Sex-specific functional traits in cycads

The Mesozoic is often referred to as the “age of cycads”. During this period, dinosaurs roamed vast cycad forests, yet modern cycads are a vestige of their Mesozoic glory. Extant species represent the oldest lineage of dioecious seed-bearing plants. This curious phylogenic position is matched by their unusual ecology: most species are extremely rare while others form dense colonies that may play important roles in forest function. In spite of this and quite remarkably, cycads are the most poorly studied lineage of seed plants and almost nothing is known of their ecophysiology. A study published in AoB PLANTS by Krieg et al. is the first of its kind to examine sex-mediated ecophysiology in cycads. Their results show unexpended differences in photosynthetic physiology and highlight the role that nitrogen-fixing soil bacteria may play in cycad reproduction and ecology. They found that species can vary markedly in nitrogen relations and that plant sex can drive unique leaf physiology. Their study is a cycadological call to arms for plant scientists to refocus efforts on this enigmatic group.