Partitioning of14C assimilates, total14C activity and growth under water stress and during recovery in indeterminateCajanus cajanL.

Distribution of14C, in different plants parts of pigeonpea (Cajanus cajanL.) was assayed by moving14CO2-fed plants to moderate (Soil ψw = −0•77 MPa) and severe (soil ψw = −1•37 MPa) levels of water stress. In shoots at the vegetative stage, the ethanol soluble fraction represented 98•7% of total14C content at zero time, which decreased to 48•5% after 120 h. In underground portions it increased from 1•3% to 51•5%. A similar trend was observed for the ethanol insoluble fraction. Nodules showed the highest percent of14C content under drought. At the flowering stage a similar trend was observed for14C distribution, however, in reproductive parts14C amount increased six times in the soluble fraction and two times in the insoluble fraction after 168 h. Under severe stress 27•1% and 27•0% of total14C content was diverted to reproductive parts and nodules, respectively. In plants revived after stress14C was reduced to 50% in retained reproductive parts. High rates of respiration of nodules and leaves were noted even at low rates of photosynthesis under moderate stress. Total14C activity decreased with time to 32•2% and 13•5% at moderate stress during the vegetative and flowering growth stages, respectively. Recovered plants showed higher14C activity than the control