Features of the phenolics’ formation in seedlings of different varieties of buckwheat ( Fagopyrum esculentum Moench)

An unique feature of higher plants is the capacity to form phenolic compounds, the substances with high antioxidant activity. These secondary metabolites play an important functional role, including cell and tissue protection against stress factors. It is especially important at the initial stages of plant ontogenesis. Buckwheat ( Fagopyrum esculentum Moench) is the major cereal crop for which the formation of various phenolics, particularly rutin, a biologically active compound of plant origin successfully used in pharmacology, is characteristic. In the young seedlings (at the age of 14 days) of 10 buckwheat varieties mostly bred in Russian research centers during recent decades we studied the morphophysiological parameters and the accumulation of phenolic compounds, including phenylpropanoids and flavonoids, in the hypocotyls and cotyledons. Particularly, the highest level of phenylpropanoids was found in Bol’shevik 4 and Bashkirskaya krasnostebel’naya varieties. Note, it was high and almost equal in the hypocotyls and cotyledons. In the rest varieties the amount of phenylpropanoids in seedlings was 20 to 50 % lower, and in the cotyledons it was 1.5-2.0 times higher compared with the hypocotyls. Accumulation of flavonoids was higher in the Dialog variety, somewhat lower in Bol’shevik 4 and Bashkirskaya krasnostebel’naya varieties (by 10 and 17 %, respectively), and 35 to 40 % lower in the other studied forms. The highest content of anthocyanins was shown in the Bashkirskaya krasnostebel’naya plants, while in other studied buckwheat varieties it was lower. Particularly, in Devyatka, Bol’shevik 4 and Temp plants a decrease was about 50 %, and in Batyr, Dialog, Chatyr tau, Ilishevskaya, Dizain, and Dikul’ varieties 70 to 80 % decrease was found. It was shown that recently bred buckwheat varieties have a very rapid growth and development of seedlings, which is important for their better adaptation in the early ontogeny. The most promising varieties, along with Bashkir krasnostebelnaya, are Bolshevik 4, Nine, Dialogue and Tempo. They are characterized by a high capacity for accumulation the phenolic compounds, the important components of the antioxidant defense system in plants. This feature of their metabolism may be a potential criterion for plant resistance to stress factors