Total amylase activity of in vitro germinated Cyperus esculentus (L.) tubers treated with salt and heavy metals

The growth of seeds and tubers is a major concern due to increased salt stress and widespread accumulation of heavy metals in agricultural land. Amylase is an important enzyme involved in germination processes and seedling development. This study was carried out to determine the effects of salt stress and heavy metals on the activity of amylase in in vitro germinated Cyperus esculentus. Sodium chloride (NaCl), at concentrations of 0, 50, 100, 150, 200, 250 and 300 mM, were used to evaluate the effect of salt stress. Four heavy metals, cadmium, zinc, lead and arsenic, at concentrations of 0, 50, 100, 150, 200, 250 and 300 ppm were used to determine the effect of heavy metals, on the total amylase activity of in vitro germinated Cyperus esculentus (L.) (tiger nut). Total amylase activity was determined eight days after treatment (8DAT). The results obtained showed that NaCl marginally increased total amylase activity. The mean values obtained for total amylase under 0, 50 and 250 mM NaCl treatments were 118.967±1.073, 118.540±0.523, and 120.127±0.318 µM glucose released/min/g FW respectively. For 0, 250 and 300 ppm arsenic ion (As) solutions mean values for total amylase activity were 38.77±0.54, 39.21±0.95 and 30.07±0.41 µM glucose released/min/g FW. Cadmium (Cd) solutions increased total amylase activity as the concentration increase. Lead (Pb) solutions did not show any profound differences in the enzyme activity. Total amylase activity in 0, 200 and 300 ppm Pb solutions were 38.77±0.54, 38.89±0.65 and 38.47±0.61 µM glucose released/min/g FW. It was observed that total amylase activity under As and Zn solutions were similarly patterned.