In: Phyton 61 (2021): S. 109-116; DOI: 10.12905/0380.phyton61-2022-0109; Published online on 15 March 2022

Does biostimulant Agrostemin^® exhibit plant growth regulator activities?

Jana Ambrožic-Dolinšek, Domen Ornik, Rebeka Branda, Zoltán Molnár & Terezija Ciringer
with 3 figures
Key words: Bioassay, Agrostemin, biostimulants, plant growth regulators, auxin, cytokinin.

Summary
Ambrožic-Dolinšek J., Ornik D., Branda R., Molnár Z. & Ciringer T. 2022. Does biostimulant Agrostemin^® exhibit plant growth regulator activities? – Phyton (Horn, Austria) 61: 109–116, with 3 figures.
Agrostemin^® is a natural plant preparation used as a plant biostimulant (PBS) in agriculture. It elicits many positive responses, including yield increases, and is proposed to optimize metabolic processes, growth and development, and stress resistance. The aim of the present study is to identify and quantify whether it exhibits auxin-like and cytokinin-like plant growth regulator (PGR) activities. The ‘Excised Cucumber Cotyledon Root Formation Bioassay’ and the ‘Mung Bean Root Formation Bioassay’ were used to determine the auxin-like activities. The water extract of Agrostemin^® showed auxin-like activity in both bioassays. The activity in the cucumber bioassay was equivalent to about 0.3 mg L^–1 IBA, and in the mung bean bioassay it was equivalent to about 0.5 to 1 mg L^–1 IBA. The ‘Excised Cucumber Cotyledon Expansion Bioassay’ and the ‘Triticum Leaf Chlorophyll Retention Test’ were used to determine the cytokinin-like activities of Agrostemin^®, but both showed no cytokinin-like activity.