播种至苗期不同阶段冻害与持续时间对玉米幼苗建成及抗性生理的影响

Effects of Freeze Injury with Different Phases and Various Durations between Sowing and Seedling Periods on Growth and Resistant Physiological of Maize Seedlings

以先玉335为供试品种,基于寒地典型玉米种植生态区的田间温度动态,采用两因素完全随机设计,分别设置冻害发生阶段和冻害持续时间处理,比较分析各处理组合条件下玉米幼苗形态建成及抗性生理指标的变化差异。研究表明,玉米播种至出苗各阶段发生冻害胁迫后,可不同程度延长玉米出苗时间、降低成苗率,甚至导致幼苗全部死亡。播后早期冻害通过降低种子贮藏物质转运效率,加剧膜脂过氧化,削弱叶片光能捕获能力等一系列不可逆影响,抑制幼苗形态建成,这些不利影响程度随冻害持续时间的延长而不断加强。播后冻害可诱导存活植株体内可溶性蛋白、脯氨酸、可溶性糖等渗透调节物质含量维持较高水平,以改善植株对低温环境的适应能力。玉米播种至出苗各阶段受冻害胁迫影响均较显著,且以播种10 d后植株对冻害最为敏感。

The experiment was conducted with Xianyu 335 as the test variety.Based on the field temperature dynamics of typical maize planting ecological area in cold region,two factors completely random design was adopted to set the occurrence stage of freezing injury and the duration of freezing injury respectively.The morphogenesis and resistant physiological indexes of maize seedling were compared and analyzed.The results showed that freezing stress at different stages from sowing to emergence could prolong the emergence time,reduce the seedling rate,and even lead to the death of all seedlings.Freezing injury at early stage after sowing also could cause a series of irreversible effects by reducing the transport efficiency of seed storage materials,aggravating the degree of membrane lipid peroxidation,and weakening the ability of light energy capture of leaves,inhibiting the morphogenesis of seedlings.The extent of these adverse effects is increasing with the extension of freezing injury duration.At the same time,freezing injury after sowing can induce the osmoregulation substantive contents of soluble protein,proline,and soluble sugar in the survival plants to maintain a high level,to improve the adaptability of plants to low temperature environment.Maize was significantly affected by freezing stress at all stages from sowing to emergence,and the plants 10 days after sowing were the most sensitive to freezing stress.