Seaweed Polysaccharides as A Potential Biostimulant in Turnip Greens Production

Seaweed polysaccharides can substitute synthetic compounds present in commercial stimulants and fertilizers, used in agriculture to improve crops yield and vigor. In this study, three different poly-saccharides (alginate, agar and carrageenan) were extracted from one brown seaweed, Saccorhiza polyschides, and two red seaweeds, Gracilaria gracilis and Chondrus crispus, respectively, and applied on potted turnip greens (Brassica napus L.), with intention to analyze their impact on plant growth, development and metabolism. Turnip plants treated with polysaccharides, specially, carrageenan of Chondrus crispus showed the best results in improving the crop’s productivity, such as plant length and weight, number of leaves, nutrient and pigment content, and soil fertility, compared with turnip plants from the negative control or treated with a commercial leaf fertilizer. λ-carrageenan extracted from the tetrasporophyte generation of Chondrus crispus had the highest bioactivity and positive effect in turnip plants among all treatments. λ-carrageenan has shown that can improve plant growth, increase plant’s biomass, and root system, enhance photosynthetic activity, increase the uptake of soil nutrients, and protect plants against abiotic and biotic stresses, stimulating the production of secondary metabolites and manage its defense pathways. Seaweed extracted polysaccharides have the potential to be used in sustainable agriculture.