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为进一步揭示不同基因型水稻耐盐性差异的生理机制,探明盐胁迫初期根部激素ABA对水稻耐盐性的调控机理。于2009年10月～2010年2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。结果表明,盐胁迫条件下耐盐基因型(IR651)相对于敏感基因型(IR29)保持了更高的生物量,“稀释”了植株体内盐分离子的浓度而减轻盐胁迫。两水稻基因型盐胁迫条件下对盐分的总吸收量并无明显差异,IR651根部较强的耐盐性和较大的生物量可以储存更多的Na+,从而减少Na+向地上部的转运量。盐胁迫初期IR651根部ABA的大量合成是叶片蒸腾速率显著降低的主要原因,从而抑制了盐分离子的大量吸收,大大减轻了盐胁迫初期大量盐分离子吸收对植株造成的不可恢复性伤害。可见,盐胁迫条件下耐盐基因型较大的生物量、根的生理特性以及盐胁迫初期ABA的特有调控都大大增强了其耐盐胁迫性能,是耐盐基因型相对敏感基因型有更强耐盐胁迫能力的重要原因。
In order to further reveal the physiological mechanism of salt tolerance difference in different genotypes of rice, the regulation mechanism of salt tolerance of root ABA on salt tolerance in early stage of salt stress was explored. From October 2009 to February 2010, hydroponic experiments were carried out in the International Rice Research Institute climate chamber which strictly controlled the supply of water, temperature, light and nutrients. The results showed that the salt tolerant genotype (IR651) maintained a higher biomass relative to the susceptible genotype (IR29) under salt stress, which “diluted” the concentration of salt ions in the plant and reduced the salt stress. Under the salt stress of two rice genotypes, there was no significant difference in the total uptake of salt. The stronger salt tolerance and the larger biomass of IR651 root could store more Na +, thus reducing the Na + translocation to the shoot. The bulk synthesis of ABA at the early stage of salt stress was the main reason for the significant decrease of leaf transpiration rate, which inhibited the large absorption of salt ions and greatly reduced the irreversible damage to plants caused by salt ion absorption in the early stage of salt stress. It can be seen that under salt stress, the biomass of salt tolerant genotypes, the physiological characteristics of roots and the special regulation of ABA at the early stage of salt stress all greatly enhanced the salt tolerance of the salt tolerant genotypes, Salt stress resistance of the important reasons.