Effects of Plant Growth Regulators on Rooting Capacity and Physiological and Biochemical Characteristic of Quercus nuttallii Cuttings

Softwood cuttings from 2a Quercus nuttallii mother plants were collected and treated with different plant growth regulators to determine the rooting rate, average number of new roots, length of new root and rooting index of cuttings. Cuttings treated with ABT solution which has the best rooting promoting efficiency was selected to determine the changes in soluble sugar content, soluble protein content, related enzymic activities, MDA content and endogenous hormones content during the rooting process of cuttings. The results showed that cuttings treated with 200 mg/kg ABT could promote rooting capacity. The rooting rate, average number of new roots, length of new root and rooting index of the cuttings treated with 200 mg/kg ABT were 33.30%, 1.91 per plant, 2.71 cm and 1.693 respectively, which were apparently higher than cuttings treated with 200 mg/kg IAA and 200 mg/kg NAA. During the rooting process, the content of soluble sugar decreased at first, then increased and then decreased, while the content of soluble protein increased at first and then decreased as a whole; There appeared 2 peaks in induction period of root primordium and elongation period of adventitious root in the activity of POD and PPO, being earlier than the control group; The activity of SOD and content of MDA both had a trend of increasing first and then decreasing; While the endogenous hormone content had a different trend but being higher than that of the control group. Plant growth regulators treatment can increase the nutrient content, related enzymic activities and endogenous hormones content in the cuttings, which can promote the rooting capacity of cuttings.