Lacey E P, Herr D
Department of Biology, University of North Carolina, Greensboro 27402, USA.
Evolution. 2000 Aug;54(4):1207-17. doi: 10.1111/j.0014-3820.2000.tb00555.x.
To determine the evolutionary importance of parental environmental effects in natural populations, we must begin to measure the magnitude of these effects in the field. For this reason, we conducted a combined growth chamber-field experiment to measure parental temperature effects in Plantago lanceolata. We grew in the field offspring of controlled crosses of chamber-grown parents subjected to six temperature treatments. Each treatment was characterized by a unique combination of maternal prezygotic (prior to fertilization), paternal prezygotic, and postzygotic (during fertilization and seed set) temperatures. Offspring were followed for three years to measure the effects of treatment on several life-history traits and population growth rate, our estimate of fitness. Parental treatment influenced germination, growth, and reproduction of newborns, but not survival or reproduction of offspring at least one year old. High postzygotic temperature significantly increased germination and leaf area at 17 weeks by approximately 35% and 2%, respectively. Probability of flowering and spike production in the newborn age class showed significant parental genotype x parental treatment interactions. High postzygotic temperature increased offspring fitness by approximately 50%. The strongest contributors to fitness were germination and probability of flowering and spike production of newborns. A comparison of our data with previously collected data for chambergrown offspring shows that the influence of parental environment on offspring phenotype is weaker but still biologically meaningful in the field. The results provide evidence that parental environment influences offspring fitness in natural populations of P. lanceolata and does so by affecting the life-history traits most strongly contributing to fitness. The data suggest that from the perspective of offspring fitness, natural selection favors parents that flower later in the flowering season in the North Carolina Piedmont when it is warmer. Genotypic-specific differences in response of offspring reproductive traits to parental environment suggest that parental environmental effects can influence the rate of evolutionary change in P. lanceolata.
为了确定亲代环境效应在自然种群中的进化重要性，我们必须开始在野外测量这些效应的大小。因此，我们进行了一项生长室与野外相结合的实验，以测量披针叶车前草亲代温度效应。我们在野外种植了生长室中经六种温度处理的亲代的受控杂交后代。每种处理的特征是母本合子前（受精前）、父本合子前以及合子后（受精和结籽期间）温度的独特组合。对后代进行了三年的跟踪，以测量处理对几个生活史特征和种群增长率（我们对适合度的估计）的影响。亲代处理影响新生儿的萌发、生长和繁殖，但不影响至少一岁后代的存活或繁殖。合子后高温分别使17周时的萌发率和叶面积显著增加了约35%和2%。新生儿年龄组的开花概率和穗产生表现出显著的亲代基因型×亲代处理相互作用。合子后高温使后代适合度提高了约50%。对适合度贡献最大的是新生儿的萌发、开花概率和穗产生。将我们的数据与之前收集的生长室培养后代的数据进行比较表明，在野外，亲代环境对后代表型的影响较弱，但仍具有生物学意义。结果提供了证据，表明亲代环境影响披针叶车前草自然种群中后代的适合度，并且是通过影响对适合度贡献最大的生活史特征来实现的。数据表明，从后代适合度的角度来看，自然选择有利于在北卡罗来纳州皮埃蒙特温暖的开花季节后期开花的亲本。后代生殖性状对亲代环境反应的基因型特异性差异表明，亲代环境效应可以影响披针叶车前草的进化变化速率。
