Chlorophyll a Fluorescence as an Index Characterizing the Physiological State of Taraxacum officinale Wigg. under Conditions of Mountainous Dagestan

The results of a study of the photosynthetic efficiency, as well as the qualitative and quantitative composition of free amino acids in dandelion (Taraxacum officinale Wigg.) plants growing in Republic of Dagestan at various altitudes are presented. These complex studies show the high adaptability of dandelions to abiotic stress factors. As the altitude zoning increases, the efficiency of the solar energy transformation (Y(II)) in plants decreases due to photoinhibition (β and Ib). An increase in the relative rate of a noncyclic electron flow in the electron transport chain allows highland plants to maintain photosynthesis at the required level, thus providing the required energy balance and bioproductivity. Sixteen free amino acids have been identified in roots of T. officinale, including six essential amino acids that possess antioxidant properties. The amount of free amino acids varies depending on the zonality: the contents of α-alanine, arginine, methionine, serine, cysteine, threonine, and proline are higher in highland specimens. Altitude-associated changes in biophysical reactions and primary metabolites of the studied plants result from the impacts of abiotic factors and have an adaptive character.