AUTHOR=Khan Zawar , Gul Humaira , Rauf Mamoona , Arif Muhammad , Hamayun Muhammad , Ud-Din Aziz , Sajid Zahoor Ahmad , Khilji Sheza Ayaz , Rehman Aliya , Tabassum Asma , Parveen Zahida , Lee In-Jung 

TITLE=Sargassum wightii Aqueous Extract Improved Salt Stress Tolerance in Abelmoschus esculentus by Mediating Metabolic and Ionic Rebalance

JOURNAL=Frontiers in Marine Science

VOLUME=Volume 9 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2022.853272

DOI=10.3389/fmars.2022.853272

ISSN=2296-7745

ABSTRACT=Abstract
Salinity stress has hindered the growth and yield of crops globally. The demands for inducing salt-stress tolerance by natural and biological sources with potent antioxidants and growth-promoting metabolites have been the main focus of the recent era. Therefore, current research is implied to extract the salt-stress tolerance ameliorating metabolites and growth-promoting hormones from marine, brown macroalgae Sargassum wightii Greville ex J. Agardh with maximum antioxidants potential for the use as a liquid fertilizer for okra (Abelmoschus esculentus L.) crop. In the current study, the biochemical analysis showed that Sargassum aqueous extract (SAE) was rich in growth-promoting metabolites, antioxidants, and hormones. While over-accumulation of glycine betaine attracted the focus of current research dealing with salt-stress tolerance amelioration in okra. The plants supplemented with SAE (2% and 4%) and ascorbic acid (0.04%) alone and in combinations, were subjected to sodium salt-stress (NaCl 75 mM). Results revealed that SAE efficiently promoted the vegetative and reproductive growth of plants by elevating the growth-promoting metabolites and hormones in comparison to control plants. Ionic contents (Na+, K+, Ca2+and Mg2+), and ratios (K+/Na+, Mg2+/Na+, and Ca2+/Na+) were modulated in SAE treated plants. SAE also increased the level of carbohydrates, proteins, lipids, carotenoids, proline and decreased the level of hydrogen peroxide and abscisic acid in salt-treated plants compared to control groups. Enzymatic activities of catalase, ascorbate peroxidase, and guaiacol peroxidase were also enhanced by SAE treatment upon salt stress. SAE-mediated stress tolerance ameliorating and positive growth response of okra was further accelerated by AsA (0.04%) supplementation used in combination with SAE (2% and 4%). The current study revealed a novel report of antioxidant and metabolites-rich algal extract (Sargassum weightii) formulation along with AsA that induced salts stress tolerance and promoted the overall growth performance of okra by rebalancing the ionic and metabolic status.