Effect of Paclobutrazol on Cold-resistance of Dalbergia odorifera Container Seedlings

The one-year container seedlings of Dalbergia odorifera were treated with different concentrations, alternative methods and treatment time of paclobutrazol. The growth and physiological indexes during overwintering were analyzed, and the optimal treatments of the seedlings for the overwintering growth and physiological responses to cold were explored. The results showed that the decrease value of height-to-diameter ratio and shoot-to-root ratio and lignification of the seedlings treated with different paclobutrazol were higher than those of CK. It was observed that soluble sugar, soluble protein content and SOD activity of the leaves increased, but MDA and relative conductivity decreased compared to CK. Based on our comprehensive evaluations, it appeared that the effect of 1 000 mg/L of soil application on November 15 and 1 500 mg/L on November 30 and 1 000 mg/L of leaf spray on November 15 produced better results.