Elucidating the role of Kelpak® on the growth, phytohormone composition, and phenolic acids in macronutrient-stressed Ceratotheca triloba.

Masondo N.A., Aremu A.O., Kulkarni M.G., Petřík I., Plačková L., Šubrtová M., Novák O., Grúz J., Doležal K., Strnad M., Finnie J.F., Van Staden J.
JOURNAL OF APPLIED PHYCOLOGY 31: 2687–2697, 2019

Keywords: Abscisic acid, Biostimulant, Cytokinins, Jasmonic acid, Phytochemicals, Traditional leafy vegetable
Abstract: We evaluated the role of Kelpak® on growth, nutritional content, phytohormones, and phenolic acids in the angiosperm Ceratotheca triloba (Bernh.) Hook.f. grown under macronutrient-deficient conditions. Seeds were germinated in the greenhouse and established seedlings were treated with 50% Hoagland’s solution (50% HS) or nutrient-deficient solutions lacking one of the following: nitrogen (-N), phosphorus (-P), potassium (-K), which were either treated with or without Kelpak® (control). After 4 months of growth, macronutrient deficiency severely reduced growth and nutritional composition in plants. Nevertheless, the detrimental effects of insufficient macronutrient supply on growth were ameliorated with the application of Kelpak®, with a fourfold (-N), threefold (-P), and twofold (-K) increase in leaf and root fresh weight. Mineral and carbohydrate levels increased in plants deprived of N and P when Kelpak® was applied in the different soils. Macronutrient stress (N, P, K) increased phytohormone production in C. triloba more than in 50% HS-treated plants. The phytohormone content in macronutrient-deficient leaves was further enhanced with the application of Kelpak®. On the contrary, application of Kelpak® suppressed the production of phenolic acids in 50% HS, -N, and -K-treated plants when compared to the control treatments. The interaction between macronutrient deficiency and Kelpak® application played an important role in the regulation of phytohormone and phenolic acid concentration in C. triloba. The current findings demonstrated the potential of Kelpak® as an efficient biostimulant that enhances nutrient uptake for improved growth and biochemicals in C. triloba under macronutrient stress condition.
DOI: 10.1007/s10811-019-01759-z IEB authors: Karel Doležal, Jiří Grúz, Ondřej Novák, Ivan Petřík, Lenka Plačková, Miroslav Strnad