玉米苗中DIMBOA与几种酚酸类物质抑菌活性比较

本文从室内培养的7日龄玉米幼苗中提取、分离、鉴定了抗性次生化合物丁布(2,4-d ihydroxy-7-m ethoxy-2H-1,4-benzoxazin-3(4H)-one,D IMBOA),并就该物质对玉米纹枯病病原菌立枯丝核菌(Rhizoctonia solani)的活性与三种酚酸类物质(阿魏酸、对羟基肉桂酸和咖啡酸)进行了离体比较研究。结果表明,丁布(D IMBOA),对立枯丝核菌有很强的生物活性,在浓度为50μg/mL时即可抑制立枯丝核菌菌丝的生长,抑制率为18.52%。阿魏酸、对羟基肉桂酸和咖啡酸,这三种酚酸在浓度250μg/mL时对立枯丝核菌菌丝的生长有抑制作用,抑制率分别为26.30%、8.50%和6.30%。不仅如此,丁布与对羟基肉桂酸之间、以及三种酚酸两两组合之间还存在一定的协同作用。在浓度相等的情况下,丁布与对羟基肉桂酸的等量混合液的抑菌率显著高于这两种物质单独存在时的抑菌率之和;同样,对羟基肉桂酸与阿魏酸的等量混合液的抑菌率比单一的对羟基肉桂酸溶液的抑菌率高18.89%,比单一的阿魏酸溶液的抑菌率高13.33%;对羟基肉桂酸与咖啡酸的等量混合液,抑菌率比两者单独试验时分别高9.63%和14.83%;阿魏酸与咖啡酸的混合液,抑菌率比两酸单独试验时分别高11.48%和22.23%。这一结果提示植物体内产生适当比例不同次生化合物的组合对植物抗病性的提高是至关重要的。

Antifungus Activity of DIMBOA from Maize Seedlings Compared with Several Phenolic Acids

The main fungal toxic secondary compound of 2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one (DIMBOA) was extracted from 7-day-old maize seedlings.Its antifungus activity against Rhizoctonia solani was tested in culture dishes and compared with that of other three phenolic compounds in maize including,ferulic acid,p-hydroxycinnamic acid and caffeic acid.The results showed that DIMBOA inhibited the hyphae growth of R.solani by 18.52% at the concentration of 50 μg/mL.The other three phenolic compounds also inhibited the hyphae growth of R.solani by 26.30%,8.50%and 6.30%respectively at the concentration of 250 μg/mL.Furthermore,there were synergistic effects between DIMBOA and p-hydroxycinnamic acid,and among the three phenolic acids on the inhibition of the hyphae growth of R.solani.With the same concentration,the inhibition rate of the mixture with 1:1 ferulic acid and p-hydroxycinnamic acid increased 18.89%when it was compared with that of p-hydroxycinnamic acid alone or increased 13.33%when it was compared with that of ferulic acid alone.With the same concentration,inhibition rate of the mixture with 1:1 p-hydroxycinnamic acid and caffeic acid increased 9.63%or 14.83%when it was compared with that of p-hydroxycinnamic acid alone or caffeic acid alone.The inhibition rate of the 1:1 mixture of ferulic acid and caffeic acid was 11.48%or 22.23%higher than that of ferulic acid or caffeic acid separately.Even more,the inhibition rate of the mixture of any two compounds was higher than the sum of the inhibition rate of the two compounds.The results infered that proper ratio of different secondary compounds in plant was impotant for plant disease resistant.