Sevil B. Dadashova
Low temperatures alter the structural and functional properties of chloroplast membranes and negatively affect photosynthetic activity.In the present study, Triticum aestivum seedlings were incubated at 4˚C to evaluate the protective effects of triterpene saponins isolated from Glycyrrhiza glabra roots and steroidal saponins isolated from Yucca aloifolia roots, which differ in their chemical structure.The DPPH assay demonstrated free radical scavenging activity of triterpene saponins (IC 50 = 1.26 µg/ml) and steroid saponins (IC 50 = 7.3 µg/ml).Analysis of fluorescence and absorption spectral characteristics showed that the studied saponins contributed to the restoration of photosystem II activity under low-temperature stress, including partial recovery of electron transport processes at the P680 + -Q A -Q B site and stabilization of chlorophyll a 680 and chlorophyll b 645 absorption in the chloroplast antenna complex.In addition, treatment with saponins was associated with a reduction in PNRSV viral load in Gizella 6 cherry rootstock, as determined by ELISA.The obtained results suggest that triterpene and steroidal saponins may contribute to the maintenance of photosynthetic membrane functions under cold stress conditions through their antiradical and membranotropic properties.