Induction and Selection of Rice Mutants for Salt Tolerance

本研究的第一个目的是通过N-甲基-N-亚硝基脲（N-Methy-N-N-Nitroso Urea，MNU）处理水稻受精卵细胞，筛选出水稻耐盐变异体，并对其耐盐生理特性进行研究。CV.金梅兹盐渍后，测定了耐受变体地上部和根的钠（Na）浓度（以干物质计）。地上部Na含量低于Kinmaze。根中Na含量高于地上部。耐盐品种Nona Bokra的地上部和根中也有Na含量。从这些结果看来，耐受性变体更有效地将Na从芽中排除，如在Nona Bokra中观察到的。因此，有必要收集具有这种耐盐性的水稻变异体，为水稻耐盐性改良提供遗传资源。由于NaCl的程度托勒 ...更多信息 第二，本研究的目的是从籼稻品种IR 36的受精卵细胞经MNU处理获得的突变体中筛选耐盐性提高的变异体。在与Kinmaze相同的盐化营养培养液中检测M3种子的耐盐性反应。然而，由于IR 36的盐渍化条件不适宜，未能获得耐盐植株。因此，4叶期的幼苗用于耐盐筛选。用120 mM NaCl代替85 mM NaCl使营养液盐化，并且进一步通过在盐化3周后比较变体的幼苗生长与IR 36的幼苗生长来确定对盐度的响应。与IR 36相比生长良好的幼苗被认为是耐受的。耐受植物在正常营养液中生长至成熟。对405个菌株进行了耐盐性筛选，得到28个菌株，共50株。这些耐盐变异体将进一步筛选，以生产耐盐性改良水稻遗传资源。少

The first aim of the present study was to elucidate physiological properties responsible for the NaCl tolerance of a rice variant which was considered to be salt tolerant variant after screening mutants induced by the N-Methy-N-Nitroso Urea (MNU) treatment of the fertilized egg cells of rice Oryza sativa L. cv. Kinmaze. Sodium (Na) concentrations of shoot and root of the tolerant variant, on a dry matter basis, were determined after salination. Na content of the shoots was lower than that of Kinmaze. On the other hand Na content of root was high compared to that in the shoot. Similarly salt tolerant variety, Nona Bokra, showed Na contents in shoot and root. From these results it appeared that the tolerant variant was more effective in excluding Na from the shoot as observed in Nona Bokra. Therefore, it was concluded that the rice variant showing such salt tolerance response should be collected for providing genetical resources for improving salt tolerance. Since the degree of NaCl tole … More rance in the rice variant obtained so far was not enough, the second a aim of the present study was focused on screening variants with improved salt tolerance from rice mutants derived from MNU treatment of fertilized egg cells of Indica rice variety, IR 36. The salt tolerance response of the M3 seeds was examined in the same salinized nutrient culture solution as carried out in the case of Kinmaze. However, no tolerant plants could be obtained because the salinization conditions were not proper for IR 36. Therefore, the seedlings at 4 leaf stage were used for salt tolerant screening. The nutrient solution was salinized with 120 mM NaCl instead of 85 mM NaCl, and further the response to salinity was determined by comparing seedling growth of variants to that of IR 36 after 3 week salinization. Seedlings with good growth compared to IR 36 were considered as tolerant. Tolerant plants were grown to maturity in normal nutrient solution. The 405 strains were screened for salt tolerance and 28 strains (50 individuals in total) were obtained. These salt tolerant variants wil be given further screening for production of genetical resources of rice improved salt tolerance. Less