Pronin Eugeniusz, Banaś Krzysztof, Chmara Rafał, Ronowski Rafał, Merdalski Marek, Santoni Anne-Lise, Mathieu Olivier
Department of Plant Ecology, Faculty of Biology, University of Gdansk, 80-309 Gdansk, Poland.
Biogéosciences, UMR 6282 CNRS, Université Bourgogne Franche-Comté, F-21000 Dijon, France.
Plants (Basel). 2024 Sep 9;13(17):2529. doi: 10.3390/plants13172529.
Most of the aquatic vegetation produces organic substances via the C3 photosynthetic pathway (mosses, isoetids- L., (L.) Raf., and vascular plants) or Crassulacean acid metabolism (CAM, e.g., (L.) Asch. and L.) or by their ability to use HCO via carbon concentration mechanisms (CCMs-some elodeids and charophytes). Differentiating these predominant photosynthetic pathways in aquatic vegetation based on their organic matter (OM) carbon stable isotopes (C) is a complex task, in contrast to terrestrial plants. This study investigates the OM deposition, characterized by C values in 10 macrophyte species with different photosynthetic pathways (C3, CAM, and CCM) collected from 14 softwater Lobelia lakes in northern Poland. The higher C values distinguish the CCM group, indicating their use of C-enriched HCO¯ in photosynthesis. CAM species show slightly higher C values than C3, particularly in lower pH lakes. Principal component analysis of isotopic and environmental data did not yield clear distinctions by the groups, but still, they significantly differ in light of analyzed parameters and isotopic signals (PRMANOVA = 5.08, < 0.01; K-W H = 27.01, < 0.001). The first two PCA dimensions showed that the water pH and Ca concentration positively influenced C values. The influence of light conditions on C values revealed by third PCA components seems to also be important. In summary, northern Polish Lobelia lakes serve as a key differentiation point between vegetation employing CCMs and those relying on C3/CAM photosynthesis without HCO utilization, providing insights into transitions in plant communities within these ecosystems.
大多数水生植被通过C3光合途径（苔藓、水韭科植物、轮藻和维管植物）或景天酸代谢（CAM，例如，狸藻和苦草）或通过其利用碳浓缩机制（CCM——一些伊乐藻属植物和轮藻）利用HCO₃⁻的能力来产生有机物质。与陆生植物相比，基于水生植被的有机物质（OM）碳稳定同位素（δ¹³C）来区分这些主要的光合途径是一项复杂的任务。本研究调查了从波兰北部14个软水半边莲湖泊中采集的10种具有不同光合途径（C3、CAM和CCM）的大型植物物种中以δ¹³C值为特征的OM沉积情况。较高的δ¹³C值区分了CCM组，表明它们在光合作用中使用了富含¹³C的HCO₃⁻。CAM物种的δ¹³C值略高于C3物种，特别是在较低pH值的湖泊中。对同位素和环境数据进行主成分分析并没有按组产生明确的区分，但尽管如此，根据分析参数和同位素信号，它们仍存在显著差异（PRMANOVA = 5.08，P < 0.01；K-W H = 27.01，P < 0.001）。前两个主成分分析维度表明，水的pH值和钙浓度对δ¹³C值有正向影响。第三个主成分分析成分揭示的光照条件对δ¹³C值的影响似乎也很重要。总之，波兰北部的半边莲湖泊是采用CCM的植被与依赖C3/CAM光合作用而不利用HCO₃⁻的植被之间的关键区分点，为这些生态系统内植物群落的转变提供了见解。
