Abstract:

In order to select physiological indices closely related to salt tolerance of cotton and provide theoretical basis for salt tolerance identifying in cotton seedling stage. The changes of relative value of seven physiological indices on 0, 5, 10, 15 days after salt stress were studied in seeding through planting experiment in plastic box. Four cotton breeds were used as materials. The indices included the relative water content, membrane permeability, dissociative proline content, malondialdehyde content and K+/Na+ ratio. The datum were analyzed by means of variance analysis, principal components analysis and membership function method. There was significant difference on relative value of all indices between the treatment and the control on the fifth day after salt stress; three indices, K+/Na+ ratio, relative water content and membrane permeability, were selected, which had close relation to salt tolerance; the salt tolerance capability of four cotton breeds decreased in order of zhimian3, zhongmiansuo35, lumian6, zhongmiansuo12. The fifth day after salt stress is the best appraisal time, the selected indices can be represent all information from seven indices, and its evaluation results have a high correlation with the evaluation results of index of salt in technical standard of evaluation for Salt Tolerance on cotton, so they can be used for comprehensive evaluation of cotton in seeding.