School of Ecology and Environmental Sciences, Yunnan University & Yunnan Key Laboratory for Plateau Mountain Ecology and Restoration of Degraded Environments, Kunming 650091, Yunnan, China; International Cooperative Center of Plateau Lake Ecological Restoration and Watershed Management of Yunnan, Kunming 650091, Yunnan, China.
Institute of International Rivers and Eco-security, Yunnan Key Laboratory of International Rivers and Trans-Boundary Eco-security, Yunnan University, Kunming, 650091, China.
Water Res. 2024 Dec 1;267:122468. doi: 10.1016/j.watres.2024.122468. Epub 2024 Sep 17.
The state transition theory suggests that the decline of submerged macrophytes in shallow lakes is closely associated with reduced stoichiometric homeostasis, particularly phosphorus homeostasis (H). The degradation typically progresses from deeper to shallower regions, indicating a potential positive correlation between the deepwater adaptability (DA) and H values of submerged macrophytes. Here, we investigated the distribution pattern of submerged macrophytes across different water depths of Erhai Lake to test this hypothesis. The results revealed a significant positive correlation between the DA and H values of submerged macrophytes. Allometric analysis indicated that the morphological plasticity of submerged macrophytes was linked to their H. Species with higher H values, like Potamogeton maackianus, had robust plasticity strategies, particularly "real plasticity", that enabled them to cope with deeper water stress. In contrast, species with lower H values (Ceratophyllum demersum and Hydrilla verticillata) experienced nutrient declines, which hindered their adaptation. Additionally, species with higher H values exhibited closer connections within the plant traits-environment network, indicating that their morphological plasticity adjustments allow better adaptation to the environmental changes caused by increasing water depth. These results confirm the relationship between DA and H in submerged macrophytes and explain the mechanisms underlying the correlation, thus expanding regime shift theory.
状态转换理论表明，浅水湖泊中沉水植物的衰退与化学计量内稳性降低密切相关，特别是磷内稳性（H）。退化通常从较深的区域向较浅的区域发展，这表明沉水植物的深水适应性（DA）和 H 值之间可能存在正相关关系。在这里，我们研究了洱海不同水深的沉水植物分布模式，以检验这一假设。结果表明，沉水植物的 DA 和 H 值之间存在显著的正相关关系。异速生长分析表明，沉水植物的形态可塑性与其 H 值有关。H 值较高的物种，如马来眼子菜，具有较强的可塑性策略，特别是“真实可塑性”，使其能够应对更深的水胁迫。相比之下，H 值较低的物种（菹草和黑藻）经历了养分下降，这阻碍了它们的适应。此外，H 值较高的物种在植物特征-环境网络中表现出更紧密的联系，这表明它们的形态可塑性调整使它们能够更好地适应由于水深增加而引起的环境变化。这些结果证实了沉水植物中 DA 和 H 之间的关系，并解释了相关的机制，从而扩展了状态转换理论。
