Scientific publications

The effect of cytokinin (synthetic 6-benzylaminopurine or BAP) on the fatty acid composition of membrane lipids was studied in curly (Karelian) birch Betula pendular var. carelica (Mercklin) Hamet-Ahti shoots in vitro. The addition of BAP (0.25, 0.5, 1.0, or 2 mg/l concentrations) to the culture medium was found to increase the amount of saturated fatty acids in phospholipids whereas unsaturated fatty acids prevailed in the control. In glycolipids, on the contrary, BAP intensified the synthesis of unsaturated fattacids (mainly, linolenic acid), but the degree of this effect depended on the concentration of the hormone. In the variant with the highest concentration of BAP (2.0 mg/l), for instance, the proportion of linolenic acid decreased. It was hypothesized that the observed modifications in the glycolipid composition are one of the indices of the stimulating effect of cytokinin (up to a certain concentration threshold) on the structure and function of chloroplasts which, due to the photosemixotropy of shoots culture, is an important factor that determines not only their photosynthetic activity but also cell proliferation and direction of in vitro organogenesis.