SUCROSE AFFECTS THE PHOTOSYNTHETIC APPARATUS AND THE ACCLIMATION OF TRANSGENIC TOBACCO TO EX-VITRO CULTURE

Nicotiana tabacum L. cv. Samsun (control) and two clones of transgenic tobacco plants with introduced Agrobacterium tumefaciens single ipt-g ene, were grown in vitro on agar with or without 2 % of sucrose. Trans fer to ex vitro culture resulted in a general improvement of photosynt hetic characteristics (e.g., elevated chlorophyll content, continuousl y rising photochemical efficiency of photosystem 2). After transfer to soil the improvement of photosynthetic characteristics was larger in plants grown without sucrose in the agar medium than in those grown wi th sucrose. Significant differences between both types of in vitro cul tivation were observed in the polypeptide profiles of thylakoid membra nes where a stable assembly of photosystem 1 (PS1) complex (approximat e to 110 kDa) was missing in plants originally grown without sucrose. Differences were apparent till the 10(th) d following transplantation into soil. However, statistically significant differences in both type s of transgenic tobacco and control plants were not found during the a cclimation to ex vitro conditions.