Effects of IBA on adventitious root development and the associated metabolic changes during softwood cutting rooting of sweet cherry rootstocks Gisela 6

In order to study the physiological mechanism underpinning the success of softwood cutting of sweet cherry rootstock Gisela 6 (Prunus cerasus × Prunus canescens), the effects of indole-3-butyric acid (IBA) on adventitious root development and changes of activities of peroxidase (POD), polyphenol oxidase (PPO), indoleacetic acid oxidase (IAAO), total soluble sugar content, total nitrogen content, and C/N ratio during rooting were investigated. The results showed that the rooting percentage, root numbers and the average root length increased significantly when treated by IBA. The treatment of 1000 mg L-1 IBA exhibited the best rooting responses. The rooting percentage, root numbers and the average root length were 81.2%, 10.5 and 2.95 cm, respectively. Compared with the control, they increased by 133.3, 262.1 and 45.3%, respectively. The activities of PPO and POD increased more significantly during the rooting period when treated by IBA. It also induced more total soluble sugar accumulation and increased C/N ratio. However, the total nitrogen content did not changed significantly. These results indicated that IBA increased rooting activities of Gisela 6 softwood mainly owing to the increase of the activities of PPO and POD, the total soluble sugar content and C/N ratio and the reduction of the IAAO activity.