Abstract: In order to defi nite the eff ect of low light on enzymatic activity related to sweet corn quality and yield，this paper took sweet corn variety‘ Jingtian No.9’ as test material and studied the eff ects of diff erent shading rate and shading duration on sugar accumulation of sweet corn grain，sucrose synthesis-related enzymes and yield of sweet corn．The results showed that the activities of sucrose synthetase and sucrose phosphate synthase in leaf blades at ear position after fl owering，accumulation of sucrose and soluble sugar at each stage after fl owering，and yield of fresh plant ear were decreased gradually，manifested as：shading rate 30% ＞ shading rate 50% ＞ shading rate 80%．During the growth and development process of sweet corn，the activities of sucrose synthetase and sucrose phosphate synthase in ear leaves after anthesis，the accumulation amount of sucrose and soluble sugar in each stage after anthesis，and the fresh ear yield，their overall performance was：whole growth period shading ＜ big mouth to spinning period shading ＜ spinning till after spinning 25 d shading ＜ jointing to big mouth stage shading ＜ emergence to jointing stage shading．Under the combined action of diff erent shading rate and diff erent shading period，80% shading treatment during the whole growth period had the greatest effect on corn grain sugar accumulation and yield．In conclusion，different shading rate and diff erent shading period all could signifi cantly limit the yield and quality improvement of super sweet corn．Moreover，shading from big mouth to spinning period was a critical stage．

Key words: sweet maizecorn, low light stress, sucrose, synthetic enzyme, yield

摘要： 为明确弱光对甜玉米品质相关酶活性及产量的影响，以甜玉米品种晶甜9 号为试验材料，研究不同遮光率、不同遮光时期对甜玉米籽粒糖分积累、蔗糖合成相关酶及产量的影响。结果表明，随着遮光程度的加深，甜玉米穗位叶蔗糖合成酶和蔗糖磷酸合成酶的活性，花后各阶段籽粒蔗糖、可溶性糖积累量，以及鲜果穗产量均逐渐降低，表现为：遮光率30%＞遮光率50%＞遮光率80%。在甜玉米生长发育进程中，各时期遮光处理花后穗位叶蔗糖合成酶和蔗糖磷酸合成酶的活性，花后各阶段蔗糖、可溶性糖积累量，以及鲜果穗产量总体表现为：全生育期遮光＜大口至吐丝期遮光＜吐丝至吐丝后25 d遮光＜拔节至大口期遮光＜出苗至拔节期遮光。不同遮光率和不同遮光时期共同作用下，全生育期遮光80%处理对玉米籽粒糖分积累及产量的影响最大。综上，不同遮光率、不同遮光时期均显著限制了甜玉米的产量和品质提升，且大口至吐丝期遮光是关键时期。

关键词: 甜玉米, 弱光胁迫, 蔗糖, 合成酶, 产量