Under favorable conditions in the greenhouse and in the open ground B. grandis subsp. grandis leaves were characterized by relatively low content of the sum of flavonoids (up to 10.1 mg/g). During periods of temperature drops in the greenhouse it was decreased (down to 5.2 mg/g), and in conditions of more considerable temperature drops and frost in open ground it was increased by several times (up to 28.3 mg/g).
During the period of the action of stress factors content of the sum of flavonoid aglycones in the leaves was increased both in the greenhouse (including quercetin, luteolin) and in the open ground (including quercetin, kaempferol, luteolin), in the open ground content of major constituent, luteolin 8-C-glucoside (orientin), was increased. The most significant transformations during the growing season were observed in the O-glycosides and free aglycones fractions, their contents of compounds and composition were varied. Four O-glycosides, including isoquercitrin, are detected only in the leaves of open ground plants. ER -