Ethylene in relation to protein, peroxidase and polyphenol oxidase activities during rooting in hazelnut cotyledons

During formation of adventitious roots, the effects of 2-chlorethylphosphonic acid (CEPA), 1-aminocyclopropane-1-carboxylic acid (ACC) and aminoethoxyvinylglycine (AVG) added to a Cheng basal medium, supplemented with indole-3-butyricacid (IBA) and kinetin were determined on peroxidase (PO; EC 1.11.1.7) and poiyphenol oxidase (PPO; EC 1.10.3.1) activities in cotyledon explants of hazelnut ( Corylus avellana L. cv. Casina). CEPA stimulated PO and PPO activities while AVG inhibited. SDS-polyacrylamide gel electrophoresis of preparations from hazelnut cotyledons showed a correlation between proteins and rooting. Ethylene seems to modify total protein content and the activities of PO and PPO. As compared to the control extracts, AVG inhibited the anodic (53, 30.7 and 27 kDa) and cathodic (66.2 and 53.4 kDa) isoperoxidases and anodic (27.5 and 21 kDa) and cathodic (67.5 kDa) isopolyphenol oxidases, whereas CEPA promoted the anodic (30.7, 28.8 and 27 kDa) and cathodic (53.4 and 27.2 kDa) isozymes with PO activity. The increased PO activity during rooting in hazelnut cotyledons could enhance isozymes with lignin biosynthetic activity.