生长素介导海藻酸钠寡糖调控水稻对镉胁迫的抗性

Auxin Mediates the Regulation of Alginate Oligosaccharides on Rice Resistance to Cadmium Stress

采用生长素运输抑制剂,探讨生长素是否介导海藻酸钠寡糖(AOS)缓解水稻镉(Cd)胁迫。结果表明,Cd胁迫明显抑制水稻幼苗的生长发育,表现在苗长、地上部生物量和地下部生物量均有不同程度降低;AOS预处理可显著提高水稻植株超氧化物歧化酶(SOD)、过氧化物酶(POD)和抗坏血酸过氧化物酶(APX)活性,降低O_2^(-·)产生速率,使SOD/O_2^(-·)、SOD/POD、SOD/过氧化氢酶(CAT)和POD/O_2^(-·)的比值增加,丙二醛含量下降,苗长、根长及生物量均有一定程度恢复,但会造成H_2O_2在体内有一定累积。生长素信号被阻断后,AOS预处理(Cd+AOS+Y)对水稻Cd胁迫的缓解效应明显受到削弱,表现为苗长、根长等生长指标和抗氧化酶活性均较生长素信号未阻断处理(Cd+AOS)有所降低,补加外源生长素后(Cd+AOS+Y+NAA),各项指标又有所增加,该结果初步表明,生长素信号介导AOS调控水稻对Cd胁迫的抗性。

Auxin transport inhibitor was used to explore whether auxin mediates modification of cadmium （Cd） toxicity by alginate oligosaccharides （AOS） in rice （ Oryza sativa L. ） ,from the view of the growth and antioxidant metabolism. The results showed that Cd stress significantly inhibited the growth of rice seedlings. The seedling length, aboveground biomass and belowground biomass were reduced to different degrees. Under the condition of Cd stress, AOS pretreatment significantly improved the activities of superoxide dismutase （ SOD ）, peroxidase （ POD ） and ascorbate peroxidase （APX） in rice, and reduced 02＂ production rate. These changes resulted in the increases of SOD/O2＂ , SOD/POD, SOD/catalase （CAT） and POD/OZ＇ and the decrease of malondialdehyde content. Seedling length ,root length and bio- mass increased to some extent, but H2 02 had a certain accumulation in rice. After auxin signal was blocked, the amelio- rating effects of AOS pretreatment （ Cd ＋ AOS ＋ Y） on Cd stress was weakened in rice. Compared with the treatments of non-blocked auxin signal （Cd ＋ AOS） ,growth indicators （such as seedling length,root length） and the activities of an- tioxidant enzymes was reduced ; After adding exogenous auxin （ Cd ＋ AOS ＋ Y ＋ NAA） , various indicators had been im- proved in different extent. These results preliminarily showed that auxin mediated the regulation of AOS on rice resist- ance to Cd stress.