Document Type : Articles
Author
Jordan,Aramtha, Alzhohour street Basic Medical Science,Faculty of Nursing.,Irbid National University
Abstract
The application of the herbicide oxadiazon [2-tert-butyl-4-(2,4-dichloro-5-isopropoxyphenyl)-1,3,4-oxadiazol-5-one] to garlic (Allium sativum) resulted in a progressive and concentration-dependent increase in glutathione S-transferase (GST) activity across various plant tissues, including seedlings, roots, shoots, leaves, and stems. GST is a key detoxifying enzyme involved in the conjugation of glutathione to xenobiotic compounds, enhancing their solubility and promoting their removal from cells. In this study, the lowest oxadiazon concentration that induced a statistically significant increase in GST activity was 0.025 ppm (equivalent to 0.025 mg/L), indicating the plant’s sensitivity to even minimal herbicide exposure. The maximal enzyme activity reached more than 275% of control values when plants were treated with oxadiazon concentrations ranging from 10 to 20 ppm. In eight-day-old garlic plants, a notable rise in GST activity was detected in the shoots as early as 6 hours post-exposure, with enzyme levels peaking between 24 and 26 hours, suggesting a time-dependent induction pattern. Other plant species exposed to the same oxadiazon concentration exhibited variable responses. Moderate increases in GST activity were observed in the shoots of broad bean (Vicia faba) and corn (Zea mays), indicating a partial response to herbicide stress. However, no significant changes in GST activity were recorded in lentil (Lens esculenta), bitter vetch (Vicia ervilia), wheat (Triticum aestivum), or barley (Hordeum vulgare), highlighting species-specific differences in herbicide response. These findings emphasize garlic's enhanced capacity for GST-mediated detoxification upon oxadiazon exposure.
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