The aim of this study was to investigate the effects of exogenous gibberellin (GA3) and uniconazole (S3307) on the growth of C. oleifera spring shoots, and ultimately to seek ways to improve the quality of its panicles. Five-year-old ‘Huaxin’ trees were sprayed with 2400 mg/L GA3 or 800 mg/L S3307 at the leaf expansion stage. Growth parameters, physiological indicators, and endogenous hormone levels were measured. The results showed that GA3 significantly enhanced shoot extension and internode lengthening, whereas S3307 treatment exhibited the opposite inhibitory effects. GA3 treatments increased the content of soluble sugar, enhanced the activity of SOD and POD, decreased the activity of CAT, decreased MDA accumulation, indicating that membrane lipid peroxidation was alleviated. The results of endogenous hormone analysis indicated that GA3 and S3307 reduced the concentration of ABA and IAA, increased the content of tZ, and altered the distribution of endogenous GA3. Overall, GA3 enhanced spring shoot growth by regulating endogenous hormone balance, enhancing nutrient accumulation and antioxidant capacity. These results provide the theoretical and technical basis for the high-quality spike formation and high-yield of cultivation of C. oleifera.
Xu et al. (Sat,) studied this question.