Effect of glyphosate on morphological, physiological and mitotic parameters of Vigna radiata varieties IPM 02-03 and IPM 02-14

Vigna radiata (L.) Wilczek, a member of Fabaceae, is an important legume cultivated in tropical and subtropical areas of the world. A broad spectrum and non-selective herbicide named glyphosate is widely used to inhibit undesirable weeds and grasses in various landscapes, which can be of agricultural, industrial, urban, forestry and aquatic nature. This can be justified by the fact that its use has increased about 100 times since it was first used in 1970s, making it the world’s most widely used herbicide. The effect of glyphosate on morphological, physiological and mitotic behaviour of two varieties of Vigna radiata IPM 02-03 and IPM 02-14 was evaluated to compare their relative sensitivity to the herbicide. Morphological parameters such as germination percentage, survival percentage, plant height, number of nodes, total number of pods, pod length, number of seeds per pod and number of seeds per plant decreased with increase in dose in both the varieties. Mitotic index was found to decrease with increase in concentration of glyphosate. Number of abnormal cells and relative abnormality rate increased as concentration of glyphosate increased. Oxidative stress has been reported to be induced by herbicides and plants respond to it by upregulation of ROS scavenging enzymes like catalase, peroxidase, superoxide dismutase and glutathione S-transferase. Our results revealed that the activities of CAT, POD, SOD and GST increased with increased concentration of herbicide in both varieties.