Different mechanisms of bicarbonate use affect carbon isotope composition in Ottelia guayangensis and Vallisneria denseserrulata in a karst stream
Different mechanisms of bicarbonate use affect carbon isotope composition in Ottelia guayangensis and Vallisneria denseserrulata in a karst stream
复制标题
碳酸氢盐使用的不同机制影响喀斯特溪流中的Ottelia guayangensis和Vallisneria denserrulata的碳同位素组成
DOI：
10.1016/j.aquabot.2020.103310
复制
发表时间：
2021-01-01
期刊：
影响因子：
1.8
通讯作者：
Li, Wei
中科院分区：
文献类型：
--
作者：
Jiang, Hong Sheng;Jin, Quan;Li, Wei
与陆生植物相比，大型植物生活在极其不同的碳环境中。为了应对自然水生系统中碳酸氢盐占主导地位的无机碳，许多大型植物已经开发了HCO 3-利用的能力，以减轻水生系统中CO2的限制。在本研究中，所有目前在岩溶流中的水生植物进行了调查，我们发现，7的9种能够使用HCO 3-和两种在岩溶流的源被限制到CO2的使用。两种不同的抑制剂被用来确定HCO 3的使用机制，在观阳海葵和苦草denseserrulata，唯一的物种共存，从上游到下游。O. guanyangensis，然后是O. Guanyangensis向下游CAext和阴离子交换（AE）介导的HCO 3利用的联合机制转变。在这两个物种中，高浓度的HCO 3-诱导的能力，利用HCO 3-，但高浓度的CO2抑制这种能力。从上游到下游，CO2的减少导致HCO 3-的使用比例增加，从而导致O. guanyangensis。然而，一个恒定的CAext和AE介导的HCO 3-的使用导致一个相对稳定的三角洲C-13在密齿瓦兰从河源到330米，然后增加的比例HCO 3-的使用在流出口与三角洲C-13的变化。
Macrophytes live in extremely different carbon environments compared to terrestrial plants. In response to bicarbonate dominated inorganic carbon in natural aquatic systems, the ability for HCO3- use has been developed in many macrophytes to alleviate a limitation by CO2 in aquatic systems. In the present study, all present macrophytes in a karst stream were investigated, and we found that seven of nine species were able to use HCO3- and two species at the source of the karst stream were restricted to CO2 use. Two different inhibitors were used to determine the HCO3- use mechanisms in Ottelia guanyangensis and Vallisneria denseserrulata, the only species coexisting from up- to down-stream. External carbonic anhydrase (CAext) mediated HCO3- use was present in O. guanyangensis up-stream, and then O. guanyangensis shifted to a combined mechanism of CAext and anion exchange (AE) mediated HCO3- use down-stream. In these two species, high HCO3- concentration induced the ability to use HCO3-, but high CO2 concentration inhibited this ability. From up-stream to down-stream, the decreasing CO2 induced increasing proportion of HCO3- use that led to changes in the delta C-13 in O. guanyangensis. However, a constant CAext and AE mediated HCO3- use caused a relatively stable delta C-13 in V. denseserrulata from river source to 330 m and then increased the proportion of HCO3- use at the stream outlet associated with the change in delta C-13.