K^+,Ca^(2+)和Mg^(2+)对不同水稻(Oryza sativa L.)基因型苗期耐盐性的影响

The Salinity Tolerance of Rice (Oryza sativa L.) Genotypes as Affected by Nutrients (K^+, Ca^(2+) and Mg^(2+)) at Seedling Stage

【目的】进一步探明盐胁迫条件下营养元素K+、Ca2+和Mg2+对苗期不同水稻基因型耐盐性的影响差异,为明确作物耐盐胁迫的生理机制、提高作物耐盐胁迫能力提供参考。【方法】于2009年1—4月在严格控制水、温、光和营养元素供应的国际水稻研究所人工气候室进行水培试验,比较研究营养液中K+、Ca2+和Mg2+浓度的变化对不同水稻基因型苗期耐盐性的影响。【结果】在盐胁迫条件下(100mmol·L-1NaCl),耐盐基因型(FL478和IR651)与盐敏感基因型(IR29和Azucena)相比,植株体内有较低的Na+含量和Na+/K+、Na+/Ca2+、Na+/Mg2+比,有较高的K+含量,这些都是耐盐基因型耐盐胁迫能力高于盐敏感基因型的内在原因。盐胁迫条件下提高营养液中Ca2+和Mg2+的含量(60mg·L-1),可显著降低植株体Na+含量和Na+/K+、Na+/Ca2+、Na+/Mg2+比,明显减轻盐胁迫的危害,增强水稻耐盐胁迫能力,且Ca2+处理的效果优于Mg2+处理;而提高营养液K+含量对以上指标的影响远远小于Ca2+处理和Mg2+处理,这也是K+处理对水稻耐盐性影响相对不明显的内在原因。【结论】K+、Ca2+和Mg2+在植株体内的含量及其与Na+的比值变化都会影响水稻苗期耐盐性;适当提高水稻生长环境的Ca2+和Mg2+浓度可以明显增强植株耐盐胁迫能力,营养元素Ca2+的效果比Mg2+明显;而K+对水稻耐盐性的影响相对不明显。

【Objective】 The aim of the experiment was to study the salinity tolerance of rice （Oryza sativa L.） genotypes as affected by nutrients （K^＋, Ca^2＋ and Mg^2＋） at seedling stage, and supply some knowledge for further studies on the physiological mechanisms and improvement of crop salinity tolerance. 【Method】 A water culture experiment was conducted at phytotron in International Rice Research Institute （IRRI） during Jan.-Apr. 2009, and the water supply, temperature, illumination and nutrients supplying, were strictly controlled to study on the effect of nutrients （K^＋, Ca^2＋ and Mg^2＋） concentrations on salinity tolerance of rice genotypes under salt stress at the seedling stage. 【Result】 The salt tolerant genotypes （FL478 and IR651）, when compared with the sensitive genotypes （IR29 and Azucena）, had lower content of Na＋ and lower ratios of Na＋/K^＋, Na＋/Ca^2＋ and Na＋/Mg^2＋, but had higher content of K^＋ in plant under salt stress （100 mmol·L^-1 NaCl）, that’s why tolerant genotypes have higher tolerant ability than sensitive genotypes. The content of Na＋ and ratios of Na＋/K^＋, Na＋/Ca^2＋ and Na＋/Mg^2＋ in plant could be declined significantly, the effect of salt stress on plant growth was alleviated significantly, the salinity tolerance of rice was improved significantly and the influence of Ca^2＋ treatment was higher than Mg^2＋ treatment, when the concentrations of Ca^2＋ and Mg^2＋ in culture solution were increased （60 mg·L^-1）. However, the effect of K^＋ treatment on the above parameters was lower than Ca^2＋ and Mg^2＋ treatmentsrespectively, that’s why the effect of K^＋ treatment on salinity tolerance of rice is not significant. 【Conclusion】 The salinity tolerance of rice can be affected by the changes of nutrients contents and nutrients ratios of plant tissues. Salinity tolerance of plant can be improved significantly by properly increasing the concentrations of available plant nutrients （Ca^2＋ and Mg^2＋） in culture solution, and the effective of Ca^2＋ is higher than Mg^2＋ significantly, but the effect of K^＋ on salinity tolerance of rice is not significant.