Sex change in the subdioecious shrub Eurya japonica (Pentaphylacaceae)

• Published in: Ecology and evolution Vol. 7; no. 7; pp. 2340 - 2345
• Main Authors: Wang, Hui, Matsushita, Michinari, Tomaru, Nobuhiro, Nakagawa, Michiko
• Format: Journal Article
• Language: English
• Published: England John Wiley & Sons, Inc 01-04-2017; John Wiley and Sons Inc
• Subjects: Abiotic factors; Environmental factors; Eurya japonica; Females; Fitness; Flowers & plants; Gender differences; Growth rate; Hermaphrodites; internal physiological condition; Light; Males; Original Research; Physiological effects; Physiology; Plant populations; Population; Reproductive fitness; Sex; sex expression; Sex ratio; steady state; subdioecy; China; Japan; steady state; sex expression; internal physiological condition; subdioecy; sex ratio
• ISSN: 2045-7758; 2045-7758
• DOI: 10.1002/ece3.2745

Sex change affects the sex ratios of plant populations and may play an essential role in the evolutionary shift of sexual systems. Sex change can be a strategy for increasing fitness over the lifetime of a plant, and plant size, environmental factors, and growth rate may affect sex change. We described frequent, repeated sex changes following various patterns in a subdioecious Eurya japonica population over five successive years. Of the individuals, 27.5% changed their sex at least once, and these changes were unidirectional or bidirectional. The sex ratio (females/males/all hermaphrodite types) did not fluctuate over the 5 years. In our study plots, although the current sex ratio among the sexes appears to be stable, the change in sex ratio may be slowly progressing toward increasing females and decreasing males. Sex was more likely to change with higher growth rates and more exposure to light throughout the year. Among individuals that changed sex, those that were less exposed to light in the leafy season and had less diameter growth tended to shift from hermaphrodite to a single sex. Therefore, sex change in E. japonica seemed to be explained by a response to the internal physiological condition of an individual mediated by intrinsic and abiotic environmental factors.
Subdioecious Eurya japonica had diverse patterns of sex change. The sex ratio did not fluctuate over the 5 years, whereas the estimated transition probability matrix and steady state suggest increasing female and decreasing male individuals over a longer timescale. Internal condition was suggested to correlate with the occurrence and pattern of sex change. Therefore, sex change in E. japonica seemed to be explained by a response to the internal physiological condition of an individual mediated by intrinsic and abiotic environmental factors.