外源硅对长豇豆锈病抗性的影响及其生理机制

Effect of exogenous silicon on resistance of asparagus bean rust and its physiological mechanism.

研究硅对不同锈病抗性品种锈菌胁迫下过氧化物酶(POD)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)、苯丙氨酸解氨酶(PAL)、超氧化物歧化酶(SOD)活性、丙二醛(MDA)含量和叶绿素荧光参数及呼吸特性的影响.结果表明,外源加硅使豇豆植株叶片中SiO2含量比对照提高36.42%.硅明显提高感病品种锈菌胁迫下抗氧化酶活性,降低MDA含量,延缓植株Fv/Fm、ΦPSⅡ和ETR的下降时间,减轻其下降程度;维持幼苗叶片较高的总呼吸活性(Vt)、替代途径能力(Valt)和替代途径实际运行活性(ρValt);未接种时外源硅对上述参数无明显影响(除POD、CAT外).硅可明显提高抗病品种接种锈菌后的POD、CAT、SOD活性,降低MDA含量,未接种时硅对上述参数无明显影响.同工酶分析表明,外源硅不能改变两品种的POD同工酶谱带.硅可显著降低感病品种的锈病病情指数,相对防效达31.7%.

The effects of root-applied silicon and inoculation with Uromyces vignae on the activities of peroxidase （POD）, eatalase （ CAT）, ascorbate peroxidase （ APX）, phenylalanine ammonia-lyase （PAL）, superoxide dismutase （SOD）, the content of malonyldialdehyde （MDA）, the chlorophyll fluorescence parameters and the respiration rate in the leaves of asparagus bean （Vigna sesquipedalis Wight. ） were investigated. The results showed that exogenous silicon significantly increased the content of SiO2, increased the activities of antioxidant enzymes, decreased the content of MDA, delayed and inhibited the decrease of Fv/Fm, ΦPS Ⅱ and ETR, maintained higher total respiration （Vt）, the alternative pathway capacity （Valt） and the alternative pathway activity （pValt） in the leaves of susceptible cuhivar inoculated with U. vignae. Without inoculation, exogenous Si couldn＇t affect those parameters above for susceptible variety except the activities of POD and CAT. For the resistant cuhivar, Si considerably increased the activities of POD, CAT and SOD, decreased the content of MDA in the inoculated leaves, but did not affect other parameters without U. vignae inoculation. Si did not change POD isoforms pattern in both cultivars. Si significantly decreased disease index and improved the ability of resistance to rust for the susceptible variety.