| 摘要: |
| 【目的】探明三峡库区库岸消落带植物水杉（Metasequoia glyptostroboides）的水分生理响应特性，为消落带种群构建和植物选择提供理论依据。【方法】模拟三峡库区消落带的土壤水分变化格局，以2年生水杉树苗为试材，设置对照组（C）、半淹组（HS）、全淹组（FS）以及对照 干旱组（CD）、半淹 干旱组（HSD）、全淹 干旱组（FSD）等6个不同处理，通过先后进行的水淹处理、干旱处理、恢复供水试验，研究水杉树苗在不同条件下的脯氨酸、可溶性糖、可溶性蛋白、MDA、超氧根离子（O2-·）含量及抗氧化酶（SOD、POD、ASP、CAT）活性的变化，分析前期水淹对水杉树苗后期干旱胁迫响应的影响。【结果】半淹使水杉树苗脯氨酸、可溶性糖、可溶性蛋白、丙二醛（MDA）、超氧根离子（O2-·）含量显著升高，全淹使水杉树苗脯氨酸、可溶性蛋白含量和SOD、POD活性显著升高。在干旱胁迫条件下，水杉CD与HSD组的SOD、POD活性均显著升高，而FSD组的CAT活性显著高于C组；干旱胁迫也导致3个干旱处理组的可溶性糖含量显著升高，但CD与HSD组之间脯氨酸、可溶性糖、MDA、O2-·含量和SOD、POD、CAT活性之间均无显著性差异。前期水淹并未影响水杉树苗后期对干旱胁迫响应的敏感性，恢复正常供水后，各处理组的脯氨酸含量、CAT活性都可达到对照组水平（FSD组的CAT活性除外）。【结论】水杉树苗不仅耐水湿，而且有一定的耐旱性，可以作为三峡库区消落带植被恢复重建的候选树种之一。 |
| 关键词: 水分胁迫 水杉 生理生化 消落带 三峡库区 |
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| 基金项目:重庆市基础与前沿研究计划重点项目（CSTC2013JJB00004）；中央高校基本科研业务费专项（XDJK2013A011）；国家林业公益性行业科研专项（201004039）；留学回国人员科研启动基金项目（教外司留［2010-1561］） |
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| Effects of flooding on responses of Metasequoia glyptostroboides saplings to drought |
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BAI Lin-li,HAN Wen-jiao,LI Chang-xiao
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| Abstract: |
| 【Objective】Physiological and biochemical characteristics of Metasequoia glyptostroboides saplings in response to different water stresses were studied to provide theoretical basis for species selection and population construction of the hydro-fluctuation belt of the Three Gorges Reservoir Area (TGRA).【Method】Through simulating water level changes of the hydro-fluctuation belt of the TGRA,six water treatments were applied,including the control (C),control followed by drought (CD),continuous half-submersion (HS),half submersion followed by drought (HSD),continuous full-submersion (FS) and full-submersion followed by drought (FSD).The entire experiment consisted of three phases,i.e.flooding for phase Ⅰ,drought for phase Ⅱ,and recovery for phase Ⅲ.The changes in contents of free proline,soluble sugar,soluble protein,lipid peroxidation (MDA),and O2-· as well as the activities of antioxidant enzymes (SOD,POD,ASP,and CAT) of M.glyptostroboides saplings were measured and the effects of flooding on responses of M.glyptostroboides saplings to following drought were analyzed.【Result】Contents of free proline,soluble sugar and soluble protein,MDA,and O2-· in HS were all significantly higher than those in C.Similarly,the contents of free proline and soluble protein,and activities of SOD and POD in FS were all significantly increased compared to C.When drought stress was imposed,activities of SOD and POD in CD and HSD were significantly higher than those in C,and the activity of CAT in FSD was significantly higher than that in C.Moreover,the soluble sugar content significantly increased in all the three drought stress conditions compared to C.However,no significant difference was found in contents of free proline,soluble sugar,MDA,and O2-·,and activities of SOD,POD,and CAT between CD and HSD,indicating that prior flooding had no detectable effect on subsequent sensitivity of M.glyptostroboides to drought.By the end of the recovery period,free proline content and CAT activity of the saplings under all water stresses decreased to comparable levels of C except CAT activity in FSD.【Conclusion】M.glyptostroboides saplings showed tolerance to both flooding and drought.Thus it was suggested as a candidate for the re-vegetation of the hydro-fluctuation belt of the TGRA. |
| Key words: water stress Metasequoia glyptostroboides physiology and biochemistry the hydro-fluctuation belt the Three Gorges Reservoir Area |
