Peroxidase (PO: E. C 1.11.1.7) and IAA. Oxidase (IAA-O) enzyme activities were investigated during rooting in cuttings of Populus nigra L., Populus alba L. and Populus tremula L. ( Salicaceae), and the relations between enzyme activities and rooting ability were examined comparatively. PO activity started to increase the early stages of primordium formation and reached the highest level before root emergence. However, no apparent correlation was found between the activity of PO and the ability of the cuttings to form roots. IAA-O activity was observed only in root cuttings of P. alba and P. nigra. Activity increased after day 6 and reached the highest level at the stages of root emergence. A positive correlation between rooting and IAA-O activity was observed.

Peroxidase (PO: E. C 1.11.1.7) and IAA. Oxidase (IAA-O) enzyme activities were investigated during rooting in cuttings of Populus nigra L., Populus alba L. and Populus tremula L. ( Salicaceae), and the relations between enzyme activities and rooting ability were examined comparatively. PO activity started to increase the early stages of primordium formation and reached the highest level before root emergence. However, no apparent correlation was found between the activity of PO and the ability of the cuttings to form roots. IAA-O activity was observed only in root cuttings of P. alba and P. nigra. Activity increased after day 6 and reached the highest level at the stages of root emergence. A positive correlation between rooting and IAA-O activity was observed.