低温与氮耦合对水稻内源激素含量的影响

Effects of low temperature and nitrogen coupling on endogenous hormones of rice

【目的】探究不同耐冷氮高效水稻材料内源激素代谢特点,以阐明氮营养对提高水稻耐冷性的调节机理。【方法】以水稻近等基因系耐冷氮高效I16和冷敏氮低效I67为材料,采用水培试验,研究人工气候室模拟低温胁迫与4个氮肥水平(10,20,40和60 mg/L)耦合对水稻根、叶中内源激素吲哚乙酸(IAA)、细胞分裂素(CTK)、赤霉素(GA)、脱落酸(ABA)含量的影响及其互作效应。【结果】随水稻生育进程,根和叶中IAA、CTK、GA含量呈先升高后降低的趋势,在开花期达到峰值,ABA含量在成熟期达峰值。水稻根和叶中IAA、CTK、GA含量随施氮水平增加而升高,ABA则相反;在相同施氮水平下,低温抑制IAA、CTK、GA合成,促进ABA升高,4种激素含量呈现I16高于I67,叶高于根。低温与中氮耦合对水稻根和叶中IAA、CTK、GA的调控为正效应,低温与高氮耦合调控ABA为负效应,中氮可使水稻维持较高内源激素含量,这是增强水稻耐冷性的内在机理之一。【结论】在低温和氮肥耦合下,维持根叶中较高的IAA、CTK、GA、ABA含量,以及施氮对根、叶激素耦合效应的差异,是引起水稻耐冷性和氮素利用效率差异的重要生理调节因素。

【Objective】This experiment was conducted to understand the characteristics of endogenous hormone metabolism and elucidate the cold-regulatory mechanism induced to nitrogen nutrition of rice.【Method】Two isogenic lines I16(cold-tolerant and nitrogen high-efficient)and I67(cold-sensitive and nitrogen low-efficient)were selected and the effects of low temperature and nitrogen coupling on endogenous hormones including indole-3-acetic acid(IAA),cytokinins(CTK),gibberellic acid(GA)and abscisic acid(ABA)in root and leaf during different growing stages were investigated.The hydroponic experiment was conducted with low temperature stress simulated artificial climate chamber and four nitrogen application levels(10,20,40 and 60 mg/L).【Result】IAA,CTK and GA contents in roots and leaves were promoted firstly and then reduced during rice growth with peaks at the flowering stage,and ABA reached the peak at the mature stage.IAA,CTK and GA contents in roots and leaves were increased with nitrogen application,while ABA content was opposite.Under same nitrogen application,low temperature inhibited the synthesis of IAA,CTK and GA,but promoted ABA.The four hormones showed the pattern of I16 higher than I67 and leaves higher than roots.The coupling effects of low temperature and normal nitrogen amount was positive for IAA,CTK and GA in roots and leaves,while low temperature and high nitrogen had negative effect for ABA.The normal nitrogen could maintain high endogenous hormones contents,which was one of the internal mechanisms to enhance cold tolerance of rice.【Conclusion】Under the coupling of low temperature and nitrogen fertilizer,the difference in high IAA,CTK,GA,ABA contents,coupling effects of nitrogen on hormones were responsible for differences in cold tolerance and nitrogen utilization efficiency of rice.