Journal article

Publication year: 1997

Pages: 83-94

Journal: Journal of the National Science Council of Sri Lanka

Volume number: 25

Issue number: 2

DOI Link: https://doi.org/10.4038/jnsfsr.v25i2.5022

Publisher: Śrī Laṅka Jātika Vidyā Sabhāva

Abstract: 

This study was conducted to investigate the effects of water stress and its relief on growth and N, fmation of common bean (Phaseolus vulgaris L.) and to elucidate the mechanism of regulationof N, fxation by water availability. Plants were grown in N-free nutrient solutions and a water stress of -0.5 MPa was applied 3-weeks after germination by polyethylene glycol. Stress was relieved after 5 days. Water stress reduced leaf water potential and plant relative water content, both of which recovered completely after stress relief. Total plant, shoot and nodule dry weights and the relative growth rate (RGR) of the stressed plants were lower than those of the control during stress. RGR showed a complete recovery after stress relief, but nodule dry weight failed to recover completely. Root dry weight and root:shoot ratio were higher in the stressed treatment both duringstress and a h r i t s relief. Water stress decreased specific nitrogenase activity which recovered partially upon stress relief. There was no correlation between specific nitrogenase activity and total plant soluble sugar concentrations showing that inhibition of specific nitrogenase activity by water stress is not caused by a shortageof assimilate supply to the nodules. Total amino acid concentration increased in shoots and roots, but decreased in nodules in response to stress. This observation suggests that export of reduced nitrogen from nodules was not limited. This is also indicated by the unchanged total nitrogen concentrations in shoots. Based on the evidence of this study, feedback regulation of nitrogenase activity by recyclingof amino acids accumulated in the water-stressed shoots back to the nodules is suggested as a possible mechanism of reduction of nitrogen fxation under water stress.

Harvard Citation style: De Costa, W., Becher, M. and Schubert, S. (1997) Effects of water stress on nitrogen fixation of common bean (Phaseolus vulgaris L.), Journal of the National Science Council of Sri Lanka, 25(2), pp. 83-94. https://doi.org/10.4038/jnsfsr.v25i2.5022

APA Citation style: De Costa, W., Becher, M., & Schubert, S. (1997). Effects of water stress on nitrogen fixation of common bean (Phaseolus vulgaris L.). Journal of the National Science Council of Sri Lanka. 25(2), 83-94. https://doi.org/10.4038/jnsfsr.v25i2.5022