| 摘要: |
| 海草床是近岸重要的“蓝碳”生态系统，有机负荷升高导致的硫化物胁迫是海草床衰退的重要诱因；外源铁（Fe）的添加可有效改善高有机负荷沉积物中海草的生存状态。本研究在日光温室内，通过向两种不同类型（钙质和硅质）沉积物中添加淀粉（5 g/kg）模拟海草床高有机负荷，同时添加不同量的Fe(II)（0.00、0.05、0.15、0.50 g/kg），探究了泰来草（Thalassia hemprichii）叶片光合色素（Chl a、Chl b、Cx）含量、叶绿素荧光参数（Fm、Fv/Fm、Fv/F0、ΦPSII、ETR）及抗氧化酶（POD、SOD、CAT）活性对Fe添加的响应特点。结果表明，培养过程（30 d）〖JP2〗中，两种类型的沉积物中外源Fe添加均能有效提升泰来草叶片光合色素含量、叶绿素荧光参数水平和抗氧化酶活性，且当Fe（Ⅱ）添加量为0.50 g/kg时效果最优。Fe添加量对间隙水Fe2+浓度、S2-浓度、泰来草叶片光合色素含量、叶绿素荧光参数及抗氧化酶活性均存在极显著（P<0.01）影响，底质类型对Fe2+浓度、抗氧化酶活性存在极显著（P<0.01）影响，底质类型与Fe添加量的交互作用对光合色素含量和抗氧化酶活性存在显著（P0.05）或极显著（P<0.01）影响。总体而言，Fe添加对泰来草光合作用和抗氧化酶活性的影响高于底质类型。本研究表明外源Fe能够有效改善钙质、硅质沉积物中泰来草生理生态指标。 |
| 关键词: 泰来草 外源铁 有机负荷 光合色素 叶绿素荧光 抗氧化酶 |
| DOI：10.3969/J.ISSN.2095-4972.2023.01.005 |
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| 基金项目:南方海洋科学与工程广东省实验室（广州）人才团队引进重大专项资助项目（GML2019ZD0402）；海南省高层次人才资助项目（420RC657）；教育部重点实验室专项资助项目（UCTMB202013）；海南省及海南热带海洋学院研究生创新科研资助项目（Hys2020 386，RHDYC 202120） |
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| Effects of exogenous iron on photosynthesis and antioxidant enzyme activities of Thalassia hemprichii in sediments with loadings of high organic matter |
| WANG Hui,SHI Yunfeng,WANG Shuai,CAI Jiali,LI Zhaoyang,ZHAO Muqiu,HAN Qiuying |
| (Yazhou Bay Innovation Institute, Hainan Tropical Ocean University, Sanya 572022, China;Southern Marine Science and Engineering Guangdong Laboratory, Guangzhou 511458, China;Hainan Modern Marine Ranch Engineering Research Center, Sanya 572022, China;Key Laboratory of Tropical Marine Biological Resources Utilization and Protection,Hainan Tropical Ocean University, Sanya 572022, China) |
| Abstract: |
| Seagrass meadow, an important coastal “blue carbon” ecosystem, is declining due to high input of organic matter, which could be effectively improved by addition of exogenous iron (Fe). In this study, different amounts of Fe (II) (0.00, 0.05, 0.15 and 0.50 g/kg) were added into two types(calcareous and siliceous) of sediments in greenhouse to examine the alleviating effects of Fe application on photosynthetic pigment (Chl a、Chl b、Cx), chlorophyll fluorescence parameters(Fm、Fv/Fm、Fv/F0、ΦPSII、ETR) and antioxidant enzymes (POD、SOD、CAT) of Thalassia hemprichii leaves, with starch (5 g/kg) added to simulate a high organic loading in seagrass meadow. The results showed that Fe addition in two types of sediments could both effectively improve the contents of photosynthetic pigments, the level of chlorophyll fluorescence parameters and the activity of antioxidant enzymes in a 30 day experiment and it was found that 0.50 g/kg was the most effective among all treatments. Furthermore, Fe addition had a very significant effect (P<0.01) on the contents of Fe2+ and S2- in the interstitial water of sediments, the content of photosynthetic pigment, chlorophyll fluorescence parameters and antioxidant enzyme activity of Thalassia hemprichii leaves, while the sediment type had a very significant effect on Fe2+ and antioxidant enzyme activity (P<0.01). Additionally, the interaction between sediment type and Fe addition had a significant (P<0.05) or extremely significant (P<0.05) effect on photosynthetic pigment contents and antioxidant enzyme activities. In general, the effects of Fe addition on photosynthesis and antioxidant enzyme activities were higher than those of sediment type. This study revealed that exogenous Fe could effectively improve several physiological and ecological indexes of Thalassia hemprichiigrowing in alcareous and siliceous sediments, thus it can provide data and technical support for the protection and restoration of tropical seagrass meadow. |
| Key words: marine biology Thalassia hemprichii exogenous iron organic loading photosynthetic pigments chlorophyll fluorescence antioxidant enzyme |
