WATER RELATIONS AND NITROGEN-FIXATION IN POTASSIUM FED VIGNA-RADIATA NODULES

Drought created by withholding the irrigation at 30 and 45 d after sow ing significantly decreased relative water content (RWC) and osmotic p otential (psi(s)) of Vigna radiata (L.) Wilczek cv. MH-83-30 nodules. Potassium fed plants showed higher RWC, whereas psi(s), was further de clined irrespective of soil moisture levels. The nitrogenase activity and leghemoglobin content of nodules markedly decreased under drought and nodules of potassium fed plants showed better recovery after rehyd ration. The proline content significantly increased under drought but declined upon reirrigation. Also, the C, N and K contents of nodules s ignificantly declined under drought.