外源硝普钠对镉胁迫下水稻种子萌发和幼苗生理特性的影响

摘要

In order to explore the ameliorating role of nitroprusside (SNP) on inhibition of seed germination caused by cadmium, the effects of 10, 30, 50, 100, 200 and 500 umol/L SNP on seed germination, seedling growth and physiological characteristics of rice were studied under cadmium stress. The results showed that the rice seed germination and seedling growth were significantly inhibited, the germination potential, germination index, vigor index, root and shoot length, and the activities of SOD, G-POD, APX and CAT significantly increased and the malondialdehyde (MDA) content significantly decreased under 100 umol/L cadmium stress compared to the control. Low concentration of SNP (≤ 100 μmol/L) could alleviate the inhibition effects of cadmium, under which the germination index, vigor index, root length, shoot length, root and shoot fresh weight, the activities of SOD, G-POD and APX of rice seedlings increased and the MDA content was significantly inhibited. Thirty umol/L SNP exhibited the most prominent alleviating effect, but the effect faded away with the increase of SNP concentration. When the concentration of SNP reached 500 umol/L, the toxicity effect of cadmium stress on the rice seedlings was aggravated.%为了探讨外源NO供体硝普钠对镉胁迫下水稻种子萌发受抑的缓解作用,研究10、30、50、100、200、500 μmol/L硝普钠(SNP)对镉胁迫(100 μmol/L)下水稻种子萌发、幼苗生长及相关生理指标的影响.结果表明,100μmol/L镉胁迫使水稻种子萌发和幼苗生长受到抑制,发芽势、发芽指数、活力系数、幼苗根长和芽长均显著降低,丙二醛(MDA)含量显著增加,SOD、G-POD、APX及CAT的活性明显受到抑制.较低浓度(≤100 μmol/L)硝普钠处理能提高镉胁迫下水稻种子的发芽指数和活力指数,增加幼苗的根长、芽长、根和芽鲜重,增强SOD、G-POD和APX活性并降低MDA含量,从而缓解镉的毒害效应,其中以30 μmol/L硝普钠处理效果最好.但随着硝普钠浓度的增大,其对镉胁迫的缓解效应逐渐减弱,当销普钠浓度达500 μmol/L时,会加剧镉胁迫的毒害作用.