Conditions during a parent’s lifetime can induce phenotypic changes in offspring, providing a potentially important source of variation in natural populations. Yet, to date, biotic factors have seldom been tested as sources of transgenerational effects in plants. In a greenhouse experiment with the generalist annual Polygonum persicaria, we tested for effects of parental competition on offspring by growing isogenic parent plants either individually or in competitive arrays and comparing their seedling progeny in contrasting growth environments. Offspring of competing vs. non-competing parents showed significantly altered development, resulting in greater biomass and total leaf area, but only when growing in neighbor or simulated canopy shade, rather than sunny dry conditions. A follow-up experiment in which parent plants instead competed in dry soil found that offspring in dry soil had slightly reduced growth, both with and without competitors. In neither experiment were effects of parental competition explained by changes in seed provisioning, suggesting a more complex mode of regulatory inheritance. We hypothesize that parental competition in moist soil (i.e., primarily for light) confers specific developmental effects that are beneficial for light-limited offspring, while parental competition in dry soil (i.e., primarily for belowground resources) produces offspring of slightly lower overall quality. Together, these results indicate that competitive conditions during the parental generation can contribute significantly to offspring variation, but these transgenerational effects will depend on the abiotic resources available to both parents and progeny.

中文翻译：

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对比条件下亲本植物竞争对后代发育的跨代影响

父母一生中的条件会引起后代的表型变化，为自然种群的变异提供一个潜在的重要来源。然而，迄今为止，生物因素很少被作为植物跨代效应的来源进行测试。在温室试验中使用多才多艺的一年生蓼蓼，我们通过单独或以竞争性阵列种植同基因亲本植物并在对比生长环境中比较它们的幼苗后代来测试亲本竞争对后代的影响。竞争与非竞争亲本的后代表现出显着改变的发育，导致更大的生物量和总叶面积，但仅当在邻居或模拟树冠遮荫下生长时，而不是在阳光充足的干燥条件下生长。在干土中进行竞争的亲本植物的后续实验发现干土中的后代在有和没有竞争者的情况下生长略有下降。在这两个实验中，父母竞争的影响都不能用种子供应的变化来解释，这表明了一种更复杂的调控遗传模式。我们假设父母在潮湿土壤中的竞争（即，主要用于光照）赋予对光照受限的后代有益的特定发育效应，而在干燥土壤中的亲本竞争（即主要针对地下资源）产生的后代总体质量略低。总之，这些结果表明亲代期间的竞争条件可以显着促进后代变异，但这些跨代效应将取决于父母和后代可用的非生物资源。