| 摘要 |
[Objectives] This study was conducted to investigate the regulatory effects of selenium (Se) on the content and balance of endogenous hormones and the function of antioxidant system during seed development in red sandalwood (Pterocarpus santalinus). [Methods] Two basic treatments, seven single-fertilization treatments, and four combined fertilization treatments were designed. Sampling was conducted at 2, 5, 8, and 18 weeks after flower withering to measure the embryo abortion percentage (EAP), the contents of three endogenous hormones (IAA, GA₃, ABA), and the activities of four antioxidant enzymes (CAT, APX, SOD, GR). [Results] Se application significantly inhibited embryo abortion in red sandalwood, with Na₂SeO₃ (Se (IV)) showing superior effects to Na₂SeO₄ (Se (VI)) and far exceeding the efficacy of individual applications of KCl, H₃BO₃, CO(NH₂)₂, Ca(H₂PO₄)₂, NPK compound fertilizer, or EFOF. The combined treatment of Se with NPK compound fertilizer and EFOF (EFOF+NPK compound fertilizer+Se (IV)) was the most effective, reducing the abortion percentage by 77.8% compared with UMC at 18 weeks after flower withering. Se application significantly increased the levels of three endogenous hormones and the (IAA+GA₃)/ABA ratio in red sandalwood seeds (including the embryonic stage). In the optimal treatment, the (IAA+GA₃) content was 240.7%, 256.4%, 353.7%, and 502.9% higher than that of UMC at 2, 5, 8, and 18 weeks after flower withering, respectively. Se application also concurrently enhanced antioxidant enzyme activities, with all four antioxidant enzymes in seeds of Se-treated plants showing significant increases. Notably, the selenoenzyme GR maintained considerably high activity even at 18 weeks after flower withering. The embryo abortion percentage was highly significantly negatively correlated with IAA content and GR activity, identifying IAA and (IAA+GA₃) content as key hormonal indicators and GR as the core antioxidant enzyme, together constituting the central regulatory factors. The results indicate that Se suppresses embryo abortion in red sandalwood through a dual regulatory pathway: by elevating IAA and GA₃ levels along with the (IAA+GA₃)/ABA ratio to optimize hormonal signaling networks, and by enhancing the activities of antioxidant enzymes such as GR to alleviate oxidative stress induced by cool-season low temperatures. [Conclusions] This study provides a theoretical basis and technical strategy for precision fertilization and stress resistance management in the cultivation of red sandalwood. |
