硅对水稻病程相关蛋白活性和酚类物质含量的影响及其与诱导抗性的关系

Influences of silicon on activities of pathogenesis-related proteins and contents of total soluble phenolics and lignin in rice leaves infected by Magnaporthe grisea and its relation to induced rice blast resistance

为阐明硅提高水稻抗稻瘟病的生理机制,采用室内溶液培养试验,研究了硅对接种稻瘟病菌后水稻叶片的几丁质酶和β-1,3-葡聚糖酶活性以及总可溶性酚和木质素含量的影响。结果表明,接种稻瘟病菌能诱导几丁质酶活性的快速上升,不施硅处理的几丁质酶活性在第2 d达到第一个峰值后就开始下降,而施硅处理的几丁质酶活性则继续上升,直到第4 d才开始下降,从第4～8d显著高于不施硅处理。β-1,3-葡聚糖酶活性在接种后的第4 d之前均上升缓慢,处理间差异不显著;第4 d后开始上升,到第8 d达到最大值;不施硅处理上升更快,显著高于施硅处理。接种稻瘟病菌能诱导水稻叶片总可溶性酚含量快速上升,施硅处理和不施硅处理分别在接种后的第3 d和第4 d达到峰值,并开始快速下降;施硅能显著提高总可溶性酚含量。水稻叶片中的木质素含量在接种后的第1d快速上升,并维持较高水平,施硅处理显著高于不施硅处理;但在感病后期（第6 d）,施硅处理开始显著低于不施硅处理。

A series of hydroponics experiments were performed in controlled rice- Magnaporthe grisea pathosystem to study the effects of silicon （Si） on activities of chitinase and β- 1,3-glucanase and contents of phenolics and lignin. Regardless of silicon amendment, exochitinase and endochitinase activities had entirely consistent trend, and both rapidly increased after inoculation. Chitinase activity in Si-plants reached the first peak at 2 d after inoculation, and thereafter began to decline. However, chitinase activity in Si ＋ plants continuously increased until 4 d after inoculation and was significantly higher than in Si-plants from 4 d to 8 d. By contrast, silicon application decreased β - 1, 3-glucanase activity in rice leaves infected by M. grisea. Contents of total soluble phenolics and lignin in Si ＋ plants were significantly higher than in Si-plants. However, lignin content in Si ＋ plants was significantly lower than in Si-plants at 6 d after inoculation. These findings support the hypothesis that silicon is closely involved in induced resistance to rice blast.