外源腐殖酸浸种对盐胁迫下蒙古黄芪种子萌发及幼苗生长的影响

Effect of exogenous humic acid soaking on seed germination and seedling growth of Astragalus membranaceus under salt stress

摘要:

【目的】探究外源腐殖酸(HA)浸种对盐胁迫下蒙古黄芪种子萌发及幼苗生长的影响。【方法】以蒙古黄芪种子为试验材料,筛选出与对照相比能使50%蒙古黄芪种子萌发的NaCl浓度,研究外源HA浸种对此浓度NaCl胁迫下蒙古黄芪种子萌发和幼苗生长的最适缓解浓度。【结果】与对照相比,75 mmol/L NaCl使50%蒙古黄芪种子萌发受到抑制,外源HA浸种可显著缓解NaCl胁迫对蒙古黄芪种子萌发造成的抑制作用。与HA0组相比,0.4 g/L HA处理对NaCl胁迫下种子萌发的促进作用最为显著,其发芽率、发芽势、发芽指数和平均发芽速率分别升高107.1%、75.75%、92.97%、98.69%;较HA0组相比,0.2和0.4 g/L HA浸种处理对蒙古黄芪幼苗胚根长度、胚轴直径生长有显著促进作用;幼苗中丙二醛(MDA)、可溶性蛋白(SP)和脯氨酸(Pro)含量显著降低,而叶绿素(CHL)含量显著升高,其中0.4 g/L HA处理对幼苗生长的促进效果最佳。【结论】0.4 g/L HA浸种处理能显著缓解75 mmol/L NaCl胁迫对蒙古黄芪种子萌发和幼苗的毒害作用。该结论为蒙古黄芪规范化种植中出现的盐胁迫问题提供理论依据。

Abstract:

【Objective】To investigate the effects of exogenous humic acid (HA) seed soaking on the seed germination and seedling growth of Astragalus membranaceus under salt stress.【Method】Using Astragalus membranaceus seeds as experimental materials, the NaCl concentration that could induce 50% seed germination compared to the control was screened, and the optimal alleviating concentration of exogenous HA seed soaking on seed germination and seedling growth under this specific NaCl stress was investigated.【Result】A concentration of 75 mmol/L was the NaCl concentration that caused 50% germination of Astragalus membranaceus seeds compared to the control group. Furthermore, exogenous HA seed soaking significantly alleviated the inhibitory effect of NaCl stress on seed germination. Compared with HA0 group, the 0.4 g/L HA treatment exhibited the most significant promoting effect on seed germination under NaCl stress, with its germination rate, germination potential, germination index and average germination rate increased by 107.1%、75.75%、92.97%、98.69%, respectively. Compared with the HA0 group, soaking seeds in 0.2 and 0.4 g/L HA brassinazole significantly promoted the growth of radicle length and embryonic axis diameter in A. membranaceus seedlings. Additionally, the contents of malondialdehyde (MDA), soluble protein (SP), and proline (Pro) in the seedlings significantly decreased, while the content of chlorophyll (CHL) significantly increased, with the 0.4 g/L HA treatment showing the best promoting effect on seedling growth.【Conclusion】Soaking seeds in 0.4 g/L HA can significantly alleviate the toxic effects of 75 mmol/L NaCl stress on the seed germination and seedlings of Astragalus membranaceus. This conclusion provides a theoretical basis for the salt stress problem encountered in the standardized cultivation process of Astragalus membranaceus.