Sun-shade variation in bamboo (Poaceae: Bambusoideae) leaves

Abstract

The differential occurrence of fusoid cells in sun compared to shade leaves of three species of bamboo (Poaceae: Bambusoideae) was examined through leaf morphology and anatomy. Leaves grown in sun were consistently smaller and thicker and lacked fusoid cells, whereas leaves grown in shade were consistently larger, thinner, and had fusoid cells. These differences were also found between exterior and interior leaves within one individual of one of these three species. An infusion experiment using a fourth species indicated that light transmission increased dramatically as fusoid cells (or the spaces formed by their collapse) absorbed mineral oil. We propose that fusoid cells are a mechanism to trap and redistribute light more efficiently in shade leaves of bamboo and early-diverging grasses. This is the first report of leaf anatomical sunshade variation in bamboo leaves, but we emphasize the preliminary nature of our observations and the need for further study. © 2011 Royal Botanic Gardens and Domain Trust.