Partitioning and Utilization of Carbon and Nitrogen in Nodulated Roots and Nodules of Chickpea (Cicer arietinum) Grown at Two Moisture Levels

Abstract

The partitioning and utilization of carbon (C) and nitrogen (N) in nodulated roots and nodules of chickpea (Cicer arietinum L.) was studied at two moisture levels at 10-d intervals 40-140 d after sowing (DAS). More C was used in respiration and less in growth of nodulated roots and nodules under water stress compared to controls during all growth stages except at the early vegetative stage. Similarly, less nitrogen was invested in dry matter of both nodules and nodulated roots under stress, except during the vegetative stage where more nitrogen was used. Calculated over the entire growth period, as much as 14 and 20% of the total nitrogen and 3 and 4% of the total carbon fixed by the plant was lost to the rooting medium under controlled and stressed conditions, respectively. The efficiency of nitrogen fixation with respect to net C utilization was maximal during seed filling under both control and stress conditions However, the efficiency of nitrogen fixation was always greater under drier conditions.