| 摘要: |
| 【目的】明确适宜浓度褪黑素（melatonin）对小麦幼苗的抗旱生理效应，为旱地小麦高产提供依据。【方法】用PEG-6000模拟干旱，选用抗旱性不同的小麦品种济麦22（抗旱性一般）和衡观35（抗旱品种）为试材，设置对照（CK）、20% PEG（PEG）、20% PEG+10 μmol/L褪黑素（T-10）、20% PEG+100 μmol/L褪黑素（T-100）、20% PEG+300 μmol/L褪黑素（T-300）5个处理，研究褪黑素对小麦种子发芽和形态的影响，选择有明显改善PEG胁迫的褪黑素浓度，研究褪黑素对小麦幼苗的抗旱调控作用。【结果】T-100和T-300均不同程度地改善了PEG胁迫下小麦种子的发芽指标和种子形态，尤其T-300可显著提高PEG胁迫下两个小麦品种的发芽势、发芽率、幼苗干质量，使其迅速恢复至对照水平；显著提高胚根长、胚芽长、幼苗含水量，但未恢复至对照水平。T-10对干旱胁迫小麦发芽状况无显著改善。T-300显著增加干旱胁迫下两个小麦品种幼苗的净光合速率，显著增加济麦22的蒸腾速率和衡观35的瞬时水分利用效率、Fm′，降低了衡观35的Fo。衡观 35的蒸腾速率明显低于济麦22，而水分利用效率明显高于济麦22。 T-300显著降低了干旱胁迫下济麦22的MDA含量、POD活性、可溶性糖含量，而显著增强其SOD活性、可溶性蛋白含量、脯氨酸含量和根系活力。衡观35本身抗旱性强，干旱胁迫下的MDA含量未升高，POD活性低于济麦22；施加褪黑素后SOD活性、根系活力显著增加，可溶性糖含量增至对照水平。【结论】300 μmol/L 褪黑素可明显改善PEG干旱胁迫下的小麦发芽状况，是改善干旱胁迫下小麦萌发的有效浓度。衡观35在褪黑素调节下抗旱恢复能力强于济麦22。 |
| 关键词: 褪黑素 干旱胁迫 小麦发芽 抗旱生理 |
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| 基金项目:国家现代农业产业技术体系项目(CARS-03-05)；国家重点研发计划项目(2017YFD0300909)；河北省教育厅科学研究计划项目(QN2019046)；河北省自然科学基金项目(C2019204358)；保定市科技计划项目(1911ZN010) |
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| Effect of exogenous melatonin on seed germination and leaf physiological characteristic of wheat seedling under drought stress |
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LI Hongye,ZHAI Xiuzhen,ZHANG Shaocong,et al
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| Abstract: |
| 【Objective】This study investigated the physiological effect of melatonin with suitable concentrations on wheat seedling to provide basis for improving wheat production in drought region.【Method】A phytotron experiment was conducted to study the germination and seedling drought-resisting physiology in different wheat varieties (Jimai 22 and Hengguan 35) with melatonin.Five treatments were set including control (CK),20% polyethylene glycol (PEG),20% PEG+10 μmol/L melatonin (T-10),20% PEG+100 μmol/L melatonin (T-100) and 20% PEG+300 μmol/L melatonin (T-300).【Result】T-100 and T-300 improved germination indexes and seed morphology at different levels.Particularly,T-300 treatment ameliorated inhibiting effects of PEG on germination potential,germination efficiency and seed dry weight of two wheat varieties and they returned to same level of CK.It also significantly increased lengths of coleoptile and radicles under PEG stress,but not to the CK level.T-10 had no effect on wheat seed germination under PEG.T-300 treatment significantly increased net photosynthetic rate (Pn) of the two wheat varieties,significantly increased transpiration rate (Tr) of Jimai 22,increased instantaneous water use efficiency and Fm′,while decreased Fo of Hengguan 35.Hengguan 35 had significantly lower Tr and higher water use efficiency in comparison to Jimai 22.T-300 significantly decreased MDA content,POD activity and soluble sugar content,but increased SOD activity,soluble protein content,proline content and root vigor of Jimai 22 under drought condition.Hengguan 35 with high drought resistant could keep stable MDA content under drought condition but POD activity was lower than that of Jimai 22.After applying melatonin,SOD activity and root vigor were increased significantly,and soluble sugar content recovered to the CK level.【Conclusion】 Melatonin at 300 μmol/L concentration was effective for improving seed germination under drought condition.The drought resistance of Hengguan 35 with melatonin application was higher than that of Jimai 22. |
| Key words: melatonin drought stress wheat germination drought resisting physiology |
