摘要：干旱是影响作物正常生长发育的一个最重要的逆境因子，水资源日益短缺成为制约农业发展的严重问题。本实验以干旱敏感玉米品种B73、Lo1016和耐干旱玉米品种Lo964、Va35为实验材料，采用盆栽控水的方法，研究了不同梯度的干旱胁迫对玉米苗期抗氧化系统的影响。结果表明，经干旱处理的幼苗超氧阴离子自由基含量，过氧化氢含量和超氧化物歧化酶（SOD）活性，过氧化氢酶（CAT）活性与对照组相比都有显著变化，幼苗体内超氧阴离子自由基含量呈上升趋势，在干旱处理阶段（D-9）达到峰值；过氧化氢含量变化趋势与超氧阴离子自由基相似，在干旱处理第三阶段（D-9）达到峰值；玉米苗期SOD活性随着干旱程度增加，呈先上升后下降的趋势，干旱敏感玉米品种B73、Lo1016在第一阶段（D-3）就出现峰值，表明其对环境变化敏感，而耐干旱玉米品种Lo964、Va35分别在第二阶段，第三阶段出现峰值，同时CAT活性也呈先上升后下降趋势，与SOD有相似的变化。上述结果表明，干旱胁迫诱导了敏感玉米品种中较早地积累了过量的活性氧种类，并较早地激活了活性氧清除酶系的活性,而在耐干旱品种中活性氧呈现逐步积累，其清除酶系启动相对较晚。62462

毕业论文关键词：玉米，干旱胁迫，超氧阴离子自由基含量，过氧化氢含量，超氧化物歧化酶，过氧化氢酶

Abstract: Drought stress affects the normal growth and development of maize. As one of the most important factor of environmental stress , water shortage is becoming a serious problem restricting the development of agriculture. This experiment used drought sensitive maize varieties B73, Lo964 Lo1016 and drought resistant maize variety, Va 35 for studying Influence of drought stress.  The reactive oxygen species and their scavenging enzymes were investigated following the process of drought treatment on the leaves of corn seedling. The results showed that the contents of superoxide anion and hydrogen peroxide and the activities of SOD and CAT compared with the control group had significant changes. reactive oxygen species, including super oxygen anion free radicals and Hydrogen peroxide showed a rapidly rise trend; activites of SOD and CAT showed a similar change trend in drought-sensitive maize varieties B73, Lo1016. But they displayed a progressively increase patterns in drought- resistant maize varieties Lo964, Va35.The results showed that drought stress induced the sensitive maize varieties in early accumulated excess reactive oxygen species, and early activation of the avtive oxygen removal of the activity of the enzyme system, and reactive oxygen species present gradually accumulated in the drought resistant varieties, the removal of enzyme system started relatively late.

Keywords:corn,droughtstress, superoxide radical content,hydrogen peroxide content,super oxide dismutase,catalase

1 前言 4

2材料与方法 5

2.1试验材料 5

2.2盆栽实验 5

2.3测定项目及方法 5

2.3.1.超氧阴离子自由基含量测定 5

2.3.2 过氧化氢含量测定 5

2.3.3 SOD活性测定 5

2.3.4 CAT活性测定 6

3.结果与分析 6

3.1干旱胁迫对超氧阴离子自由基含量的影响 6

3.2干旱胁迫对过氧化氢含量的影响 7

3.3干旱胁迫对SOD活性的影响 8