Exogenous application of triadimefon affects the antioxidant defense system of Withania somnifera Dunal

Triadimefon is a triazole derivative, which have plant growth regulator properties. However, the influential mechanism of triadimefon on medicinal plants like Withania somnifera is not much studied. In the present investigation, the effects triadimefon at 10 mg L-1 on the germination, early seedling growth, photosynthetic pigments, non-enzymatic antioxidant contents and activities of antioxidant enzymes were studied in W somnifera Dunal plants. The germination percentage was not much affected by treatments and early seedling growth was reduced in terms of shoot length and leaf area but root length got increased with a concomitant enhancement in chlorophyll contents. The non-enzymatic antioxidants like ascorbic acid, reduced glutathione and alpha-tocopherol were increased in all parts (root, stem and leaf) of the seedlings. Triadimefon treatment caused an increase in the activities of antioxidant enzymes like superoxide dismutase, peroxidase, polyphenol oxidase and catalase. From our results it can be concluded that, the triadimefon can be used as a potential tool to enhance the antioxidant potential in medicinal plant W somnifera. (C) 2008 Elsevier Inc. All rights reserved.