云南七彩花生根瘤菌固氮能力及其与豆血红蛋白含量的关系

Nitrogen Fixation Capabilities of Rhizobia in Yunnan Colorful Peanut and Their Associations with Leghemoglobin Concentration

为了阐明豆血红蛋白在花生与根瘤菌互作关系中的作用,通过对云南省元谋干热河谷区七彩花生根瘤中分离到的29株慢生根瘤菌进行盆栽接种试验,研究了各菌株对云南七彩花生生物量和植株全氮与豆血红蛋白含量的影响,探讨了植物生物量、根瘤菌固氮能力与豆血红蛋白总量和根瘤鲜质量的关系。结果表明:与对照组相比,接种各根瘤菌菌株后植株生物量、株高均明显提高,总体上不同根瘤菌之间的固氮能力差异不显著,其中来自七彩花生种植地的根瘤菌固氮效果高于其他来源的根瘤菌。豆血红蛋白总量、根瘤鲜质量均与花生生物量和植株氮总量呈极显著正相关,但豆血红蛋白总量的解释力更高。去除根瘤质量的影响后,花生生物量、植株氮总量与豆血红蛋白含量仍具有极高的相关性,表明豆血红蛋白是影响花生根瘤固氮能力的关键因素,可以作为筛选高效固氮根瘤菌菌株的重要指标。此外,本研究表明,作为云南省的乡土品种,七彩花生可以通过豆血红蛋白的增减来调节对不同固氮能力根瘤菌的资源投入,实现其与根瘤菌共生关系间的奖惩机制。

To clarify the role of leghemoglobin in the interaction between peanut and rhizobium,29 strains of Bradyrhizobium were isolated from colorful peanut nodules in the dry-hot valley of Yuanmou,Yunnan Province.By an inoculation experiment,the effect of each strain on the plant biomass,total nitrogen,and leghemoglobin content of colorful peanut were studied.The correlation of plant biomass and ability of nitrogen fixation with total leghemoglobin and fresh nodule mass was investigated.The results showed that the plant biomass and plant height were significantly increased after inoculation of rhizobial strains compared to the control group.Generally,there were no significant differences in nitrogen fixation ability among different rhizobial strains.The rhizobial strains isolated from the planting field of colorful peanut had better capabilities of nitrogen fixation than those isolated from other sources.Both total leghemoglobin and fresh nodule mass were positively correlated with peanut biomass and plant total nitrogen content.However total leghemoglobin could explain more variations in peanut biomass and plant total nitrogen content than fresh nodule mass.After removing the effects of nodule mass,peanut biomass and plant total nitrogen content were still highly correlated with leghemoglobin concentration,indicating that leghemoglobin was a key factor affecting the nitrogen fixation capabilities of peanut nodules and could be used as an important index for screening efficient nitrogen-fixing rhizobial strains.Furthermore,this study showed that as a native variety in Yunnan,colorful peanut could control the allocation of the resource to rhizobia with different nitrogen-fixing capabilities through the changes of leghemoglobin,thereby implementing the sanction mechanism in the symbiotic relationship with rhizobia.