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以‘新泰密刺’和‘津优1号’黄瓜种子为试材,采用培养皿发芽方式,研究了添加纯化腐植酸PHA(添加浓度0、25、50、100、150mg·L~(-1))对NO_3~-胁迫下(75mmol·L~(-1))黄瓜种子萌发及幼芽抗氧化物酶活性的影响。结果表明:NO_3~-胁迫使黄瓜种子发芽率、主根长、侧根长、侧根数、下胚轴长度和粗度以及幼芽鲜质量明显减少;添加PHA处理使2个黄瓜品种的上述项目值都明显增加,表明部分缓解了NO_3~-胁迫。黄瓜种子发芽过程中,由于NO_3~-胁迫,幼芽的电解质渗漏率显著增加、子叶中α-淀粉酶活力下降、胚根脱氢酶活力增加;胚根和胚轴中丙二醛(MDA)及可溶性蛋白质含量、超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性均增加。添加PHA后,幼芽的电解质渗漏率显著减小,随PHA浓度的增加,减小的差值变小;子叶中α-淀粉酶活性和胚根脱氢酶活性增加,添加PHA浓度高时呈下降趋势;胚根和胚轴中MDA含量减少,添加PHA浓度高时又有增加趋势;可溶性蛋白质含量增加,添加PHA浓度高时显示下降趋势;SOD、POD、CAT活性均呈下降趋势。黄瓜种子发芽受到NO_3~-胁迫时,都因PHA的添加而表现出不同程度对NO_3~-胁迫的正向缓解,使幼芽趋于正常。黄瓜种子发芽在NO_3~-胁迫添加PHA后的生理生化指标的变化也表现出品种和器官不同的感受性差异。该试验表明,以PHA添加100mg·L~(-1)处理对胁迫NO_3~-下黄瓜种子效果较佳。
The seedlings of ’Xintiamilian’ and ’Jinyou No.1’ cucumber seeds were used as materials to study the effects of adding humic acid PHA (0, 25, 50, 100, 150 mg · L ~ 1) on seed germination and antioxidant enzyme activity of cucumber seedlings under NO_3 ~ - stress (75 mmol·L -1). The results showed that the germination rate, main root length, lateral root length, lateral root number, hypocotyl length and thickness as well as the fresh weight of cucumber seedlings decreased significantly under the NO_3 ~ - stress treatment. Adding PHA to the two cucumber cultivars Significantly increased, indicating that part of the mitigation of NO_3 ~ - stress. In the process of cucumber seed germination, the leakage rate of electrolyte in shoots increased significantly due to NO_3 ~ - stress, the activity of α-amylase in cotyledons decreased and the activity of radicle dehydrogenase increased. The content of malondialdehyde (MDA) in radicle and hypocotyls ) And soluble protein content, superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) activity increased. When PHA was added, the leakage rate of electrolyte in shoots was significantly reduced, and the difference of decrease was smaller with the increase of PHA concentration; α-amylase activity and radicle dehydrogenase activity in cotyledons increased. When PHA concentration was high (P <0.05). The content of MDA decreased in radicle and hypocotyls and increased with the increase of PHA concentration. The content of soluble protein increased with the increase of PHA concentration. The activity of SOD, POD and CAT showed a decreasing trend. The seed germination of cucumber was affected by NO_3 ~ - stress, and all of them showed positive alleviation of NO_3 ~ - stress to varying degrees due to the addition of PHA, and the buds tended to be normal. The changes of physiological and biochemical indexes of cucumber seed germination after adding PHA under NO_3 ~ - stress also showed different sensibility differences among varieties and organs. The results showed that adding 100 mg · L -1 PHA to the cucumber seedlings under stress NO_3 ~ - was better.