Responses of the photosynthetic system and peroxidase activity to the rooting conditions of oak micropropagation

The effects of indole butyric acid (IBA) concentration and the duration of the plant growth regulator (PGR) treatment on the rooting ability, peroxida se level and photosynthetic activity of young Quercus robur L. plants were studied. Four-week-old oak shoots were transplanted to rooting media supple mented with 10 or 20 muM IBA. After 2, 3, 4, 5 or 7 days the shoots were tr ansplanted again to a fresh, PGR-free medium. On the tenth day after transf er to rooting medium, the CO2 fixation capacity, pigment content and peroxi dase activity were measured. The photosynthetic parameters varied as a func tion of the time spent on medium containing PGR, showing maximum values in plants transplanted on the third to fourth day to PGR-free medium. The root ing percentage of these plants reached its maximum within two weeks. Howeve r, peroxidase activity was the highest in plants transferred later to PGR-f ree medium. The most pronounced stimulating effect on rooting was achieved with the higher initial IBA concentration followed by a transfer to PGR-fre e medium on the third to fourth day. These plants showed the highest vitali ty and the best rooting ability.