Diverse antioxidative effects in Pui vegetable (Basella alba) induced by high temperature stress

Basella alba is a green vegetable and grows in both winter and summer; however the temperature sensitivity on metabolic regulation in this species is not clarified. To identify the physiological mechanisms involved in regulation of adaptive response and anti oxidative effects in leaves of Basella alba, plants grown in pot were exposed to high temperature (45 oC) for 24h, 48h and 72h periods and polyphenol oxidase (PPO) and peroxidase(POD) activities in leaves were examined. High temperature causes the higher activity of PPO and the activity was found to be potential after prolonged exposure when compared to the respective controls. Dose response characteristics of substrate on PPO activity were performed. The activity was higher at 10 mM catechol, substrate for the enzyme, than 100 mM and 200 mM concentration, however, the three doses yielded the gradual increase in activity. Conversely, POD activity in leaf was regulated reciprocally and found to be prevented up to 72h of treatment however the effects were appeared to be pronounced after 48h of exposure. The above findings demonstrate that assay of PPO and POD in response to high temperature is an index for characterization of anti oxidative effects in this species of plant and will give a new insight for adaptive response to the adverse environment.