Department of Biology, University of Minnesota Duluth, Duluth, Minnesota 55812-3003 USA;
Am J Bot. 2002 Dec;89(12):1899-906. doi: 10.3732/ajb.89.12.1899.
Offspring trait expression is determined by the combination of parental genes and parental environments. Although maternal environmental effects have been widely characterized, few studies have focused on paternal environmental effects. To determine whether light availability influences pollen and offspring traits in the woodland herb Campanula americana, we reared clones of 12 genotypes in two light levels. In the parental generation we measured pollen number and size. Plants grown under high light produced more pollen grains per flower than those grown under low light. However, the response was genotype specific; some individuals responded little to changes in light availability while others substantially reduced pollen production. As a consequence, paternity ratios may vary between light environments if more pollen is associated with greater siring success. We crossed a subset of these plants to produce the offspring generation. The paternal and maternal light environments influenced offspring seed mass, percentage germination, and days to germination, while only maternal light levels influenced later life traits, such as leaf number and size. Maternal and paternal environmental effects had opposite influences on seed mass, percentage germination and days to germination. Finally, there was no direct relationship between light effects on pollen production and offspring trait expression.
后代的特征表达取决于父母基因和父母环境的组合。尽管母体环境效应已被广泛研究，但很少有研究关注父体环境效应。为了确定光照条件是否会影响林地草本风铃草的花粉和后代特征，我们在两种光照水平下培养了 12 种基因型的克隆。在亲代中，我们测量了花粉数量和大小。在高光条件下生长的植物比在低光照条件下生长的植物每朵花产生的花粉粒数更多。然而，这种反应具有基因型特异性；一些个体对光照条件的变化反应不大，而另一些个体则大大减少了花粉的产生。因此，如果更多的花粉与更大的父系成功相关，那么父体环境可能会影响亲子关系比例。我们从这些植物中选择了一部分进行杂交，产生了后代。父体和母体光照环境影响后代种子质量、发芽率和发芽天数，而只有母体光照水平影响后期生活特征，如叶片数量和大小。母体和父体环境效应对种子质量、发芽率和发芽天数有相反的影响。最后，花粉产生的光照效应与后代特征表达之间没有直接关系。
