Department of Biology, Trent University, 1600 West Bank Drive, Peterborough, ON, K9J 7B8, Canada.
New Phytol. 2012 Oct;196(2):606-616. doi: 10.1111/j.1469-8137.2012.04260.x. Epub 2012 Aug 16.
Many plants combine sexual reproduction with vegetative propagation, but how trade-offs between these reproductive modes affect fitness is poorly understood. Although such trade-offs have been demonstrated at the level of individual shoots (ramets), there is little evidence that they scale up to affect genet fitness. For hermaphrodites, reproductive investment is further divided between female and male sexual functions. Female function should generally incur greater carbon costs than male function, which might involve greater nitrogen (N) costs. Using a common garden experiment with diclinous, clonal Sagittaria latifolia we manipulated investment in reproduction through female and male sex functions of 412 plants from monoecious and dioecious populations. We detected a 1:1 trade-off between biomass investment in female function and clonal reproduction. For male function, there was no apparent trade-off between clonal and sexual reproduction in terms of biomass investment. Instead, male function incurred a substantially higher N cost. Our results indicate that: trade-offs between investment in clonal propagation and sexual reproduction occur at the genet level in S. latifolia; and sexual reproduction interferes with clonal expansion, with investment in female function limiting the quantity of clonal propagules produced, and investment in male function limiting the nutrient content of clonal propagules.
许多植物将有性繁殖与营养繁殖相结合，但这些繁殖模式之间的权衡如何影响适应性还知之甚少。尽管已经在个体枝（分株）水平上证明了这种权衡，但很少有证据表明它们可以扩展到影响遗传适应性。对于雌雄同体植物，生殖投资进一步分为雌性和雄性生殖功能。雌性功能通常比雄性功能消耗更多的碳，这可能涉及更高的氮（N）成本。利用具有雌雄同体、克隆的荸荠（Sagittaria latifolia）的共同花园实验，我们通过来自雌雄同体和雌雄异株种群的 412 株植物的雌性和雄性生殖功能来操纵繁殖投资。我们检测到在雌性生殖功能和克隆繁殖之间存在 1:1 的权衡关系。对于雄性生殖功能，在克隆和有性生殖之间的生物量投资方面，没有明显的权衡关系。相反，雄性生殖功能会产生更高的 N 成本。我们的研究结果表明：在荸荠中，克隆繁殖和有性生殖之间的投资权衡发生在遗传水平上；有性生殖会干扰克隆扩张，雌性生殖功能的投资限制了克隆繁殖体的数量，而雄性生殖功能的投资限制了克隆繁殖体的养分含量。
