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| 太湖两种大型沉水植物无机碳利用效率差异及其机理 | |
| 引用本文： | 肖月娥,陈开宁,戴新宾,许晓明. 太湖两种大型沉水植物无机碳利用效率差异及其机理[J]. 植物生态学报, 2007, 31(3): 490-496. DOI: 10.17521/cjpe.2007.0061 |
| 作者姓名： | 肖月娥 陈开宁 戴新宾 许晓明 |
| 作者单位： | 1 南京农业大学生命科学学院植物科学系, 南京 210095 2 中国科学院南京地理湖泊研究所, 南京 210008 |
| 基金项目： | 国家重点基础研究发展计划(973计划);国家高技术研究发展计划(863计划) |
| 摘 要： | 该文通过pH值漂移实验比较了太湖常见的两种沉水植物菹草(Potamogeton crispus)和马来眼子菜(P. malaianus)对无机碳利用效率的差异,并测定两者无机碳吸收关键酶——碳酸酐酶的活性,探讨了两者无机碳吸收效率差异的原因。根据太湖自然水体的无机碳条件设定了3种不同碱度条件,测定起点pH值和无机碳条件。不同碱度下pH值漂移变化和总无机碳/碱度比值的结果表明,两个种均能利用${HCO_{3}}^{-}$,适应低无机碳条件。两者对${HCO_{3}}^{-}$的吸收速率决定于其浓度大小,该离子浓度越大,光合速率越高。但是对${HCO_{3}}^{-}$的吸收速率存在差异:马来眼子菜在各碱度下终点pH值显著高于菹草,整体光合速率较高。CO2-光合速率响应曲线表明,在高pH值(CO2受到限制)时,马来眼子菜对CO2亲和力较大。尽管菹草在pH值较低(6.5~7.0)时有相对较高的光合速率,但是基于太湖自然水体夏季高pH值(>8.5)条件,马来眼子菜具有更大的生长优势,成为优势种群。两者无机碳吸收速率的差异是造成它们生活史差异和时间生态位的一重要原因。同时,马来眼子菜碳酸酐酶活性明显高于菹草,表明在相同无机碳条件下,前者催化${HCO_{3}}^{-}$与CO2之间的转化效率更高,这可能是造成两者无机碳吸收速率差异的原因。 |
| 关 键 词： | 沉水植物 无机碳 光合速率 碳酸酐酶 种群演替 |
| 收稿时间： | 2006-03-24 |
| 修稿时间： | 2006-03-24 |
DISSOLVED INORGANIC CARBON UPTAKE IN TWO SUBMERGED MACROPHYTES FROM TAIHU LAKE CHINA |
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| XIAO Yue-E,CHEN Kai-Ning,DAI Xin-Bin,XU Xiao-Ming. DISSOLVED INORGANIC CARBON UPTAKE IN TWO SUBMERGED MACROPHYTES FROM TAIHU LAKE CHINA[J]. Acta Phytoecologica Sinica, 2007, 31(3): 490-496. DOI: 10.17521/cjpe.2007.0061 | |
| Authors: | XIAO Yue-E CHEN Kai-Ning DAI Xin-Bin XU Xiao-Ming |
| Affiliation: | Department of Plant Sciences, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China Nanjing Institute of Geography & Limnology, Chinese Academy of Sciences, Nanjing 210008, China |
| Abstract: | Aims The difference in efficiency and mechanism of absorption of dissolved inorganic carbon (DIC) by two common species in Taihu Lake, Potamogeton crispus and P. malaianus, has rarely been studied. We ask: 1) do the two species differ in DIC absorption efficiency, and 2) what are the implications of any difference, especially in terms of succession in summer?Methods We used a pH drift experiment to assess abilities of the two species to use DIC. Matching the natural inorganic carbon in Taihu Lake, we used three different alkalinities (1 200, 1 600, and 2 000 μmol·L-1), pH values and ${HCO_{3}}^{-}$ concentrations at the beginning of the experiments. Simultaneously, we measured the activity of carbonic anhydrase of both species.Important findings Both species can utilize ${HCO_{3}}^{-}$ and adapt to low inorganic carbon conditions. Both species used ${HCO_{3}}^{-}$ more efficiently at high alkalinity, so the efficiency of ${HCO_{3}}^{-}$ use depends on the concentration of this ion. However, different efficiencies in the use of ${HCO_{3}}^{-}$ were evident in terms of the photosynthetic rates and pH values attained at the end of the experiments. Photosynthesis rates and pH values of P. malaianus were higher than those of P. crispus at all alkalinities. Photosynthetic rates-CO2 curves of the two species showed that P. malaianus uses CO2 more efficiently than P. crispus when the pH value of water is higher, i.e., when the concentration of CO2 is low. Furthermore, the carbonic anhydrase activity of P. malaianus was distinctly higher than that of P. crispus. This result showed P. malaianus could transfer ${HCO_{3}}^{-}$ to CO2 more quickly than P. crispus, which was correlated with the different efficiencies of use of inorganic carbon. This study suggests the pH of Taihu Lake in summer may be advantageous to the colonization of P. malaianus, compared to P. crispus. Furthermore, the different efficiencies correlate with the successional patterns of the two submerged macrophytes. |
| Keywords: | submerged macrophyte dissolved inorganic carbon photosynthetic rate carbonic anhydrase population succession |
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