Plant genome size influences the functional relationships between cellular and whole‐plant physiology, but we know little about its importance to plant tolerance of environmental stressors and how it contributes to range limits and invasion success. We used native and invasive lineages of a wetland plant to provide the first experimental test of the Large Genome Constraint Hypothesis (LGCH)—that plants with large genomes are less tolerant of environmental stress and less plastic under stress gradients than plants with small genomes. We predicted that populations with larger genomes would have a lower tolerance and less plasticity to a stress gradient than populations with smaller genomes. In replicated experiments in northern and southern climates in the United States, we subjected plants from 35 populations varying in genome size and lineage to two salinity treatments. We measured traits associated with growth, physiology, nutrition, defense, and plasticity. Using AICc model selection, we found all plant traits, except stomatal conductance, were influenced by environmental stressors and genome size. Increasing salinity was stressful to plants and affected most plant traits. Notably, biomass in the high‐salinity treatment was 3.0 and 4.9 times lower for the invasive and native lineages, respectively. Plants in the warmer southern greenhouse had higher biomass, stomate density, stomatal conductance, leaf toughness, and lower aboveground percentage of N and total phenolics than in the northern greenhouse. Moreover, responses to the salinity gradient were generally much stronger in the southern than northern greenhouse. Aboveground biomass increased significantly with genome size for the invasive lineage (43% across genome sizes) but not for the native. For 8 of 20 lineage trait comparisons, greenhouse location × genome size interaction was also significant. Interestingly, the slope of the relationship between genome size and trait means was in the opposite direction for some traits between the gardens providing mixed support for LGCH. Finally, for 30% of the comparisons, plasticity was significantly related to genome size—for some plant traits, the relationship was positive, and in others, it was negative. Overall, we found mixed support for LGCH and for the first time found that genome size is associated with plasticity, a trait widely regarded as important to invasion success.

中文翻译：

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植物基因组大小通过可塑性影响入侵植物和本地植物的胁迫耐受性

植物基因组的大小会影响细胞与整个植物生理之间的功能关系，但我们对其对环境胁迫的植物耐受性的重要性及其对范围限制和入侵成功的贡献知之甚少。我们使用湿地植物的原生和入侵谱系提供了大基因组约束假说（LGCH）的第一个实验测试，即具有大基因组的植物比具有小基因组的植物对环境胁迫的耐受性较小，在胁迫梯度下的可塑性较小。我们预测，与具有较小基因组的种群相比，具有较大基因组的种群对应力梯度的耐受性和可塑性较低。在美国北部和南部气候的重复实验中，我们对来自35个种群的基因组大小和谱系不同的植物进行了两种盐度处理。我们测量了与生长，生理，营养，防御和可塑性相关的特征。使用AICc模型选择，我们发现除气孔导度以外的所有植物性状均受环境胁迫因素和基因组大小的影响。盐度的增加对植物有压力，影响了大多数植物的性状。值得注意的是，高盐度处理中的生物量分别为侵入性和天然血统的3.0倍和4.9倍。与北部温室相比，南部温室温度较高的植物具有更高的生物量，气孔密度，气孔导度，叶片韧性以及氮和总酚的地上百分比较低。此外，南部温室对盐度梯度的响应通常要强于北部温室。对于入侵谱系，地上生物量随基因组大小的增加而显着增加（整个基因组大小为43％），但对于自然生物而言则没有。对于20个谱系性状比较中的8个，温室位置×基因组大小的相互作用也很显着。有趣的是，对于为LGCH提供混合支持的花园之间的某些性状，基因组大小与特征均值之间的关系的斜率是相反的。最后，对于30％的比较，可塑性与基因组大小显着相关-在某些植物性状上，这种关系是正的，而在另一些方面，则是负面的。总体而言，我们发现对LGCH的支持不一，并且首次发现基因组大小与可塑性有关，