Brown macro-seaweeds derived agro-biostimulant for Zea mays farming in saline conditions: Growth enhancement and optimum biochemical and ion feedback

Salinity negatively affects maize growth, a cereal crop and used as a vital source of food production. Seaweeds are macro-aquatic biocatalysts and might act as a promising biostimulant for conferring crop salinity resistance by providing essential nutrients and growth-promoting regulators. This study was designed for the first time to examine the effects of two commonly found seaweeds, Iyengaria stellata and Colpomenia sinuosa, on the growth of maize under 0, 100, and 200 mM NaCl application. Plants treated with both salinities reduced plant growth, but the application of seaweed I. stellata and C. sinuosa significantly increased growth parameters, especially plant biomass (fresh and dry), length (root and shoot), and total plant height than other treatments. In addition, higher growth under seaweed amends was supported by improved chlorophyll, carbohydrates, carotenoids, and polyphenols as well as lower electrolyte leakages to escape from oxidative stress. Plants treated with both algal species enhanced Na+ and K+, which is important for osmotic balance and precise ion homeostasis and could be effective for optimum leaf metabolism for growth resilience of maize plants under saline-stress conditions. This study emphasizes the potential of C. sinuosa and I. stellata as effective biostimulants. They offer a sustainable approach to cultivating climate-resilient maize that can thrive in salt-affected environments.