茉莉酮酸甲酯对水稻化感物质的诱导效应

Inducible effects of methyl jasmonate on allelochemicals from rice

在室内和田间条件下 ,外源茉莉酮酸甲酯均能显著地诱导水稻化感物质的合成 ,而且这种诱导效应与施用茉莉酮酸甲酯的浓度和诱导时间显著相关。 0 .4 m mol/L浓度和处理后 4 8h,茉莉酮酸甲酯对水稻化感物质的诱导效应最强。同样 ,不同的水稻品种对茉莉酮酸甲酯的诱导响应也有显著差异。水稻化感品种 PI312 777和丰华占在茉莉酮酸甲酯的诱导下能很快合成大量的化感物质 ,而水稻非化感品种华粳籼的化感物质的含量虽也有所增加 ,但达不到能显示化感作用的浓度。进一步实验证明 :茉莉酮酸甲酯在处理 4 8h后虽能诱导水稻品种合成大量的化感物质 ,但这一诱导效应并不能长期维持。研究揭示 :水稻化感物质的合成可在外部因子的作用下动态变化 ,这对揭示和充分利用水稻的化感作用机制有重要意义。

Methyl jasmonate is a signaling molecule that is mediated through air between plants. It plays important role in activating self-defensive system and induces secondary metabolites production in plants. One of the most important defensive systems in allelopathic rice varieties against associated weeds is to produce and release allelochemicals. Therefore, inducible effects by methyl jasmonate on rice allelochemicals production were investigated under both laboratory and field conditions. The results demonstrated that rice allelochemicals (m-arabinose-pentadecanyl-resorcinol, m-arabinose- pentadecenyl-8-resorcinol, 7-xylose-luteolin, 3-glucose-hydroxmaic acid and 3-glucose -7-methoxy-hydroxamic acid) productions were elicited by exogenously applied methyl jasmonate in rice leaves. This inducible effect was dose-dependent and inducible period-dependent. The application of 0.4mmol/L methyl jasmonate effectively induced to synthesize significant amounts of allelochemicals in allelopathic rice plants in the laboratory and field. The levels of allelochemicals increased rapidly in methyl jasmonate-elicited rice leaves and reached maximum values in 48h after treatments. Furthermore, the inducible response to allelochemical production depended on different rice varieties. Allelopathic rice varieties, PI312777 and Fenghuazhan, could be induced to synthesize a large amount of allelochemicals by methyl jasmonate at different concentrations. However, allelochemicals amounts of non-allelopathic Huajingxian were slightly increased and could not reach the levels to express its allelopathic potential. In addtion, the inducible effects by methyl jasmonate on rice allelochemicals also were time-dependent and could not be maintained for a long period. As a result, rice allelochemical production began 12h after treatment with methyl jasmonate and required 48h for obtaining a maximum accumulation, and then allelochemical amounts were gradually reduced. The results showed that the accumulation of rice allelochemicals in response to exogenous methyl jasmonate was dynamic, and the allelochemical production in rice plant could be triggered by exogenously applied methyl jasmonate. This finding suggests that allelochemical elicitation by exogenously applied methyl jasmonate is worthwhile in future study for the understanding of allelopathic rice variety against associated weeds.