Hydrogen sulphide and nitric oxide mitigate the negative impacts of waterlogging stress on wheat (<i>Triticum aestivum</i> L.)
Manar Fawzi Bani Mfarrej, Xiukang Wang, Muhammad Hamzah Saleem, Iqbal Hussain, Rizwan Rasheed, Muhammad Arslan Ashraf, Muhammad Iqbal, Muhammad Sohaib Chattha, Mohammed Nasser Alyemeni
Abstract
Abstract Nitric oxide (NO) and hydrogen sulphide (H 2 S) are important gaseous signalling molecules that regulate key physiochemical mechanisms of plants under environmental stresses. A number of attempts have been made to improve waterlogging tolerance in plants, but with limited success. Having said that, NO and H 2 S are vital signalling molecules, but their role in mitigating waterlogging effects on crop plants is not well established. We investigated the efficacy of exogenous NO and H 2 S to alleviate waterlogging effects in two wheat cultivars (Galaxy‐2013 and FSD‐2008). Waterlogging produced a noticeable reduction in plant growth, yield, chlorophyll, soluble sugars and free amino acids. Besides, waterlogging induced severe oxidative damage seen as higher cellular TBARS and H 2 O 2 content. Antioxidant enzyme activity increased together with a notable rise in Fe 2+ and Mn 2+ content. Proline content was higher in waterlogged plants compared with non‐waterlogged plants. In contrast, waterlogging caused a substantial decline in endogenous levels of essential nutrients (K + , Ca 2+ and Mg 2+ ). Waterlogged conditions led to Fe 2+ and Mn 2+ toxicity due to rapid reduction of Fe 3+ and Mn 3+ in the soil. Exogenous NO and H 2 S significantly protected plants from waterlogging effects by enhancing the oxidative defence and regulating nutritional status. Besides, the protective effects of exogenous NO were more prominent as compared with effects of H 2 S. Further, we did not study the effect of H 2 S and NO on photosynthetic attributes and expression of stress‐related genes. Therefore, future studies should examine the effects of H 2 S and NO on wheat physiology and gene expression under waterlogging.