外源亚精胺对NaCl胁迫下黄瓜幼苗多胺代谢的影响

Effects of exogenous spermidine on polyamine metabolism in cucumber (Cucumis sativus L.) seedlings under NaCl stress

本文采用营养液水培,研究外源亚精胺(Spd)对NaCl胁迫下抗盐能力不同的两个黄瓜品种幼苗体内多胺(PAs)含量及PAs代谢关键酶活性的影响。结果表明,50mmol·L^(-1)NaCl溶液胁迫下黄瓜幼苗叶片和根系中精氨酸脱羧酶(ADC)、鸟氨酸脱羧酶(ODC)、s-腺苷蛋氨酸脱羧酶(SAMDC)和多胺氧化酶(PAO)活性显著升高,引起腐胺(Put)、亚精胺(Spd)和精胺(Spm)含量显著增加,且存在品种差异,抗盐性较强的‘长春密刺’Spd、Spm含量和ADC、ODC、SAMDC活性升高幅度均大干抗盐性较弱的‘津春2号’,而Put含量和PAO活性升高幅度却小于‘津春2号’。外源0.1 mmol·L^(-1)Spd溶液处理促进ADC、ODC和SAMDC活性迅速升高,显著提高了幼苗Spd和Spm含量,降低了Put含量和PAO活性,且对‘津春2号’影响更明显。表明NaCl溶液胁迫下外源Spd参与了黄瓜幼苗体内内源PAs代谢的调节过程,对增强幼苗抗盐性起着重要的作用。

The effects of exogenous spermidine （Spd） on the levels of polyamines （PAs） and the activities of some key enzymes involved in PA metabolism in two cucumber （Cucumis sativus L.） cultivar seedlings differing in salinity-resistance are investigated under NaCl stress in a nutrient solution culture system in this paper.The results show that the activities of agrinine decarboxylase （ADC）、ornithine decarboxylase （ODC）、S-adenosyimethionine decarboxylase （SAMDC） and polyamine oxidase （PAO） significantly increase in leaves and roots of seedlings expose to 50 mmol·L^（-1） NaCl stress,resulting in the significant increases in the contents of putrescine （Put）、Spd and spermine （Spm）.In comparison with the seedlings of lower salinity-resistant cv.Jinchun No.2,the increases of the contents of Spd and Spm and the activities of ADC,ODC and SAMDC are much higher in the seedlings of stronger salinity-resistant cv.Changchun mici,while the increases of Put content and PAO activity lower.Exogenous 0.1 mmol·L^（-1） Spd application treatment promotes rapid increases of the activities of ADC,ODC and SAMDC and significantly increases the contents of Spd and Spm,while PUt content and PAO activity decrease.The effects of exogenous Spd application are more pronounced in cv.Jinchun No.2 than in cv.Changchun mici.It indicates that exogenous Spd can be involved in the regulation of PA metabolism and play an important role in enhancing salinity stress tolerance in seedlings.