低温胁迫下玉米苗期根系保护酶活性及内源激素变化

摘要

为揭示不同抗冷性玉米品种幼苗根系保护酶活性及内源激素与品种抗寒性的关系，以耐低温型（郑单958），中间型（先玉335），低温敏感型（丰禾1）玉米品种为试验材料，分析幼苗根系在14℃/5℃、16℃/7℃、18℃/9℃、20℃/11℃（CK）4个温度梯度，处理2、4、6、8、10 d时根系保护酶SOD、POD活性、MDA含量及内源激素ABA、IAA、GA变化。结果表明，随着胁迫时间延长，不同温度处理下SOD、POD活性及MDA含量相对对照均呈上升趋势，SOD、POD活性表现为郑单958>先玉335>丰禾1，MDA含量变化为丰禾1>先玉335>郑单958。低温胁迫下ABA显著高于对照，IAA变化不显著，GA减少。表明品种间对低温存在抗（耐）性差异，幼苗在低温胁迫下根系生长受到抑制，但耐低温型品种自身调节能力较强，通过内源激素调节可保持根系正常生长，其中ABA在缓解低温胁迫伤害中起关键作用。%In order to reveal the protective enzyme activity, endogenous hormones in the seedling root and their relationships to low temperature stress, Zhengdan958(cold resistance type), Xianyu335(middle type), Fenghe1(sensitivity type) were investigated at diurnal temperature of 14 ℃/5 ℃, 16 ℃/7 ℃, 18 ℃/9℃, 20℃/11℃(CK)for 2, 4, 6, 8, 10 d, which analyzed the SOD and POD activities, MDA content and the change of ABA, IAA, GA. The results showed that SOD and POD activities were Zhengdan958>Xianyu335>Fenghe1, MDA content showed Fenghe1>Xianyu335>Zhengdan958. The results showed that with a prolonged stress under different temperature treatment, the activity of SOD, POD and the content of MDA in relative comparison were on the rise. The content of IAA changed insignificantly, the content of GA was decreased, which indicated that cold resistance type had higher ability to remove free radical and resulting to reduce the damage of membrane and keep plant metabolic. As low temperature inhibited the growth of root system, endogenous hormone adjustment could keep it grow normal y, which showed that resistant varieties had strong resist-ability to low temperature and ABA played a key role in relieving stress damage.