Effects of Flowering Time and Temperature on Growth and Reproduction in Leontodon autumnalis var. taraxaci, a Late-flowering Alpine Plant

Abstract

In most alpine and arctic plants there is selection for early flowering because of the short time available to complete seed production before the season terminates. Despite this, some species initiate flowering late in the season, but little work has been done on the reproductive ecology of such species. This work investigates the reproductive consequences of late flowering in Leontodon autumnalis var. taraxaci in alpine southwest Norway during two seasons. In addition, the effects of an experimental increase in growing-season temperature on growth and reproduction are also examined. The reproductive success of Leontodon decreased strongly as the flowering season progressed, possibly as a result of increased climatic severity and increased extent of pollen and resource limitation on reproduction. Experimentally warmed plants produced significantly more and heavier seeds, and flowered more than 1 wk earlier than control plants, showing that temperature conditions influence both reproductive processes and flowering phenology. The results suggest that this late-flowering alpine species will bloom earlier, reproduce more, and grow larger under global warming.