Toxicological aspects of pendimethalin induced activities of certain oxidising and hydrolytic enzymes in the germinating seedlings of maize (Zea mays L.)

Abstract

Maize (Zea mays L.) variety NAC-6002 grains were exposed to a range of field relevant concentrations (0.5, 1.0, 2.5, 5.0 and 10.0 ppm) of formulated grade of pendimethalin. The seedlings were maintained in Hogaland and Arnon's nutrient media for up to 15 days to study the toxicity of pendimethalin on germination and activities of certain oxidizing and hydrolytic enzymes using embryonic axis and endosperms of 4, 6, 8, 10 and 15-day-old germinating maize seedlings. The percent germination, length of radicle and plumule decreased significantly with increasing pendimethalin concentrations. The α-amylase activity in the treated seedlings decreased with increasing concentration of pendimethalin in both endosperm and embryonic axis of maize seedling, when compared with control in all the days of observations. The catalase, peroxidase and polyphenoloxidase activity was high in both cotyledons and embryonic axis of treated sets at all time intervals of seedling during early growth over the period of 15 day when compared to control. However, catalase and peroxidase activity was decreased and polyphenoloxidase activity was higher in treated seedlings at higher pendimethalin concentrations. The present study therefore indicates that herbicidical stress brings constraints in the physiological events of seed germination and enzyme activity.