摘要
为了探究低温对甜玉米种子萌发的影响以及不同品种抗寒性的差异机制,本研究以1组甜玉米自交系的种子为材料,通过低温胁迫下的萌发试验,筛选出耐寒性较强的1132和对低温敏感的国区T12,分别研究了其在10℃和26℃条件下萌发过程中超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)等3种抗氧化酶活性及其相关基因表达水平的变化。结果表明,耐寒自交系1132的抗氧化酶活性整体高于敏感系国区T12。随着低温胁迫时间的延长,1132吸胀萌发的种子中SOD、POD和CAT活性总体呈增加趋势,中间有波动,在胁迫后24h,3种酶的活性均高于常温对照;而国区T12在低温胁迫后SOD和POD大体为增加趋势,CAT则持续降低,在胁迫后24h只有SOD的活性高于常温对照。1132的SOD3、SOD9、CAT1相对表达量较国区T12高,虽未表现出与其酶活变化趋势严格一致,但低温胁迫使其整体表达呈先降低后增加趋势。2个品种的相对表达量均低,可能是POD3并非表达POD的关键基因,因此在酶活性和基因表达方面可能造成了两者抗寒性和发芽率的差异。综上,玉米种子萌发期的耐寒性与抗氧化酶活性密切相关,而抗氧化酶活性的变化则可能是一个非常复杂的表达调控过程。本研究结果不仅为鉴定和筛选耐低温种质资源、培育高发芽势种子提供理论和技术支持,同时为防御玉米低温引起的冷害提供参考。
In order to study the effect of seed germination and cold resistance mechanism differences of various sweet corn under coldness a set of sweet corn lines were used on germination test under cold stress. On the basis of the result of germination test, two lines （tolerant line 1132 and sensitive line GuoquT12） were screened out for study on changing trends of antioxidant enzyme （SOD, POD and CAT） activity and gene expression during seeds germination under 10℃ and 26℃. The results showed in general, antioxidant enzyme activity of tolerant line 1132 was greater than sensitive line GuoquT12. With the extension of time under low temperature, SOD, POD and CAT activity in the imbibed seeds of 1132 line showed a rising trend with some fluctuation, and exhibited higher antioxidant enzyme activity than control at 24h after stress. In contrast, SOD and POD activity of GuoquT12 displayed an increasing trend but CAT activity decreased. And only SOD activity exceed control at 24h after stress. Relative expression levels of SOD3, SOD9, CAT1 of the Variety 1132 were higher than GuoquT12 in spite of no strict consistency of the trend with their activities. On the whole chilling stress increased expression of SOD3, SOD9, CAT1 after the first decrease. While expression of POD3 had no consistency with POD both in 1132 and GuoquT12. POD3 may be not the key gene. The two factors may have contributed to the differences of the cold resistance and germination rate. The results indicated that cold tolerance of germinating seeds was closely related with antioxidant enzyme activity, however, change of antioxidant enzyme activity was likely a very complicated expression regulation process. This finding can not only provide theoretical and technical support for the identification and screening of low temperature germplasm resources, and cultivating high seed germination potential, but also provide reference for the defense of cold damage.
出处
《核农学报》
CAS
CSCD
北大核心
2016年第9期1840-1847,共8页
Journal of Nuclear Agricultural Sciences
基金
广东省教育部产学研结合项目(2012B091100467)
广东省科技攻关项目(2014B070706012)
广东省自然科学基金重点项目(080021003)
关键词
甜玉米
低温
萌发
抗氧化酶
基因表达
sweet corn, low temperature, germination, antioxidant enzyme, gene expression
