Ecology, Environment and Conservation Paper

DIFFERENTIAL CARBON MONOXIDE SENSITIVITY OF CYTOCHROME OXIDASE IN HIGH AND LOW NITROGEN USE EFFICIENT WHEAT (TRITICUM AESTIVUM L.) GENOTYPES

B.B. Abuj, U.S. Dalvi, P.K Lokhande, V.P. Chimote and R.M. Naik

Abstract

A small increase in cytosolic NADH can influence the nitrate reduction and thus appears to be critical for improving nitrogen use efficiency. The differential carbon monoxide (CO) sensitivity of high and low nitrogen use efficient wheat genotypes and relatively higher induction of CO response in low nitrogen use efficient wheat genotypes by prior infiltration with 2,4 dintro phenol before CO exposure suggest differences in redox state of cytochrome oxidase during in situ respiration. The process of oxidative phosphorylation appears to tightly coupled in mitochondria of nitrogen use inefficient wheat genotypes due to low NADH/ NAD+ ratio as evident from oxidized state of cytochrome oxidase which does not form complex with CO, whereas in high nitrogen use efficient wheat genotypes the non-energy conserving alternative dehydrogenases appears to be more active due high matrix reduction level with cytochrome oxidase in the more reduced form.