Effects of prolonged drought stress and nitrogen deficiency on the respiratory O2 uptake of bean and pepper leaves
1997
Gonzales-Meler, M.A. (Duke Univ., Durham (USA). Botany Dept.) | Matamala, R. | Penuelas, J.
We analyzed the combined effects of mild drought stress and severe nitrogen (N) deprivation on respiration of acclimated mature leaves of beans (Phaseolus vulgaris) and peppers (Capsicum annuum). Rates of oxygen uptake were measured polarographically, and inhibitors were added to the closed cuvette to compare the effects of environmental stress on the cytochrome (cyt) and alternative pathways of mitochondrial respiration. Dark oxygen uptake was decreased by the water deficit treatment in both plants, and in the case of N limitation leaf respiration rates (Rd) of peppers were also reduced. RD of leaves of beans and peppers grown under N-limiting conditions did not follow the decrease in leaf N concentration, since RD was considerably higher in the N-stressed leaves. Values obtained with specific inhibitors of the two terminal oxidases of mitochondrial respirations suggested that the cyt pathway of respiration was affected by mild drought and severe N stress. When plants were exposed to both environmental stess, leaf respiration response was similar to that under N limitation, in this case the most severe stress.
显示更多 [+] 显示较少 [-]