外源根系分泌物对紫花苜蓿根瘤菌共生体系的影响

Effects of Exogenous Root Exudates on Symbiosis of Alfalfa and Rhizobium

为筛选诱导紫花苜蓿(Medicago sativa L.)生长结瘤的适宜外源根系分泌物,本试验利用木犀草素、茉莉酸甲酯、季酮酸以及水苏碱+葫芦巴碱混合物5种外源根系分泌物(共生信号物质)对苜蓿根瘤菌ACCC17617(A17)和ACCC17631(A31)诱导,结合室内试验与田间试验,分析外源根系分泌物对根瘤菌的诱导效应,并对苜蓿结瘤特征及生长性状测定,研究外源根系分泌物对紫花苜蓿接种根瘤菌共生体系的影响。结果表明:5种外源根系分泌物能有效提高苜蓿的结瘤数、生物量、蛋白含量以及受诱导的根瘤菌占瘤率。不同物质(或组合)对菌株与苜蓿共生结瘤和苜蓿生长的影响不同,室内条件下木犀草素对苜蓿的生长发育有较好的促进效果。田间试验条件下,经外源根系分泌物诱导后,根瘤菌A31的田间竞争力大于根瘤菌A17。

In order to screen the extraneous root exudates for inducing growth and nodules of alfalfa,we analyzed the induction effect of five root exogenous exudates(symbiotic signaling substances)including Luteolin,Methyl Jasmonate,Tetronic acid and Stachydrine+Trigonelline mixture on alfalfa rhizobia ACCC17617 and ACCC17631 and analyzed the characteristics of nodule formation and the growth traits of alfalfa,both in laboratory and the field.The results showed that five exogenous root exudates effectively increased the nodule number,biomass and protein content of alfalfa,as well as the incidence of rhizobia.Different substances(or combinations)had different effects on the growth of alfalfa and bacterial strains.Luteolin promoted the growth and development of alfalfa.In the field experiment,the competitiveness of A31 increased more after adding root secretion than that of A17.