Studies on effects of the outbreeding depression on reproduction and regeneration of rare tree species grown in wet lands

我们研究了长距离杂交和种群间杂交对湿地珍稀树种远交衰退的影响。结果表明，在生活史早期阶段，种群间的适合度（果花比和籽胚珠比）发生了杂交，表现出远交衰退，种群内配偶间距离与幼苗生长量呈负相关。另一方面，玉兰树没有表现出远交衰退，由于种群间杂交在早期生活阶段。种群间杂交产生了积极的影响（即，杂种优势），而不是负面影响（远交衰退）对树木的健身组件在一个孤立的M。stellata种群

We examined effects of outbreeding depression due to long-distance crossing and inter-population crossing in rare tree species grown in wet lands. Acer pycnunthum trees exhibited outbreeding depression due to inter-population crossing in fitness components at the early life stage (fruit/flower ratio and seed/ovule ratio) and negative correlation between distance between mates and growth increment for its seedlings within a population. On the other hand, Magnolia stellata trees did not exhibit outbreeding depression due to inter-population crossing at the early life stage. The inter-population crossing resulted in positive effects (i.e., heterosis) rather than negative effects (outbreeding depression) on the fitness components of trees in an isolated M. stellata population.