to drought-sensetivecultivars. We used subordinate function value method to analysis physiological and biochemical indexes closely related to drought resistance, and then drought resistance of different ramie cultivars was determinated by the comprehensive evaluation value.The results showed:Niuerqing, Huazhu No.5and Guangxiheipidou belong tomiddle-drought-tolerant; Jiangxilufan, Jiangxitongpiqing, Enshijigubai, Luzhuqing, Xiangzhu No.1, Baxi No.2, Zixingma and Bailiziqing belong to drought-tolerant; Xiushuima, Qianzhu No.1, Huangkezao and Xiyelv belong to drought-sensetive. 2. The dry biomass of the aerial part of ramie, malondialdehyde content, peroxidase activity, proline content, net photosynthesis rate, stomatal conductance, intercellular carbon dioxide concentration, transpiration rate, growth rate and SPAD value were measured under water stress. The results showed:malondialdehyde content, peroxidase activity, proline content of ramie leaf increased under water deficiency; net photosynthesis rate, stomatal conductance, intercellular carbon dioxide concentration, transpiration rate, growth rate reduced under water stress. The fluctuate extent of the above indexes significantly differed among different ramie cultivars, reflecting their various ability of drought tolerance.3. The correlation analysis between the physiological and biochemical indexes and the drought index was conducted and the results showed:intercellular carbon dioxide concentration and SPAD value didn’t significantly relate to drought index, all other physiological and biochemical indexes exhibited significant relationship to drought index. Proline content, net photosynthesis rate and stomatal conductance were extremely related to drought index. The correlation coefficient is-0.767,0.813and0.709respectively, which makes these indexes possible to evaluate the ability of drought tolerance of ramie.4. Leaf relative moisture content, malondialdehyde content, peroxidase activity, proline content of Huazhu No.4were measured. The results showed:with the degree of drought stress extent deepening, leaf relative moisture content was downtrend; malondialdehyde contentshowed an increasing tendency; peroxidase activity risedat first, reached the peak at the3rd day of stress and then reduced; proline contentincreased rapidlyafter3days of stress. |
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