Kinetics of metabolism in sugarcane (Saccharum officinarum L.) under heat stress

A study was conducted to determine the kinetics of metabolism of sugarcane in vivo under heat stress. 30-days-old sugarcane settlings (Co 86032) were subjected to critical temperature (40 °C) for 5, 10, 15, 20, 25 and 30 h. The metabolic changes in terms of total phenolics, total sugars, proline, glycinebetaine and reactive oxygen species (ROS) scavenging enzymes activity and isozyme pattern were studied at different temperatures. A linear accumulation of soluble sugars, free proline and glycinebetaine (up to 25 h of heat stress treatment) was evident in sugarcane sprouts due to heat stress, although none of these metabolites accumulated under control conditions suggesting their role in osmotic adjustment and thereby in protecting cells from heat damage for short heat stress conditions. Heat stress induced increase in total phenolics content of settlings (44.5-128.5 μg g-1 FW) and callus (37.5-105.1 μg g-1 FW) with the gradual increase of sampling timing (5-25 h) might play a role in the prevention of stress-induced oxidative damage and maintenance of osmotic balance. High temperature stress enhanced the activity of antioxidant enzymes up to 15 h of 40 °C temperature stress and after wards declined. Higher degree of expression of peroxidase and superoxide dismutase isoform and their activities lead to protection of cells from oxidative damage under heat stress suggesting that the plants have developed enzymatic control of scavenge ROS under short term stress. © 2013 Indian Society for Plant Physiology.