Seasonal trade-offs in floral trait allocation and reproductive performance in Turnera subulata

Seasonal variation in tropical ecosystems creates contrasting environmental conditions that can influence plant reproductive strategies, however, how these conditions shape the expression of floral traits remains poorly understood. Here, we examined seasonal variation in floral size and pollen tube growth rate as a proxy for reproductive performance, and floral chemical profiles in Turnera subulata Sm. (Passifloraceae) in the lowland tropics of Panama. Flowers were smaller during the wet season, and although pollen tube growth rate did not differ directly between seasons, it increased with floral size. Floral compounds were dominated by long-chain hydrocarbons, and seasonal differences were mainly quantitative rather than qualitative. Total amount of floral compounds was higher in the dry season and declined with increasing floral size. Our results suggest that seasonal variation may influence how resources are allocated among floral growth, reproductive performance, and chemistry in T. subulata. Allocation trade-offs among floral traits may therefore help explain variation in reproductive strategies across seasonal tropical environments.