磷水平和接根瘤菌对紫花苜蓿根系形态特征和根瘤固氮特性的影响

以‘甘农3号’紫花苜蓿(Medicago sativa ‘Gannong No.3’)为材料,采用营养液沙培法,研究了磷及根瘤菌对紫花苜蓿根系形态和根瘤固氮酶活性的影响,结果表明:接种根瘤菌或在一定范围内(0~2000 μmol·L^-1)提高磷水平,均可显著增加紫花苜蓿的根长、根表面积、根平均直径、根体积和根系活力,并使其根瘤数增多,根瘤重增大,固氮酶活性显著增强,植株全氮含量增加;与不接菌相比,接菌提高了紫花苜蓿对磷的需求;本试验条件下紫花苜蓿所需磷素最佳范围为1000~1500 μmol·L^-1。

Effects of Phosphate Levels and Rhizobium Inoculation on the Root Morphology and Nitrogen-fixing Characteristic of Alfalfa

The effects of phosphate levels and rhizobium on the root morphology and nitrogen-fixing characteristic of Medicago sativa ‘Gannong No.3’ were studied by sand culture method. The results showed that rhizobium inoculation and appropriately improving the phosphorus levels (0~2000 μmol·L^-1) could markedly increase alfalfa root length, root surface area, average root diameter, root volume, root nodule number and root nodule weight, as well as root activities, nitrogenase activity and total nitrogen content; Rhizobium inoculation increased the demands of alfalfa for phosphate; The optimal phosphorus level of alfalfa is from 1000 μmol·L^-1 to 1500 μmol·L^-1.