生物及非生物诱导因子对水稻白叶枯病的诱导抗性及其与活性氧代谢的关系

Resistance Induced by Biotic and Abiotic Inducers to Rice Bacterial Blight (Xanthomonas oryzae pv.oryzae) and Its Relation to Active Oxygen Metabolism in Rice Seedlings

以对白叶枯病高抗的水稻品种余水糯和高感的水稻品种浙辐802为材料，于2叶期用Tiron、Paraquat（PQ）和稻白叶枯病菌弱毒每株75－l进行诱导处理，测定诱导处理后3、24、48、72h叶中超氧化物歧化酶（SoD）活性、o2产生速率及丙二醛（MDA）含量的动态变化，并于3叶期用白叶枯病菌强毒株76－25进行挑战接种，结果表明：75－1和PQ均诱导两品种产生了系统抗性，并使诱导叶中o2产生速率和MDA含量增加。75－1使o2产生速率在24h达峰值，比对照升高3o．6％（余水糯）和25.3％（浙辐8o2）；而PQ使o2产生速率在24～72h维持较高水平，比对照升高49.4％（余水糯）和39．7％（浙辐8o2）。MDA含量的变化晚于o2产生速率的改变，在72h达最高值。75-1使SoD活性降低，并在24h达最大降幅；而PQ使SoD活性升高，并在48h达峰值。Tiron使PQ和75－l的诱导效果减弱，并使75－l对余水糯和浙辐8o2的互作由非亲和性互作转变为类似亲和性互作，导致侵染斑的形成。

Two rice cultivars,Yushuinuo and Zhefu 8o2, with high resistance and susceptibility to rice bacterial blight respectively were used as materials. Their second leaves were pre-treated at the two-1eaf stage with paraquat(PQ),a strain of Xanthomonas oryzae pv. oryzae(Xoo )75-1 with weak viru1ence and Tiron (4, 5-dihydroxy-l, 3-benzene-disufonic acid)which can specifically react with o2. The challenge inoculation with a strain 76-25 of high viruIence was used at the three-leaf stage. The results showed that pre-treatment with PQ and 75-1 strain induced systematic resistance to strain 76-25, and increased the rate of o2-generation and MDA (malondialdehyde) content in the induced leaves. The change of o2 -generating rate was greatest at 24 h to 72 h after induction with PQ. The changes of MDA content in the induced leaves were later than that of o2-generating rate and the greatest was at 72 h after induction with both PQ and 75-l strain. However the activities of super oxide dismutase (SoD) in the induced leaves decreased after induction with 75-l strain,but increased after induction with PQ. Tiron showed a negative effect on the induced resistance to Xoocaused by 75-l strain and PQ. lt was specially found that the incompatible interaction between 75-1 strain and two rice cultivars turned into a similar compatible interaction when 75-l strain added o2 scavenger Tiron as an inducer.