Dynamics of aminoacids content in Betula pubescens and B. pendula (Betulaceae) buds and leaves during vegetative period
2007
Shulyakovskaya, T.A. | Vetchinninikova, L.V. | Repin, A.V. | Shreders, S.M., Russian Academy of Sciences, Petrozavodsk (Russian Federation). Karelian Research Centre
Free and protein amino acids composition and content in Betula pubescens Ehrh., B. pendula Roth and B. pendula var. carelica (Mercklin) Hamet-Ahti buds and leaves in spring-summer-autumn season have been studied. The amino acid composition in birch buds and leaves was found to change during their vegetative development, this being especially conspicuous in the free amino acid pool. Throughout the study period, the prevalent protein amino acids were lysine, as well as glutamic and aspartic acids, leucine and arginine. Free amino acids have a more variable composition than protein ones. Thus, aspartic acid prevails in swelling and breaking buds in spring. As leaves form, the glutamic acid content grows considerably in addition to the aspartic acid, reaching the maximum during the leaf yellowing phase, when the proportion of the aspartic acid there decreases significantly. By autumn, the newly formed buds accumulate arginine, which content is maximal during dormancy. It was demonstrated that changes in the composition of free i amino acids in birch buds and leaves are related primarily to shifts of development phases irrespective of the species.
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