木霉缓解外源草酸对黄瓜幼苗毒害的作用研究

Detoxification Effect of Trichoderma on Exogenous Oxalic Acid to Cucumber Seedlings

为了研究木霉(Trichoderma)在缓解外源草酸对植物毒害上的作用,本研究以黄瓜幼苗为试材,设置10、20、30、50、80 mmol/L草酸及相应的接种木霉处理,以清水、PDB培养基和木霉发酵滤液处理为对照,通过表型观察和中毒指数计算分析其对黄瓜幼苗生长的影响,同时分析叶片中抗病和抗氧化酶包括苯丙氨酸解氨酶(PAL)、多酚氧化酶(PPO)、过氧化氢酶(CAT)和超氧化物歧化酶(SOD)活性的变化。结果表明,草酸浓度低于30 mmol/L时,接种木霉明显缓解了草酸对黄瓜幼苗的毒害作用。相较于PDB培养基对照,添加不同浓度的草酸均显著提高了两种抗病相关酶(PAL和PPO)的活性,显著降低了SOD活性,CAT活性除20、80 mmol/L浓度下显著升高外其余差异不显著;在相应浓度草酸处理中接种木霉后,PAL活性显著降低,PPO活性除在30、50 mmol/L浓度下显著升高外其余均显著降低,SOD活性均不同程度地降低,CAT活性除在10、50 mmol/L浓度下无显著差异外其余均显著降低。综上,接种木霉能有效缓解低浓度(10~20 mmol/L)外源草酸对黄瓜幼苗的毒害,对系统抗性酶活性产生了不同的影响,这为进一步研究木霉对植物响应外源草酸胁迫的影响提供了参考。

In order to study the effect of Trichoderma on detoxifying exogenous oxalic acid(OA) in the plant,the experiment was conducted with cucumber seedlings as test materials which were treated with OA at 10,20,30,50 and 80 mmol/L and corresponding Trichoderma inoculation treatments.The water treatment,PDB medium treatment and only Trichoderma fermentation filtrate treatment were used as control groups.Their effects on growth of cucumber seedlings were analyzed by phenotype observation and poisoning index calculation,and the variation of PAL,PPO,CAT and SOD activities in leaves were also analyzed.The results showed that the toxic effect of OA on cucumber seedlings was obviously alleviated by inoculating with Trichoderma when the OA concentration was lower than 30 mmol/L.Compared with PDB treatment,different concentrations of OA significantly increased the activities of the two disease-resistance-related enzymes PAL and PPO,and significantly decreased the SOD activity;there was no significant differences in CAT activity except significant increase at 20 and 80 mmol/L OA.After inoculation with Trichoderma in the corresponding OA treatments,the PAL activity decreased significantly,the PPO activity decreased significantly except for increasing at 30 and 50 mmol/L of OA,the SOD activity decreased to different extents,and the CAT activity decreased significantly except at 10 and 50 mmol/L concentrations.In conclusion,inoculation with Trichoderma could effectively detoxifying oxalic acid to cucumber seedlings,and had different effects on antioxidant enzymes.These results could provide references for further research of Trichoderma influencing the response of the plant to exogenous OA.