Premise of study: Increased genomic “material costs” of nitrogen (N) and phosphorus (P) atoms inherent to organisms with larger genome sizes (GS) has been proposed to limit growth under nutrient scarcities and promote growth under nutrient enrichments. Such responsiveness may reflect a nutrient-dependent diploid versus polyploid advantage that could have vast ecological and evolutionary implications, but direct evidence that material costs increase with ploidy-level and/or influence cytotype-dependent growth, metabolic, and/or resource-use tradeoffs is limited.

Methods: We grew diploid, auto-tetraploid, and auto-hexaploid Solidago gigantea plants under one of four ambient and enriched N:P treatments and measured traits related to material costs, primary and secondary metabolism, and resource-use.

Key results: Relative to diploids, polyploids invested more N and P into cells and tetraploids grew more following N-enrichments, suggesting that material costs increase with ploidy-level. Polyploids also generally exhibited strategies that could minimize material-cost-constraints over both long (reduced monoploid GS) and short (more extreme transcriptome downsizing, reduced photosynthesis rates and terpene concentrations, enhanced N-use efficiencies) evolutionary time periods. Furthermore, polyploids had lower transpiration rates but higher water-use-efficiencies than diploids, both of which were more pronounced under nutrient-limiting conditions.

Conclusions: Collectively we found that NP material costs increase with ploidy-level but that material-cost-constraints might be lessened by organismal resource allocation/investment mechanisms that can also alter ecological dynamics and selection. Our results enhance mechanistic understanding of how global increases in nutrients might provide a release from material-cost-constraints in polyploids that could impact ploidy (or GS)-specific performances, cytogeographic patterning, and multispecies community structuring.

JMP Pro Version 16.0 was used to analyze the data, and all files are accessible using Microsoft Excel.