Abstract: Low temperature and drought are two abiotic stress factors that limit growth,development and yield of forage grass. Understanding the stress resistance mechanisms and breeding forage grass with strong cold and drought resistance is an important basis for the high-quality development of animal husbandry and the restoration of degraded grassland ecosystems in the cold and arid regions. At the morphological level,forage grass can form a variety of stress-resistant morphological structures under low temperature and drought stresses,and the changes of these morphological structures can reflect the response ability and adaptability of forage grass to adversity. At the physiological and biochemical level,forage grass can respond and adapt to low temperature and drought stresses by regulating superoxide dismutase,peroxidase,catalase,free proline,soluble sugar,soluble protein,abscisic acid,ethylene,gibberellin and cytokinin. At the molecular level,forage grasses adapt to cold and drought stresses through a combination of signaling transduction,response and resistance gene expression. In conclusion,this study reviewed the response and adaptive mechanisms of forage to low temperature and drought stresses from the levels of forage morphology,physiology and biochemistry and molecular level to provide an important reference for a comprehensive understanding of the stress resistant mechanisms of forage grass.

Key words: Low temperature, Drought, Stress resistance, Cold and dry regions, Grassland ecosystem

摘要： 低温和干旱是限制牧草生长发育和产量的两个非生物胁迫因子。掌握牧草抗逆性机制，选育具有强抗寒性和抗旱性的牧草是寒旱地区草牧业高质量发展和退化草地生态系统恢复的重要基础。在形态学层面，低温和干旱胁迫条件下牧草会形成多种抗逆性形态结构，这些结构的变化能很好地反映牧草对逆境的响应和适应能力。在生理生化层面，牧草通过调节超氧化物歧化酶、过氧化物酶、过氧化氢酶、游离脯氨酸、可溶性糖、可溶性蛋白质、脱落酸、乙烯、赤霉素和细胞分裂素等的响应，以适应低温和干旱胁迫。在分子水平层面，牧草通过信号转导、应答和抵御基因的表达等综合作用，以适应寒旱胁迫。总之，本研究从牧草形态学、生理生化和分子水平三个层面综述了牧草对低温和干旱胁迫的响应和适应机制，以期为全面认识牧草抗逆机制提供重要参考。

关键词: 低温, 干旱, 抗逆性, 寒旱地区, 草地生态系统