高温胁迫对‘黄冠’、‘翠玉’梨耐热生理指标及相关基因表达的影响

Effects of High Temperature Stress on Heat Resistance and Related Genes Expression of Pear Trees

摘要:

为探讨高温胁迫对梨树的影响，对2年生‘黄冠’（Pyrus pyrifolia ‘Cuiguan’）、‘翠玉’（P. bretschneideri×P. pyrifolia）盆栽苗胁迫后叶片的抗氧化物质、抗氧化酶、渗透物质和激素的变化进行了测定，利用qRT-PCR分析了叶片中抗性基因的表达。结果表明，在高温胁迫下，梨树叶片的叶绿素含量明显下降，而MDA含量则持续上升；梨叶片中的POD和CAT活性总体呈下降趋势，但‘黄冠’的POD和CAT活性均高于‘翠玉’；PRO含量随胁迫时间延长逐渐增加；ASA含量表现出先上升后下降，且‘黄冠’的ASA含量高于‘翠玉’；IAA和ABA含量都随胁迫时间的延长呈下降趋势，但‘黄冠’的IAA和ABA含量比‘翠玉’高。qRT-PCR结果表明，叶片中相关基因的表达量与对应的ASA、IAA和ABA含量变化趋势基本一致。因此，‘黄冠’比‘翠玉’抗高温性能强，且高温处理第4天为‘黄冠’和‘翠玉’梨的生理变化转折点。

Abstract:

To understand the effect of high temperature stress on Pyrus trees, the changes in antioxidant substance, antioxidant enzymet and osmotic substance in leaves of 2-year-old ‘Huangguan’ (P. pyrifolia ‘Cuiguan’) and ‘Cuiyu’ (P. bretschneideri×P. pyrifolia) seedlings were measured, and the expressions of related genes at different stages were analyzed by qRT-PCR. The results showed that under high temperature stress, the chlorophyll content in leaves of ‘Huangguan’ and ‘Cuiyu’ reduced, while MDA content gradually increased. The activities of POD and CAT in two cultivars were both reduced, but those in ‘Huangguan’ were higher than in ‘Cuiyu’. The Pro content in two cultivars was increased with stress time. And the ASA content increased at first and then decreased in two cultivars. The contents of IAA and ABA decreased with stress time in two cultivars, but those in ‘Huangguan’ were higher than in ‘Cuiyu’. The expressions of related genes in leaves were consistent with the changes in contents of ASA, IAA and ABA. Therefore, the heat resistance of ‘Huangguan’ was stronger than that of ‘Cuiyu’, and the turning point of physiological change in two cultivars was the fourth day under high temperature.