Insights into the role of cytokinin and gibberellic acid in improving waterlogging tolerance of mung bean

Abstract Mung bean (Vigna radiata) is one of the most important pulse crops, well-known for its protein rich seeds, which growth and productivity are severely undermined by waterlogging. In this study, we aim to evaluate how two promising phytohormones, namely cytokinin (CK) and gibberellic acid (GA3), can improve waterlogging tolerance in mung bean by investigating key morphological, physiological, biochemical and yield-related attributes. Our results showed that foliar application of CK and GA3 under 5-days of waterlogged conditions improved mung bean growth and biomass, which was associated to increased levels of photosynthetic rate and pigments. Waterlogged-induced accumulation of reactive oxygen species, and the consequent elevated levels of malondialdehyde, were considerably reduced by CK and GA3 treatments. Mung bean plants sprayed with either CK or GA3 suffered less oxidative stress due to the enhancement of total phenolics and flavonoids levels. Improvement in the contents of proline and total soluble sugars indicating a better osmotic adjustment following CK and GA3 treatments in waterlogged-exposed plants. Most fundamentally, CK or GA3-sprayed waterlogged-stressed mung bean plants demonstrated an increased tendency of the above-mentioned parameters after the 15-day recovery period as compared to water-sprayed waterlogged-exposed plants. Our results also revealed that CK and GA3 treatments increased yield-associated features in waterlogged-stressed plant. Importantly, both phytohormones are efficient in improving mung bean resistance to waterlogging; however, CK was found to be more effective. Overall, our findings suggested that CK or GA3 could be used for the management of waterlogging-induced damage in mung bean, and perhaps in other cash crops.