Evidence of phytohormones and phenolic acids variability in garden-waste-derived vermicompost leachate, a well-known plant growth stimulant

Aremu A.O., Stirk W.A., Kulkarni M.G., Tarkowská D., Turečkova V., Grúz J., Šubrtová M., Pěnčík A., Novák O., Doležal K., Strnad M., van Staden J.

Keywords: Abscisic acid, Biostimulant, Brassinosteroids, Cytokinins, Gibberellins, Phenolics
Abstract: Cytokinins, auxins, abscisic acid, gibberellins (GAs) and brassinosteroids (BRs) as well as the phenolic acid content in three batches of vermicompost leachate (VCL) were quantified using ultra high performance liquid chromatography–tandem mass spectrometry. N6-isopentenyladenine formed the major (60 %) proportion of the CK content while dihydrozeatin had the lowest (\0.02 %) concentration. Indole-3-acetic acid ranged from approximately 0.55–0.77 pmol/mL. A total of 18 GAs including bioactive forms and metabolic end products were observed in the VCL samples. Cathasterone had the highest (2,500–3,200 fg/mL) concentration while brassinolide was the lowest (1–5 fg/mL) abundant BRs found. Phenolic acids quantified were protocatechuic acid (3–3.6 lg/mL), p-hydroxybenzoic acid (2.5–2.8 lg/mL), p-coumaric acid (1–1.7 lg/mL) and ferulic acid (0–4 lg/mL). These results provide an indication of the rich diversity in natural PGRs and phytochemicals in VCL which may inevitably contribute to the numerous favorable physiological responses elicited by VCL application to plants.
DOI: IEB authors: Jiří Grúz, Ondřej Novák, Miroslav Strnad, Danuše Tarkowská