外源IBA对盐胁迫下水稻种子萌发的缓解效应

Alleviation Effect of Exogenous IBA on Rice Seed Germination under Salt Stress

为研究盐胁迫下外源IBA对水稻种子萌发特性的影响,以‘湘早籼45’为试验材料,设置4个不同浓度IBA浸种处理,研究其在不同盐胁迫下水稻种子萌发特性、抗氧化酶活性、丙二醛含量及可溶性蛋白含量的影响。结果表明,10μmol/L IBA浓度浸种处理能有效提高盐胁迫下水稻种子的发芽率,其在240 mmol/L盐胁迫下表现最为明显,同时,该浓度能够通过提高幼根的超氧化物歧化酶活性、降低丙二醛含量、增加可溶性蛋白含量从而缓解水稻种子受到的盐胁迫损伤。采用双因素方差分析发现,单一盐胁迫比单一IBA浸种浓度处理以及盐与IBA交互处理对水稻种子萌发的影响更为显著(P<0.05),同时,隶属函数综合评价可知水稻种子耐受性强弱为:盐与IBA交互处理>单一IBA浸种浓度>单一盐胁迫,且水稻种子受盐胁迫的临界梯度为40 mmol/L,IBA浸种处理的临界浓度为10μmol/L,交互处理的临界处理为40 mmol/L+10μmol/L。本研究为盐碱地地区的水稻栽培及抗逆育种提高了理论依据。

In order to study the effect of exogenous IBA on the germination characteristics of rice seeds under salt stress.The effects of four different concentrations of IBA soaking treatments on germination characteristics,antioxidant enzyme activities,MDA content and soluble protein content of rice seeds under different salt stress were studied.The results showed that seed soaking with 10μmol/L IBA solution could effectively improve the germination rate of rice seeds under salt stress,which was most obvious under 240 mmol/L salt stress.At the same time,it could alleviate the salt stress damage of rice seeds by increasing the activity of superoxide dismutase in roots,reducing the content of malondialdehyde and increasing the content of soluble protein.The results of two-way ANOVA showed that the effect of single salt stress on rice seed germination was more significant than that of single IBA soaking concentration and interaction of salt stress and IBA soaking concentration(P<0.05).The tolerance of rice seeds by comprehensive evaluation of membership function was as follows:interaction of salt stress and IBA soaking concentration>single IBA soaking concentration>single salt stress.The critical gradient of rice seeds under salt stress was 40 mmol/L,the critical concentration of IBA treatment was 10μmol/L,and the critical concentration of interaction treatment was 40 mmol/L+10μmol/L.This study provides a theoretical basis for rice cultivation and stress resistance breeding in saline alkali area.