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以黄瓜‘津研四号’幼苗为试材,采用Hoagland营养液栽培,研究了不同浓度(0、0.01、0.1、1和10μmol·L-1)IAA处理对50 mmol·L-1 NaHCO3胁迫下黄瓜幼苗光合特性及抗氧化系统的影响。结果表明,碱胁迫对黄瓜幼苗的生长有抑制作用,0.01~1μmol·L-1外源IAA处理可显著增加黄瓜幼苗的生物量;使叶中Na+积累降低,K+积累增加,且IAA的缓解效果具有浓度效应。叶绿素a、叶绿素b和类胡萝卜素含量提高,净光合速率(Pn)和气孔导度(Gs)增加,以1μmol·L-1 IAA处理的效果最好。添加1μmol·L-1外源IAA显著提高了碱胁迫下黄瓜叶中超氧化物歧化酶(SOD)、过氧化物酶(POD)、抗坏血酸过氧化物酶(APX)、脱氢抗坏血酸还原酶(DHAR)和谷胱甘肽还原酶(GR)的活性及还原型抗坏血酸(AsA)和谷胱甘肽(GSH)的含量,降低了碱胁迫诱导的活性氧积累和膜脂过氧化反应;而10μmol·L-1外源IAA处理则加剧碱胁迫对黄瓜幼苗的危害。
Using Hoagland nutrient solution, Cucumber ’Jinyan No.4’ seedlings were used to study the effects of IAA at different concentrations (0, 0.01, 0.1, 1 and 10 μmol·L -1) on the seedlings growth under 50 mmol·L -1 NaHCO 3 Photosynthetic Characteristics and Antioxidant System in Cucumber Seedlings. The results showed that alkaline stress had an inhibitory effect on the growth of cucumber seedlings. Exogenous IAA at the concentration of 0.01 ~ 1μmol·L -1 could significantly increase the biomass of cucumber seedling, decreased the accumulation of Na + and increased the accumulation of K +, and the alleviation effect of IAA Has a concentration effect. Chlorophyll a, chlorophyll b and carotenoid content increased, Pn and Gs increased, and IAA treatment at 1μmol·L-1 had the best effect. The addition of 1μmol·L-1 exogenous IAA significantly increased the activities of superoxide dismutase (SOD), peroxidase (POD), ascorbate peroxidase (APX) and dehydroascorbate reductase (DHAR) in cucumber leaves under alkaline stress ) And glutathione reductase (GR) and the content of ascorbate (AsA) and glutathione (GSH), and reduced the accumulation of reactive oxygen species and membrane lipid peroxidation induced by alkali stress. However, L-1 exogenous IAA exacerbated the alkali stress on cucumber seedlings.