Evidence of sex change inIlex integra

Abstract

Sex change has been recognised in some plants. The sex change in dioecious woody plants includes a monoecious state, which means that the timing of the change is synchronous in branches or shoots but not synchronous among plants, such as in partial dioecious woody plants. To determine whether such a phenomenon is common in woody plants, we investigated the sex expression in two populations of the bird-dispersed, dioecious woody plant Ilex integra Thunb. (Aquifoliaceae), one of the climax forest species in East Asia, over 3 years. No monoecious trees or hermaphrodite flowers were observed. Sex changes were observed at low frequencies, i.e., both female to male and male to female. This study suggests that I. integra may be a complete dioecious woody plant species and that the sex change occurs at the individual level, indicating that the timing of sex change is synchronous in an individual tree.