Plants at high altitude exhibit higher component of alternative respiration

Total respiration, capacities of cytochrome (CytR) and alternative respiration (AR) were studied in two varieties of barley (Horedum vulgare) and wheat (Triticum aestivum) each and one variety of pea (Pisum sativum) at low (Palampur; 1300 m) and high attitudes (Kibber; 4200 m). Similar studies were carried out in naturally growing Rumex nepalensis and Trifoilum repenses at Patampur, Palchan (2250 m) and Marhi (3250 m). AR the plants species exhibited tower CytR but significantly higher AR capacity at high attitude (HA) (72-1117% higher) as compared to those at tow attitude (LA). Glycolytic product, pyruvate and tricarboxylic acid cycle intermediate, citrate increased with increase in attitude. While the role of these metabolites in relation to HA biology is discussed, significantly higher AR at HA is proposed to be an adaptive mechanism against the metabolic perturbations wherein it might act to tower reactive oxygen species and also provides metabolic homeostasis to plants under the environment of HA. (c) 2005 Published by Elsevier GmbH.