Changes in antioxidant activities of Vigna radiata (L)Wilczek

Abida Aziz, Dr. Syed Hammad Raza and Dr. Mumtaza Hussain

Department of Botany, University of Agriculture, Faisalabad, Pakistan

E-mail:amber_botanist@ymail.com

Abstract

Zinc is an essential micronutrient but at higher concentration it causes oxidative stress.  A study was conducted to investigate the enzymatic detoxification of high concentration of reactive oxygen species (ROS) in shoot of Vigna radiata. Seeds were grown in Hoagland growth medium with five treats of Zinc sulphate (control, 2.5.5,7.5, and 10 mmol). Statistical design for experiment was laid out in CRD manners in stress physiology lab, Department of Botany University of Agriculture, Faisalabad. Seedling growth was enhanced at 2.5 mmol concentration of Zinc but significant reduction in growth was observed at 7.5 and 10 mmol treatment level. Antioxidant enzyme system greatly influenced by different level of Zinc toxicity. Activity of catalase (CAT) and superoxide dismutase (SOD) was significantly decreased in seedlings, however at 5 mmol of Zinc concentration, their activity was increased. Peroxidase (POD) activity was enhanced in all level of Zinc treatments. From the present investigation, it is concluded that Zinc toxicity affect the activity of antioxidant enzyme which are the first line of defense for reactive oxygen species (ROS). Antioxidant enzyme like SOD, CAT and POD are found to be susceptible to Zinc resulting in a decline in their catalytic activities. This decline in antioxidant efficiency is an important factor in generating oxidative stress in plants under Zinc toxicity.

Key words: Zn toxicity, Antioxidant, Leguminous plants, Enzymatic

 detoxification, Reactive oxygen species.

Present Address: C/O. Dr. Mumtaza Hussain, Professor of Botany, Department

of Botany, University of Agriculture, Faisalabad, Pakistan 92-41-9200161-69 Ext. 3307.