Studies On Formation Of Adventitious Roots And Rooting Mechanism Of Spd In Chrysanthemum

Cutting propagation was the main breeding method of many ornamental plants. Adventitious root formation was the key step to the success of cutting what were controlled by both the endogenous and exogenous factors. The poor root quality of precious species often causes loss to producer.This research took chrysanthemum as materials which rooted easily. At the beginning of the experiment, the optimum concentration of Spd was identified. Then the influence of excess and insufficient Spd on chrysanthemum cuttings rooting and the relationship between polyamine and endogenous hormones and nutrients and related oxidases were studied, and the physiological mechanism of Spd regulating the root development was discussed to provide theoretical basis and technical support to improve the ability of cuttings rooting of rare species.Totally the result were showed as the following aspects:1. The results demonstrated that 0.05 mmol·L-1 of exogenous Spd application was the optimum concentration to promote adventitious rooting. The cutting took root 2 days in advance compared to the control. The maximum root length, average root length, total root number, root volume, root index, seedling index respectively increased by 22.72%、14.81%、27.27%、64%、27.07%、18.56% compared with CK. The condition of rooting was improved with Spd treatment after applying DCHA which was similar to that of control.2. Exogenous Spd increased the accumulation of chlorophyll, soluble sugar, starch and soluble protein during rooting in the chrysanthemum cuttings with contrary to DCHA treatment. The results showed that the content of soluble sugar, soluble protein and starch increased first and then decreased in the early stage of chrysanthemum cuttings rooting, indicating that adventitions root formation needs nutrients. In the early stage of cuttings, the contents of chlorophyll, starch, soluble sugar and soluble protein decreased at first and then the content of soluble sugar rose after the formation of adventitious root.3. Exogenous Spd treatment induced the increase of IAA, the ratios of IAA/ABA and IAA/ZR, resulting in the decrease of ABA, ZR, JA. The result of exogenous DCHA treatment leaded to the opposite effect compared to Spd treatment, and Spd treament relieved the rooting inhibition induced by DCHA inhibitor.4. Exogenous Spd treatment induced the increase of POD and PPO activity with contrary to DCHA treatment. The activity of POD began to rise after 6 h treatment with Spd and reached the peak in 15 th day. And the POD activity showed a declined tendency with four treatments after 15 days. The acivity of PPO reached the peak in 12 th hour after chrysanthemum cuttings treatment except DCHA, During 0 and 15 d after cutting, PPO activities of all four treatments significantly increased and then decreased largely in 15 th day.