Sex-specific outcrossing advantages and sexual dimorphism in the
seedlings of dioecious trees
Abstract
Dioecious trees are important components of many forest ecosystems.
Outcrossing advantage and sexual dimorphism are two major mechanisms
that explain the persistence of dioecious plants; however, they have
rarely been studied in dioecious trees. In this study, we investigated
the influence of gender and genetic distance between parental trees
(GDPT) on the growth and functional traits of 229 seedlings of a
dioecious tree, Diospyros morrisiana. We found significant positive
relationships between GDPT and seedling sizes and tissue density.
However, the positive outcrossing effects on seedling growth mainly
manifested in female seedlings, but were not prominent in male
seedlings. Male seedlings generally had higher biomass and leaf area
than female seedlings, but such differences diminished as the GDPT
increased. Our research highlights that outcrossing advantage in plants
can be sex-specific and sexual dimorphism begins from the seedling stage
of dioecious trees.