接种根瘤菌对西南地区大豆光合性能和固氮能力的影响

为探讨接种根瘤菌对西南地区大豆固氮能力的有效性，在大田试验条件下，以根瘤菌株 Bradyrhizobium japonicum5038和B. japonicum 5136侵染南黑豆20和南夏豆25，比较两个大豆品种接种后植株的光合特性和叶绿素 含量，考察根瘤数量并测定分析其蔗糖含量、豆血红蛋白含量和固氮酶活性。结果表明：接种后两大豆品种叶片 chla/b值显著下降，叶绿素含量、净光合速率和气孔导度显著增加；根瘤数、单株瘤重、植株地上部和地下部生物量 均显著增加，单个瘤重和根冠比则无显著变化；根瘤内蔗糖含量和豆血红蛋白含量均显著增加，固氮酶活性提高。 不同大豆品种对不同菌株的响应不同，南夏豆25与根瘤菌B.japonicum5136的适配性最好，接种后大豆光合性能和 固氮能力的改善效果明显优于南黑豆20。

Effects of inoculation of different rhizobium on photosynthetic characteristics and nitrogen fixation of soybean

To investigate the soybean nitrogen fixation ability response to the inoculation of different rhizobi um,two soybean varieties,Nandou 20(ND20)and Nanxiadou 25(ND25),were inoculated with Bradyrhizobium ja ponicum 5038 and B.japonicum 5136 in this field experiment.The photosynthetic traits,chlorophyll content,nodule number and the physiological index of fresh nodule,such as sucrose content,leghaemoglobin content and nitroge nase reductive ability were investigated.The result revealed that chlorophyll content(chl),photosynthetic rate(Pn)and stomatal conductance(Gs)increased significantly but chla/b value decreased significantly after inoculation.Nodule number,nodule biomass,shoot and root biomass all increased significantly,biomass per nodule and root/shoot value changed without significace.Sucrose content,leghemoglobin content and nitrogenase reductive ability of nodule all increased significantly.Compared with ND20,ND25 had bigger increasing amplitude,not only the photo synthetic characteristics but also the nodule characteristics and nitrogenase reductive ability.