Seaweed-Derived Biostimulant (Kelpak®) Influences Endogenous Cytokinins and Bioactive Compounds in Hydroponically Grown Eucomis autumnalis

Abstract

The effect of a seaweed-derived biostimulant (Kelpak® at 1, 2.5 and 5 % dilution; v/v) on the growth, endogenous cytokinin (CK) and phytochemical content in Eucomis autumnalis (Mill.) Chitt. under hydroponic conditions was evaluated. After 4 months, the stimulatory effect of Kelpak® treatments was more noticeable in the underground organs than in the aerial organs. Total endogenous CK was also higher in plants treated with Kelpak® (c.a. 1000–1200 pmol g−1 DW) compared to control plants (860 pmol g−1 DW). Isoprenoid CKs (which mainly accumulated in the aerial organs) were more dominant than aromatic-type CKs across all the treatments. A total of 11 bioactive chemicals (8 phenolic acids and 3 flavonoids) and eucomic acid known for their diverse biological activities were quantified in the samples. The most abundant compound was p-coumaric acid (6.5 µg g−1 DW) and it was approximately sevenfold higher in 2.5 % Kelpak®-treated plants than in the control. It was also noteworthy that syringic acid only occurred in the underground organs of 5 % Kelpak®-treated plants. Eucomic acid which is a major bioactive compound in E. autumnalis was significantly enhanced in Kelpak® treatments, and the leaves accounted for more than 70 % of the overall content. Thus, Kelpak® elicited a significant influence on the growth, endogenous CK and phytochemical content in E. autumnalis. These findings provide additional evidence of the enormous potential of Kelpak® as a useful biostimulant with practical applications in various agricultural endeavours.