不同苜蓿—根瘤菌结瘤固氮能力变异的研究

Study on Variation of Nodulation and Nitrogen Fixing Capacity of Different Rhizobium meliloti

从新疆、重庆和北京3个地区收集了7株苜蓿,从每株苜蓿上分离和纯化出1个根瘤菌菌株。通过抗生素筛选,得到了抗链霉素、新霉素、壮观霉素和卡那霉素的菌株4个,分别是HSmr、ANeor、ⅠSpr和XKmr。4个菌株和7个苜蓿品种做竞争结瘤实验和固氮能力实验结果表明:根瘤菌的竞争结瘤能力是根瘤菌本身的遗传因素和它长期所处的生态环境共进化的结果。几个菌株同时接种时,双感染或多感染普遍发生,并且双感染或多感染发生率受到多种因素的作用,培养条件、苜蓿品种、根瘤菌菌株以及培养条件与苜蓿品种相互作用都影响其发生率。苜蓿的固氮能力受到菌株、苜蓿品种以及两者相互作用的影响。菌株XKmr竞争结瘤能力最差,但固氮能力最强。

Seven individual plants of alfalfa were collected from Xinjiang,Chongqing and Beijing,a rhizobium strain was isolated and purified from each plant.HSm^r,ANeo^r,ⅠSp^r and XKm^r of endurance antibiotic strains were obtained.Seven varieties of alfalfa were obtained from these plants by clonal breeded.Ability of competitive nodulation and fixation nitrogen were studied by hereinbefore describing materials.Result showed that competitiveness of rhizobial strains had been affected by rhizobial genotypes and environment,both infection generally occurred when the same plant was inoculated with a mixture of strains.Their frequency was affected by cultivated conditions,varieties of alfalfa,rhizobial genotypes and reciprocity of cultivated conditions and varieties of alfalfa.Ability of nitrogen fixation was affected rhizobial genotypes,varieties of alfalfa and their reciprocity.XKm^r was the poorest at competitiveness,but it has the strongest ability of nitrogen fixation.