【摘要】 为揭示玉米在萌发期和苗期对低温胁迫的生理响应机制，以黑龙江省农业科学院玉米研究所提供的19份玉米杂交种为试验材料，采用5℃低温胁迫，测定玉米萌发期的发芽率及苗期的株高、鲜质量、干质量、根鲜质量和根干质量等指标，对玉米的耐低温能力进行综合评价。结果表明，低温胁迫后，所有杂交种的发芽率均显著降低，平均下降幅度达59.30%,且不同品种间存在显著差异。低温条件能够显著抑制玉米幼苗株高、鲜质量和干质量，且不同品种的抗逆能力存在差异。利用隶属函数法进行综合评价显示，龙单125耐低温能力最弱，而龙单313表现出最强的耐低温性。进一步测定低温抗感材料在苗期的超氧化物歧化酶、过氧化氢酶、丙二醛、可溶性糖及根系活力等生理生化指标，结果表明，低温胁迫显著抑制了玉米种子的萌发率，导致幼苗生长受限及生物量积累减少。同时，低温条件下，保护酶活性显著提升，渗透调节物质含量增加，膜脂过氧化水平升高，根系活力降低。更多还原

【Abstract】 In order to reveal the physiological response mechanisms of maize during the germination and seedling stages under low-temperature stress, this study utilized 19 maize hybrids provided by the Maize Research Institute of Heilongjiang Academy of Agricultural Sciences as experimental materials. A low-temperature stress of 5 ℃ was applied to assess the germination rate during the germination period and various indicators at the seedling stage, including plant height, fresh weight, dry weight, root fresh weight, and root dry weight, to comprehensively evaluate the cold tolerance of maize. The results demonstrated that low-temperature stress significantly reduced the germination rate of all hybrids, with an average decrease of 59.30%, and there were significant differences among different varieties. Low-temperature conditions significantly inhibited seedling height, fresh weight, and dry weight, and the stress resistance varied among different varieties. Comprehensive evaluation using the membership function method showed that Longdan 125 had the weakest low-temperature resistance, while Longdan 313 exhibited the strongest low-temperature resistance. Further analysis of the physiological and biochemical indices, including superoxide dismutase, peroxidase, malondialdehyde, soluble sugars, and root vitality, demonstrated that low-temperature stress significantly inhibited seed germination rates, leading to restricted seedling growth and reduced biomass accumulation. Additionally, under low-temperature conditions, the activities of protective enzymes were significantly enhanced, the content of osmotic adjustment substances increased, membrane lipid peroxidation levels rose, and root vitality decreased.更多还原