Calcium-Dependent Lamina Production ofNymphoides peltata(Gmel.) O. Kuntze (Menyanthaceae): Implications for Distribution

Abstract

Nymphoides peltata (Gmel.) O. Kuntze, a nymphaeid macrophyte, occurs commonly in polder and fluviatile areas in large parts of Europe and Asia. In contrast to the nymphaeid macrophytes Nymphaea alba L. and Nuphar lutea (L.) Sm., Nymphoides peltata is almost completely absent from poorly-buffered waters and is never found in acid water bodies. Transplantation experiments in water bodies of varying alkalinity demonstrated that, irrespective of the sediment type, leaf production of Nymphoides did occur in poorly-buffered waters, but not in acid waters. Cultivation experiments showed that floating leaf development of Nymphoides peltata could only take place if sufficient calcium was available in the water layer or in twice-demineralized water. Addition of calcium to an acid cultivation medium or to water collected from an acid moorland pool resulted in leaf production. Growth of Nymphoides in acid waters is impossible due to insufficient calcium concentrations in the water layer of such waters. It is suggested that the absence of Nymphoides peltata in some poorly-buffered water bodies is partly due to the spatial isolation from rivers and canals and the high frequence of desiccation. The restricted occurrence of Nymphoides peltata to well-buffered alkaline waters is functionally more related to the calcium availability than to the bicarbonate content.