Regulation of functional activities and essential oil production in Vetiveria zizanioides L. Nash after γ-irradiated sodium alginate elicitation

Abstract

Upon irradiation, marine polysaccharides undergo depolymerization, leading to formation of oligosaccharides that elicit various biological activities in plants. Taking a step further on the previously established growth-promoting activity of irradiated sodium alginate (ISA), structural rearrangements in ISA were analyzed using complementary techniques to develop an understanding of the structure property relationship. The essential oil (EO) of vetiver (Vetiveria zizanioides L. Nash) immensely benefits the perfumery industry, proving itself as an economically important crop. A pot experiment was designed to test the effect of water-soluble ISA fractions on the growth, physiology, and EO production of vetiver. The structural characterization of radiation-induced sodium alginate was carried out using SEM, FT-IR, and UV-Vis spectroscopy. Of the various treatments employed, ISA-120 (ISA applied at 120 mg L 1) proved the best for most of the parameters studied, including fresh and dry weight of plants and photosynthetic attributes. As compared to the control (water-spray treatment), foliar feeding of ISA-120 resulted in an increase of 21.2% in chlorophyll content, while this treatment enhanced the chlorophyll fluorescence by 21.8% at 300 days after transplanting. Application of ISA-120 also increased the EO content by 21.1% and EO yield by 47.6%. Gas chromatography revealed an increase of 30.1% and 92.6% in the values of content and yield of khusimol, respectively, over the control.