Effects of Environmental Conditions on the Individual Architectures and Photosynthetic Performances of Three Species in Drosera

The aim of this study was to determine the environmental conditions, individual architectures, and photosynthetic efficiencies of three sundew species: Drosera rotundifolia, D. anglica, and D. intermedia, found in well-preserved peatlands and sandy lake shores in NW Poland. Morphological traits and chlorophyll a fluorescence (Fv/Fm) were measured in 581 individuals of Drosera. D. anglica occupies the best-lit and warmest habitats, and also those that are the most heavily hydrated and the richest in organic matter; its rosettes are larger under conditions of higher pH, less organic matter, and less well-lit habitats. D. intermedia occupies substrates with the highest pH but the lowest conductivity, the poorest level of organic matter, and the least hydration. It is highly variable in terms of individual architecture. D. rotundifolia occupies habitats that are the most diverse, and that are often poorly lit, with the lowest pH but the highest conductivity. It is the least variable in terms of individual architecture. The value of the Fv/Fm ratio in Drosera is low (0.616 ± 0.137). The highest photosynthetic efficiency is achieved by D. rotundifolia (0.677 ± 0.111). It is significant for all substrates, indicating its high phenotypic plasticity. The other species have lower and similar Fv/Fm values (D. intermedia, 0.571 ± 0.118; D. anglica, 0.543 ± 0.154). Due to its very low photosynthetic efficiency, D. anglica avoids competition by occupying highly hydrated habitats. D. intermedia has adapted to the occupation of highly variable habitats in terms of hydration, while D. rotundifolia is primarily adapted to variable light conditions.