Reproductive biology of Talisia esculenta (Cambess.) Radlk. (Sapindaceae)

The family Sapindaceae comprises species with different reproductive strategies and sexual systems; however, dioecy is rarer and has been little investigated in tree species. We analyzed the reproductive biology of Talisia esculenta (Cambess.) Radlk. to understand its sexual system and reproductive potential. For this purpose, we examined floral biology and the reproductive system in natural populations of T. esculenta. The species exhibits two sexual morphs: individuals with morphologically hermaphroditic but functionally pistillate flowers, characterized as female, and individuals with staminate flowers, characterized as male. The hermaphroditic flowers produce viable pollen but do not self-pollinate due to strong hercogamy and the permanent indehiscence of the anthers; therefore, they are functionally female. These characteristics classify T. esculenta as an allogamous and androdioecious species, specifically a functionally dioecious type. Natural and hand pollination between male and female individuals resulted in a higher percentage of fruit set with significantly superior quality compared to fruits from hand cross-pollination between female individuals. However, the fruit set rate in these crosses was only 25% of the floral investment. The species is an obligatory xenogamous and invests in a high floral display (75% of the flowers) to attract pollinators. This is a secondary sexual trait that favors pollination. Pollination tests indicate that local pollinators are effective, suggesting that other factors may influence the low natural fruit set rate. Genetic and phylogenetic studies are necessary to further understand androdioecy and the reproductive behavior of T. esculenta.