Triterpene Glycosides as Plant Growth Regulators: Application Potential and Prospects (A Review)

The increased interest in the growth-regulatory activity of triterpene glycosides (TGs) in recent years is largely explained by the need for new highly effective and environmentally friendly plant growth biostimulants, the use of which is considered as an important strategy in managing the productivity and stress resistance of agricultural crops. Тhe review summarizes the available published information on the phytoregulatory activity of TGs with emphasis on their growth-stimulating properties. The physiological effects of TGs in phytohormonal bioassays are considered. The auxin-, gibberellin-, and cytokinin-like effects of TGs on the growth and metabolism of the test plants (changes in the activity of enzymes: α-amylase, peroxidase, catalase, polyphenol oxidase, IAA oxidase, and nitrate reductase, as well as chlorophyll and protein contents) as a function of the structure of the TGs were demonstrated. Some aspects of the mechanism of the growth-stimulating action and the possible involvement of TGs and free triterpenes in physiological processes in plants are discussed. The relationships between the structure and phytoregulatory activity of TGs are analyzed. The effect of exogenous TGs and triterpenoids on plants under abiotic stresses, as well as the possibility to use TGs, extracts of saponin plant sources (Сamellia sp., Silphium perfoliatum, Medicago sativa, Glycine max, Vigna radiata, Glycyrrhiza glabra, Moringa oleifera, Solidago gigantea, Centella asiatica, Eclipta alba, Quillaja saponaria, Bacopa monnieri, et al.) and plant extracts containing triterpenoids (Abies sibirica and Betula sp.) in crop production as plant growth regulators, is considered.