Biology Department, Wesleyan University, Middletown, Connecticut, 06459, USA.
Department of Plant Biology, Michigan State University, East Lansing, Michigan, 48823, USA.
Ecology. 2021 Dec;102(12):e03531. doi: 10.1002/ecy.3531. Epub 2021 Oct 7.
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.
在亲代的一生中，环境条件可以诱导后代出现表型变化，为自然种群中的变异提供了一个潜在的重要来源。然而，迄今为止，生物因素很少被测试为植物跨代效应的来源。在一个有性繁殖一年生植物菥蓂的温室实验中，我们通过分别种植或在竞争排列中种植同基因的亲代植物，并在不同的生长环境中比较它们的幼苗后代，来测试亲代竞争对后代的影响。与非竞争亲代相比，竞争亲代的后代表现出明显的发育改变，导致生物量和总叶面积更大，但仅在邻居或模拟树冠遮荫下生长，而不是在阳光充足干燥的条件下。在后续的一个实验中，亲代植物在干燥的土壤中竞争，发现生长在干燥土壤中的后代，无论是否有竞争者，生长都略有减少。在这两个实验中，亲代竞争的影响都不是由种子供应的变化解释的，这表明存在一种更复杂的调节遗传模式。我们假设，在潮湿土壤中（即主要是为了争夺光照）的亲代竞争赋予了特定的发育效应，这对光照受限的后代是有益的，而在干燥土壤中（即主要是为了争夺地下资源）的亲代竞争产生的后代整体质量略低。总之，这些结果表明，亲代代的竞争条件可以显著促进后代的变异，但这些跨代效应将取决于亲代和后代都可用的非生物资源。
