Impact of seaweed extract on plant growth, yield and stress tolerance

Abstract

Seaweed extracts have emerged as effective natural bio-stimulants in sustainable agriculture due to their eco-friendly nature and rich composition of bioactive compounds. With the increasing demand for food production and the adverse environmental impacts associated with excessive chemical fertilizer use, seaweed-based formulations offer a viable alternative. According to Hong, Hien and Son (2007), seaweeds serve as an important source of bioactive compounds that enhance plant growth while minimizing ecological damage. Seaweed extracts, particularly derived from brown, red, and green macroalgae, contain essential nutrients, vitamins, polysaccharides, and natural plant growth regulators such as auxins, cytokinins, gibberellins, and abscisic acid (Khan et al., 2009; Mukherjee and Patel, 2020). Research by Blunden and Wildgoose (1977) demonstrated that seaweed extracts significantly enhance root and shoot growth and increase chlorophyll content, while Crouch and van Staden (1993) reported improvements in flowering, fruit set, and overall crop yield. Enhanced nutrient uptake of nitrogen, phosphorus, and potassium following seaweed application has been documented by Khan et al., (2009). Furthermore, seaweed extracts play a crucial role in improving plant tolerance to abiotic stresses such as drought, salinity, and temperature extremes. Zhang and Ervin (2004) showed that cytokinin-rich seaweed extracts alleviate drought-induced stress by maintaining osmotic balance and reducing oxidative damage, while Craigie (2011) reported reduced salinity stress through improved physiological regulation. Seaweed extracts also contribute to soil health by stimulating microbial population and metabolic activity, as observed by Alam et al., (2013), leading to better root development and nutrient absorption. Yield enhancement in treated crops is strongly associated with hormonal activity, particularly cytokinins, as reported by Abetz and Young (1983) and Van et al., (1984). Overall, seaweed extracts function as multifunctional bio-stimulants that enhance plant growth, yield, stress tolerance, and soil fertility, making them an integral component of organic and sustainable agricultural systems.