Evolution of nutrient resorption across the herbaceous genus Helianthus

Foliar nutrient resorption is a key modulator of plant nutrient use. However, evolutionary patterns for nutrient resorption remain unclear, especially in herbs. We measured nitrogen and phosphorus resorption on pre-selected leaves across the Helianthus (sunflower) genus in a common garden in Athens, GA. We analyzed our data with published leaf traits and native habitat environmental data. Using phylogenetically-controlled analyses, we tested if (1) nutrient resorption correlates with leaf economic, vasculature, and defense traits through evolutionary time, and 2) native habitat environment predicts nutrient resorption evolution. For Helianthus, nutrient resorption capacity is greater in resource-conservative species, as previously defined for Helianthus with a principle components analysis of leaf economic spectrum traits (photosynthetic rate, respiration rate, leaf lifespan, leaf mass per area, and green-leaf N and P concentration). Nutrient resorption capacity also evolutionarily corr...