【摘要】 为研究施加外源甜菜碱在低温胁迫下对种子萌发过程，尤其是萌发过程中呼吸作用的影响，以高丹草品种‘优牧2号’为试验材料，分析甜菜碱（glycine betaine,GB）对低温胁迫下高丹草种子萌发过程中呼吸电子传递及其幼苗生长的作用。结果表明，15 mmol/L GB处理可显著提高高丹草种子低温萌发的发芽率、发芽势、发芽指数、芽长和根长；显著提高高丹草种子低温萌发的总呼吸速率、COX呼吸速率、AOX呼吸速率和COX在总呼吸中的占比，对AOX在总呼吸中的占比无显著影响，但随着温度的增加对AOX呼吸和COX呼吸在总呼吸中的占比的影响逐渐减小；显著提高高丹草种子低温萌发的SOD活性、POD活性和CAT活性，显著降低其H₂O₂含量。15 mmol/L GB处理可显著提高高丹草幼苗的株高、根长、茎长、叶长、总鲜质量、地上部鲜质量、地下部鲜质量和根冠比，显著提高高丹草幼苗的SOD活性、POD活性和CAT活性，显著降低其H₂O₂含量。15 mmol/L GB处理下高丹草种子低温萌发的发芽率、发芽势、发芽指数、芽长、根长均与总呼吸速率、COX呼吸速率、AOX呼吸速率呈极显著或显著的正相关关系，与CAT活性、SOD活性、POD活性和H₂O₂含量呈极显著或显著的负相关关系。15 mmol/L GB处理下高丹草幼苗低温生长的株高、根长、茎长、叶长均与总鲜质量、地上部鲜质量、地下部鲜质量呈极显著或显著的正相关关系，与H₂O₂含量呈极显著或显著的负相关关系。因此，甜菜碱可以增加种子内COX和AOX的呼吸速率，提高种子和幼苗的抗氧化酶活性，减少其活性氧的产生，有效缓解低温胁迫对种子和幼苗的氧化伤害，促进高丹草种子在低温胁迫下的萌发及其幼苗在低温胁迫下的生长发育。更多还原

【Abstract】 The paper aims to investigate the effect of exogenous glycine betaine on seed germination, especially the respiration during germination, under low temperature stress. This study used the Sorghum bicolor × S.sudanense variety‘Youmu 2’as the experimental material to investigate the effects of glycine betaine（GB） on respiratory electron transfer during seed germination and seedling growth under low temperature stress. The results indicated that: 15 mmol/L GB treatment significantly increased the germination potential, germination index, germination rate, shoot length, and root length of Sorghum bicolor × S. sudanense seeds during lowtemperature germination. It also significantly increased the total respiration rate, COX respiration rate, AOX respiration rate, and the proportion of COX in the total respiration of Sorghum bicolor × S. sudanense seeds during low-temperature germination. However, it had no significant effect on the proportion of AOX in the total respiration. Its effect on the proportion of COX respiration and AOX respiration in total respiration gradually decreased with increasing temperature, significantly increasing the SOD activity, POD activity, and CAT activity of Sorghum bicolor × S. sudanense seeds during low-temperature germination, and significantly reducing their H₂O₂content. It significantly improved the SOD activity, POD activity, and CAT activity of Sorghum bicolor × S. sudanense seeds during low-temperature germination, and significantly reducing their H₂O₂content. The germination rate, germination potential, germination index, shoot length, and root length of Sorghum bicolor× S. sudanense seeds under low temperature germination with 15 mmol/L GB treatment showed a highly significant or significant positive correlation with AOX respiration rate, COX respiration rate, and total respiration rate, and a highly significant or significant negative correlation with CAT activity, SOD activity,POD activity, and H₂O₂content. The plant height, root length, stem length, and leaf length of Sorghum bicolor×S. sudanense seedlings grown at low temperatures under 15 mmol/L GB treatment showed a highly significant or significant positive correlation with total fresh mass, aboveground fresh mass, and underground fresh mass, and a highly significant or significant negative correlation with H₂O₂content. Therefore, GB could increase the respiration rate of COX and AOX in seeds, enhance the antioxidant enzyme activity of seeds and seedlings,reduce the production of reactive oxygen species, effectively alleviate the oxidative damage to seeds and seedlings under low temperature stress, promote the germination of Sorghum bicolor× S. sudanense seeds and the growth and development of its seedlings under low temperature stress.更多还原