Symbiosis, Nitrogen and Dry Matter Distribution in Chickpea (Cicer arietinum)

Abstract

SUMMARYIn symbiotically-dependent chickpea, nodule mass and rates of nitrogenase activity increased when vegetative growth increased rapidly, but declined during fruiting. The specific activity of nodules declined as their mass rapidly increased. Nodule mass and rates of nitrogenase activity varied between genotypes, as did the point of maximum activity, which in some genotypes occurred before fruit growth dominated shoot growth. Current N2-fixation supplied most of the nitrogen for pod and seed growth, but in some genotypes mobilization of nitrogen from vegetative parts was evident. Seed attracted up to 50% of assimilated nitrogen; residual nitrogen was contained mainly in leaf and pod tissue, though in one genotype stem nitrogen was plentiful.