Comparative Study of Agarophytes - Gracilaria edulis and Gelidiella acerosa as Biostimulant and Application of Agar for Water-holding in Soil and Plant Growth Promotion

Abstract

Background: Seaweeds and its derivatives are extensively used as biostimulants in horticulture and agriculture as a replacement for chemical fertilizers. G. edulis and G. acerosa are easily cultivable and economically important seaweeds. They are a rich source of phytohormones, amino acids, antibiotics, vitamins, micro, macro elements and agar. Such natural products have great demand and been commercialized these days to promote sustainable agriculture. Dried and finely powdered algal biomass is used directly as a biostimulant. Algal polysaccharides such as agar can be an innovative alternative to synthetic polymers used in horticulture as they contain active biostimulant compounds and also reported to hold water in the soil that aids plant growth with minimum water consumption than usually required. A. aritis being one of the most consumed leafy vegetables throughout the world can be harvested indoors with added nutrients and minimal water utilization.Methods: The field trial is a comparative evaluation of the two selected species of agarophytes for promoting plant (A. aritis) growth and the extracted agar tested for germination tests, bio-stimulatory property under water stress. Growth parameters were recorded after three weeks. The agarophytes were also qualitatively screened for phytochemicals and WD-XRF analysis.Result: The present work will be a supplementary contribution for assessing agarophytes with biostimulant properties and the characteristic agar gels that expand plant tolerance to abiotic stresses, thus constituting an alternative to synthetic plant protection products.