Peroxidase, polyphenol oxidase (PPO), phenolic compounds and total sugars (TS) were investigated during root formation in cuttings of Berberis vulgaris var. asperma (BVA) and Berberis thunbergii var. atropurpurea (BTA) treated with indole-3-butyric acid (IBA) and IBA + H2O2. Rooting was observed on BTA cuttings but not on BVA cuttings. The BTA cuttings treated with IBA and IBA + H2O2 showed higher rooting percentages, number of roots, and root length over the control. Those treated with IBA + H2O2 recorded the lowest peroxidase activity after planting. BTA cuttings treated with IBA + H2O2 showed the highest peroxidase activity at 50 d after planting; BVA cuttings under different treatments showed no significant difference for peroxidase activity at planting time or up to 80 d after planting. PPO activity for the BTA cuttings in the control treatment was lower than for other treatments during root formation. The cuttings in the IBA and IBA+H2O2 treatments showed increased PPO activity from 0 to 50 d after planting and a slight decrease in PPO activity from 60 to 80 d after planting. PPO activity for the BVA cuttings was significantly lower than for BTA during root formation. The BTA cuttings treated with IBA and IBA + H2O2 showed the highest phenolic compound content during root formation. The BVA cuttings displayed higher TS than BTA during the initial stage of root formation. A comparison of the anatomical structure of easy-to-root and difficult-to-root cuttings indicated that physical inhibitors did not affect the rooting capacity of BVA.

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