Endemic Cyclamen purpurascens Subsp. immaculatum: Linking Habitat Conditions to PSII Efficiency and Reproductive Output

Information on factors influencing fitness, flowering, and fruit production in Cyclamen species remains limited. This study evaluated these traits throughout the growing season in three populations of Cyclamen purpurascens subsp. immaculatum under contrasting environments: a young beech forest (half-shade), an old beech forest (shade), and an open meadow. Because this protected endemic taxon of the Western Carpathians (Veľká Fatra and Starohorské vrchy Mountains, Slovakia) cannot be sampled destructively, we used in situ observations and chlorophyll a fluorescence measurements. We found seasonal variation in photosystem II (PSII) efficiency and high environmentally driven inter-individual variability. Plants in the meadow exhibited significantly lower values of Fv/Fm, Fm/F0, and Area parameters, likely reflecting combined microclimatic stress. These plants also produced significantly fewer flowers, suggesting reduced resource availability for reproduction. In contrast, no significant differences in fluorescence parameters were detected between the two forest habitats, which showed similar seasonal dynamics. However, plants in the young forest produced the most flowers and slightly more fruits than those in the old forest or open meadow. Overall, our results suggest that meadow habitats may be less suitable for this taxon, while old-forest environments are tolerated but may reduce reproductive output. Semi-shaded forest habitats may be important for long-term persistence of this taxon.