Abstract
The application of Spirulina platensis aqueous extract (SAE) in foliar spraying has been shown to promote plant growth and yield, as well as to modify the compositions of bioactive chemicals in various plant species. Curcuma longa is an antioxidant-rich medicinal herb that is used as a spice and culinary additive. The application of a natural plant growth enhancer, SAE, to C. longa plants was used in this study to test the effect of SAE for increasing active chemical production. The effects of SAE on the growth, yield and chemical composition of C. longa were investigated. SAE boosted the C. longa growth, yield and curcuminoid content, with SAE at 2 g/L having the most impact. The CURS-1, -2, -3 and DCS genes were found to be differentially elevated by SAE treatments in this investigation. When the plant was sprayed with SAE at 2 g/L, the curcuminoid content (bisdemethoxycurcumin, dimethoxycurcumin and curcumin) increased, which corresponded with the curcuminoid gene's expression level.