PHOTOSYNTHETIC CHARACTERISTICS OF SOLANUM-TUBEROSUM L PLANTS TRANSFORMED BY AGROBACTERIUM STRAINS .2. PHOTOSYNTHETIC ACTIVITIES

Photosynthetic and growth characteristics of the control potato plants cv. Zvikov and those transformed by Agrobacterium were compared durin g their cultivation in vitro in agar medium with 1% saccharose, after having been transplanted into pots with soil, or growing from tubers i n soil. The average leaf area, fresh and dry matter, chlorophyll a and b ratio, and contents calculated per fresh and dry matter of the leaf area were significantly higher in the control plants raised from tube rs and in vitro cultivated than in the transplanted ones. The signific ant increase in oxygen evolution by leaf fragments was found only in t he control potato plants raised from tubers. Differences between photo chemical activities of chloroplasts isolated from control and transfor med plants were statistically significant only when calculated per fre sh leaf matter. Chloroplasts from transformed potato plants grown from tubers and from those cultivated in vitro exhibited higher activities of photosystems (PS) 2 and PS 1 independently on the donors and accep ters of electrons used. On the contrary, higher activities of both pho tosystems were found in chloroplasts isolated from the control plants transferred to soil.