Unravelling Synergistic Effects of Palm Bunch Ash and Glutathione on Plant Growth

Palm bunch ash (PBA), a waste biomass from the palm oil industry, has been widely regarded as an alternative source of fertilizer to improve soil health, plant growth and yield. Glutathione (GSH), a bioactive tripeptide with potent antioxidant properties, has been proposed as a plant growth regulator that improves stress tolerance in plants. However, the use of PBA in combination with GSH has yet to be explored and remains as new gap in the literature. Herein, we aimed to assess the individual and the combinatory effects of PBA and GSH on vegetative plant growth, whereby okra was selected as the model plant and cultivated under well-watered, outdoor conditions. Plant growth parameters such as plant height, stem girth, number of leaves and leaf surface area were measured over a period of two months. The results showed that the application of PBA and GSH significantly influenced the plant growth parameters. The GSH-treated group recorded the tallest plant height (47.19 cm) as compared to the control group, PBA-treated group, and combination group of PBA and GSH. The combination group of PBA and GSH recorded the best parameters in terms of stem girth (4.45 mm), number of leaves (6.35), leaf surface area (118.38 cm²) with improved resistance towards diseases. These results implied that the combined application of PBA and GSH may have led to a synergistic effect on okra plant growth. Our findings suggest that the combined application of PBA and GSH is indeed recommended to improve plant growth and development.