Growth and Physiological Changes in Amorpha fruticosa Linn. Seedlings Following Paclobutrazol Treatment

Using pot experiments, the growth and physiological changes in Amorpha fruticosa Linn. seedlings following treatment with different paclobutrazol (PP₃₃₃) concentrations (1, 5, 10, 15 and 20 mg/L) were investigated to clarify the mechanism and best treatment. In the range of 1-20 mg/L, with the increase in PP₃₃₃ concentration, tree height, leaf area and taproot length showed a declining trend, whereas base diameter, leaf length to width ratio, fresh weight of root, and root-shoot ratio showed an increasing trend. Relative water content, chlorophyll, soluble sugar and soluble protein content in leaves were effectively increased, POD activity was effectively enhanced, and MDA content and relative conductivity were effectively reduced compared with that in the control. Using the membership function to evaluate the regulation effect of each treatment, A. fruticosa seedlings had the strongest resistance with 20 mg/L PP₃₃₃. Our study indicated that, by adjusting biomass allocation, moisture content, cell permeability and oxidation resistance of A. fruticosa seedlings, PP₃₃₃ effectively improved growth and physiological characteristics, and thus the resistance of A. fruticosa seedlings was improved. This study offers a theoretical basis for the application of PP₃₃₃ in plant and vegetation slope restoration.