马铃薯根系分泌物成分鉴别及其对立枯丝核菌的影响

Identification of chemicals in root exudates of potato and their effects on Rhizoctonia solani

采用自制根盒收集了苗期和现蕾期连作5年和轮作马铃薯的根系分泌物,并用GCMS进行了鉴定.结果表明:在苗期和现蕾期,马铃薯根系分泌物中糖类物质含量最高,其次为有机酸类,且有连作马铃薯根系分泌物中糖含量下降、有机酸含量升高的趋势.连作马铃薯苗期和现蕾期根系分泌物中棕榈酸相对含量分别为0.94%和1.4%,邻苯二甲酸二丁酯相对含量均为0.15%;轮作马铃薯苗期和现蕾期根系分泌物中棕榈酸相对含量仅为0.15%和0.2%,邻苯二甲酸二丁酯未检出.轮作和连作马铃薯根系分泌物都可促进立枯丝核菌的生长,连作马铃薯根系分泌物的作用更显著.模拟试验表明:棕榈酸和邻苯二甲酸二丁酯均可明显促进立枯丝核菌生长,说明马铃薯根系分泌物对立枯丝核菌的促进作用与分泌物中含有棕榈酸和邻苯二甲酸二丁酯有关.

This study was conducted to identify chemicals in root exudates and their effect on Rhizoctonia solani in potato cropping systems. Root exudates were collected from the fields with 5 years of continuous potato cropping in comparison with rotational cropping of potato and other crops,using in-house made root boxes at the seedling and squaring stages. Chemicals in the root exudates were identified using the GC-MS method. The results showed that glucide concentration was the highest in the root exudates,followed by organic acids. Compared with the rotational cropping,the continuous cropping significantly decreased the glucide content and increased the content of organic acids in the root exudates. The contents of almitic acid in root exudates under continuous cropping was 0.94% at seedling stage and 1.4% at squaring stage,the dibutyl phthalate was 0.15%,whereas under rotational cropping,those values were decreased to 0.15%,0.2%,and being negligible,respectively.The root exudates promoted the growth of R. solani,especially under continuous potato cropping.The simulation test showed that the palmitic acid and dibutyl phthalate in root exudates could promote the growth of R. solani.