The effect of Inoculation and cobalt application on the growth of and nitrogen fixation by sweet lupins

Abstract

The response of sweet lupins, Lupinus angustifolius L., to a soil application of cobalt and to seed inoculation was examined in both field and glasshouse experiments.

Plant growth was dependent on nodule-fixed nitrogen, and the addition of cobalt increased the nitrogen content and the growth of the lupins in the absence of inoculation. Bacteroids in the nodules of inoculated plants without cobalt were found to be fewer and longer than those with cobalt, which suggests that cobalt is involved in the mechanism of rhizobial cell division.