摘要： 为了探讨外源ABA对玉米苗期耐寒性的影响，选取了耐寒能力强的青农105和冷敏感的农华101为试验材料，对其进行低温和外施ABA处理后，测定2个玉米品种的MDA含量、相对电导率、可溶性糖含量、保护酶活性和激素含量，并通过荧光定量PCR对低温胁迫相关基因的表达量进行了比较。结果表明，外源ABA处理降低了低温胁迫下2个玉米品种的MDA含量和相对电导率，提高了可溶性糖含量。抗寒品种青农105的MDA含量和电导率下降幅度大，而可溶性糖含量上升幅度大，外源ABA对抗寒性强的青农105作用更明显。对植物体内保护酶活性和激素含量分析发现，外源ABA可以提高低温胁迫下2个品种的SOD、POD、CAT、APX活性，增强清除活性氧的能力，减少活性氧物质的积累，抗寒品种青农105的SOD、POD、CAT、APX活性增幅较大，外源ABA对抗寒品种青农105作用更明显。外源ABA处理明显提高了低温胁迫下2个玉米品种的内源ABA的含量，降低了GA₃、ZR、IAA含量，低温及ABA处理对抗寒品种青农105作用更明显。分子水平的证据表明，外源ABA处理增强了低温条件下一些与逆境胁迫相关基因的表达。对青农105和农华101的抗寒基因分析表明，低温胁迫诱导2个品种的Apx1、Fad8、Lip15、Cat3基因及抗寒品种青农105的Dreb1和Asr1基因的表达，抑制冷敏感品种农华101的Dreb1和Asr1基因的表达，结果发现，外施ABA对耐寒性强的玉米品种作用明显。为我国北方地区春玉米的生产提供了一些抵御冷害的策略。

关键词: 玉米, ABA, 低温, 抗寒性

Abstract: In order to explore the influences of exogenous ABA on cold resistance of maize,we selected two maize materials(cold resistant Qingnong 105 and the cold sensitive agricultural Nonghua 101 as the experimental materials)were used as the experimental materials,after the treatment of low temperature and external application of ABA. The MDA content,relative conductivity,soluble sugar content,protective enzyme activity and hormone content of two maize varieties were determined,and the expression of low temperature stress related genes was compared by fluorescent quantitative PCR. The results showed that the content of MDA and relative conductivity of two maize varieties under low temperature stress were reduced by exogenous ABA treatment,and the content of soluble sugar was increased. The MDA content and conductivity of the cold resistant cultivar Qingnong 105 decreased greatly,while the soluble sugar content increased greatly,Exogenous ABA played a more significant role in the cold resistance of Qingnong 105. By analysis of enzyme activities and hormone levels,exogenous ABA could improve SOD,POD,CAT,APX activities caused by low temperature stress and enhance the ability of active oxygen in order to reduce the accumulation of reactive oxygen species. Exogenous ABA had more obvious effect on Qingnong 105 than Nonghua 101 because Qingnong 105 possessed stronger increase in SOD,POD,CAT,APX activities. We found that exogenous ABA application increased endogenous ABA biosynthesis under low temperature stress,simultaneously reduced the levels of GA₃,ZR,IAA. The effect of low temperature and ABA treatment on cold-resistant cultivar was more obvious. Molecular evidence from RT-PCR showed that exogenous ABA increased the expression level of some genes involved in abiotic stresses under low temperature stress. By comparison of the capacity of these two varieties to low temperature,low temperature stress leads to upregulated Apx1, Fad8, Lip15, Cat3 gene in these two varieties,also Dreb1, Asr1 gene in Qingnong 105,but downregulated Dreb1, Asr1 gene in Nonghua 101. We found that external application of ABA had a significant effect on cold resistant maize varieties. The data could provide some strategies to avoid damages from chilling injury for maize production in China North Area.

Key words: Maize, ABA, Low temperature, Cold resistance

中图分类号: 

• S513.01