J Integr Plant Biol ›› 2009, Vol. 51 ›› Issue (6): 604-613.DOI: 10.1111/j.1744-7909.2009.00827.x

Special Issue: Ecology and Global Changes

• Molecular Ecology and Evolution • Previous Articles     Next Articles

Neither Biased Sex Ratio nor Spatial Segregation of the Sexes in the Subtropical Dioecious Tree Eurycorymbus cavaleriei (Sapindaceae)

Puxin Gao1,4, Ming Kang2,3, Jing Wang2,3, Qigang Ye1 and Hongwen Huang1,2,3*   

  1. 1 Wuhan Botanical Garden, the Chinese Academy of Sciences, Wuhan 430074, China
    2 Key Laboratory of Plant Resources Conservation and Sustainable Utilization, the Chinese Academy of Sciences, Guangzhou 510650, China
    3 South China Botanical Garden, the Chinese Academy of Sciences, Guangzhou 510650, China
    4 Lushan Botanical Garden, Jiangxi Province and the Chinese Academy of Sciences, Lushan 332900, China
  • Received:2008-07-27 Accepted:2009-03-05 Published:2009-06-08
  • About author: *Author for correspondence Tel: +86 20 3725 2778; Fax: +86 20 3725 2771; E-mail: huanghw@mail.scbg.ac.cn

Abstract:

Knowledge of sex ratio and spatial distribution of males and females of dioecious species is both of evolutionary interest and of crucial importance for biological conservation. Eurycorymbus cavaleriei, the only species in the genus Eurycorymbus (Sapindaceae), is a dioecious tree endemic to subtropical montane forest in South China. Sex ratios were investigated in 15 natural populations for the two defined ages (young and old). Spatial distribution of males and females was further studied in six large populations occurring in different habitats (fragmented and continuous). The study revealed a slight trend of male-biased sex ratio in both ages of E. cavaleriei, but sex ratio of most populations (13 out of 15) did not display statistically significant deviation from equality. All of the four significantly male-biased populations in the young class shifted to equality or even female-biased. The Ripley's K analysis of the distribution of males with respect to females suggested that individuals of the opposite sexes were more randomly distributed rather than spatially structured. These results suggest that the male-biased sex ratio in E. cavaleriei may result from the precocity of males and habitat heterogeneity. The sex ratio and the sex spatial distribution pattern are unlikely to constitute a serious threat to the survival of the species.

Gao P, Kang M, Wang J, Ye Q, Huang H (2009). Neither biased sex ratio nor spatial segregation of the sexes in the subtropical dioecious tree Eurycorymbus cavaleriei (Sapindaceae). J. Integr. Plant Biol. 51(6), 604–613.

Key words: dioecy, Eurycorymbus cavaleriei, rare species, sex ratio, spatial segregation of the sexes

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