Sel’skokhozyaistvennaya Biologiya [Agricultural Biology], 2011, № 1, p. 54-59 UDK 635.21:581.143.6:57.086.83 FORMATION AND MORPHOMETRIC INDICES OF POTATO MICROTUBERS in vitro AT VARIOUS FORMULA OF SUGARS IN MEDIUM A.N. Deryabin, N.O. Yur’eva K.A. Timiryazev Institute of Plant Physiology, RAS, Moscow 127276, Russia e-mail: anderyabin@mail.ru Received January 13, 2009 S u m m a r y On aseptic culture of potato stolons of the Zhukovskii early and Lugovskoi varieties, isolated in roller in absolute darkness, the authors studied the effect of glucose, sucrose and fructose, supplemented to nutrient medium of Murashige-Skoog (MS-medium), on formation of stolons and tubers. <...> The appearance of only axillary microtubers (40 % — in leaf axil of stem explants and 60 % — in leaf axil of first internode of stolon) the authors observed at the induction of tuber formation by MS-medium with 8 % of sucrose. <...> For the raising of efficiency of tuber formation and the improvement of morphometric indices of microtubers the authors suggest MS-medium with 8 % sucrose, which induces the tuber formation at 7 day of cultivation, replace entirely on analogous in 15-20 days after induction. <...> Conventional modern methods of obtaining potato microtubers (in vitro formed tubers of the diameter less than 10 mm) suggest using test tubes with agar (1) or flasks with liquid (stationary cultivation and/or use of a shaker) medium (2 - 4). <...> All these techniques describe a similar process of growing plants from explants (cuttings with one or more buds) in the light for 4-5 weeks on medium containing 2-3% sucrose with further induction of tuberization (in conditions of darkness or scattered light) by additions of growth regulators and/or raising the sucrose content by 6-9% with further cultivation of microtubers up to their maturation during 5-8 weeks. <...> Tuberization of potato in vitro is known to be determined by a cultivar’s genotype, photoperiod, temperature and composition of nutrient media (9). <...> These processes are subjected to key enzymes of carbohydrate metabolism - invertase and saccharosesynthase: the activity of invertase is very high at the start of tuberization and decreases with maturation of microtubers, while the second enzyme shows a controversial trend of activity (10). <...> The influence of a medium carbohydrate component, its type, form and content inducing tuberization, are being carefully studied for many decades along with duration and rate <...>