Effects of abscisic acid and methyl jasmonate on the recovery of hail damaged rose geranium (Pelargonium graveolens) plants

The goal of this investigation was to study changes of the levels of phenolic acids and flavonoids in leaves of Lavandula angustifolia Mill., L. latifolia Medic. and their amphidiploid L. × intermedia Emeric ex Loisel. The levels of phenolics were determined by UV-Vis spectrophotometry. Phenolic acids and flavonoids were identified and quantified by the HPLC-DAD method. The levels of total phenolics in L. latifolia leaves (29.3-90.2 mg g^‑1d.w.) were found to be higher than those in L. angustifolia (27.2-56.3 mg g^‑1 d.w.) and the amphidiploid L × intermedia (27.7-66.1 mg g^‑1 d.w.). The maximal levels of total phenolics were found during the period of massive flowering. Three phenolic acids were quantified in lavender leaves: neochlorogenic, trans-caffeic, and rosmarinic acids. The extracts also contained apigenin-7-O-glucoside, luteolin-7-O-glucoside and coumarin. The maximal levels of rosmarinic acid (4.6 mg g^‑1 d.w.) and luteolin-7-O-glucoside (0.1 mg g^‑1 d.w.) were found in L. latifolia leaves at the end of the growing season. The maximal levels of neochlorogenic acid (0.3 mg g^‑1 d.w.) and apigenin-7-O-glucoside (1.7 mg g^‑1 d.w.) were found in leaves of L. angustifolia at the beginning of the growing season. Trans-caffeic acid was not found in L. angustifolia. Its content in L. latifolia leaves reached its maximum (0.7 mg g^‑1 d.m.) at the end of the growing season. Apigenin-7-O-glucoside was not found in amphidiploid leaves, and trans-caffeic acid appeared in trace amounts only at the beginning and at the end of the vegetation period. Thus, the levels of the total phenolics and individual components in the amphidiploid L. × intermedia occupy an intermediate position between those in the original parental forms. Our data demonstrate that leaves of L. angustifolia, L. latifolia and their hybrids can be a valuable source of phenolic antioxidants. This study was supported by the research grant No. 14-50-00079 from the Russian Science Foundation.