Department of Biology, Trent University, Peterborough, ON, Canada.
Department of Integrative Biology, University of Guelph, Guelph, ON, Canada.
J Evol Biol. 2018 Sep;31(9):1405-1412. doi: 10.1111/jeb.13335. Epub 2018 Jul 4.
Most dioecious plants are perennial and subject to trade-offs between sexual reproduction and vegetative performance. However, these broader life-history trade-offs have not usually been incorporated into theoretical analyses of the evolution of separate sexes. One such analysis has indicated that hermaphroditism is favoured over unisexuality when female and male sex functions involve the allocation of nonoverlapping types of resources to each sex function (e.g. allocations of carbon to female function vs. allocations of nitrogen to male function). However, some dioecious plants appear to conform to this pattern of resource allocation, with different resource types allocated to female vs. male sex functions. Using an evolutionarily stable strategy approach, we show that life-history trade-offs between sexual reproduction and vegetative performance enable the evolution of unisexual phenotypes even when there are no direct resource-based trade-offs between female and male sex functions. This result might help explain the preponderance of perennial life histories among dioecious plants and why many dioecious plants with annual life histories have indeterminate growth with ongoing trade-offs between sexual reproduction and vegetative growth.
大多数雌雄异株植物是多年生的，它们在有性繁殖和营养生长之间存在权衡。然而，这些更广泛的生活史权衡通常没有被纳入对独立性别进化的理论分析中。有一项这样的分析表明，当雌性和雄性性功能涉及将不同类型的资源分配给每个性功能时（例如，将碳分配给雌性功能与将氮分配给雄性功能），雌雄同体比雌雄异体更有利。然而，一些雌雄异株植物似乎符合这种资源分配模式，不同的资源类型分配给雌性和雄性性功能。我们使用进化稳定策略方法表明，有性繁殖和营养生长之间的生活史权衡使得雌雄同体表型的进化成为可能，即使在雌性和雄性性功能之间没有直接的基于资源的权衡。这一结果可能有助于解释为什么在雌雄异株植物中多年生生活史占主导地位，以及为什么许多具有一年生生活史的雌雄异株植物具有不定的生长，在有性繁殖和营养生长之间持续存在权衡。
