Abstract Detail

Ecology

Walczyk, Angela [1], Hersch-Green, Erika [1].

Investigating phenotypic plasticity within the cytotype complex of Solidago gigantea Aiton (Giant Goldenrod, Asteraceae).

Relative to diploids, polyploids have been hypothesized to exhibit increased phenotypic plasticity (PP), which are thought to have contributed, in part, to the colonization and establishment success of polyploids. However, empirical support showing that polyploids exhibit increased PP relative to diploids and/or lower ploidy levels are rare. In this study, we examined whether PP scales with ploidy level in the allopolyploid Solidago gigantea Aiton. We grew diploid, tetraploid, and hexaploid S. gigantea in an outside potted experiment with pots containing either low, medium, or high soil nitrogen and phosphorus levels and measured four growth (above- and belowground biomass, root/shoot ratio, height) and three physiological (photosynthetic capacity, transpiration rate, water use efficiency) traits. We chose to vary these nutrients because larger genomes are predicted to be more limited by nitrogen and phosphorus scarcities than smaller genomes. While we predicted that all plants would experience increases biomass accumulation and plant productivity as nutrients became more plentiful, we specifically hypothesized that larger ploidy levels would experience more pronounced gains in these traits and would thus display greater PP as nutrient availability increased. All cytotypes experienced enhancements to above- and belowground biomasses and height as nutrients increased, but contrary to our expectations, PP did not correlate with ploidy level. Instead, diploids and tetraploids displayed more PP than hexaploids, in terms of above- and belowground biomasses and height, as nutrient availability increased from low to medium. As nutrient availability increased from medium to high, diploids were less plastic than hexaploids and tetraploids for aboveground biomass accumulation and height, respectively. Interestingly, cytotypes displayed different investment strategies into root versus shoot growth as nutrient levels increased. As nutrients became more available, diploids invested more into root growth, while tetraploids invested more into shoot growth and hexaploids consistently invested into root growth across treatments. Analyses of physiological traits are pending. These preliminary results do not support our original hypotheses, but instead suggests that the nutrient environment differentially affects the size and plasticity responses of some traits depending on a plant’s ploidy level. This study is one of the few explicitly testing the influence of polyploidy on PP within a complete cytotype complex and it is among a growing number of studies demonstrating that PP does not scale with ploidy level alone. Future studies investigating whether observed correlations between ploidy level and PP are species and/or trait specific are warranted.

1 - Michigan Technological University, 1400 Townsend Drive, DOW Building, Houghton, MI, 49931, United States

Keywords:
polyploidy
Whole genome duplication
nitrogen
phosphorus
phenotypic plasticity
goldenrod
genome size.

Presentation Type: Oral Paper
Session: ECO2, Ecology: Invasion Biology
Location: /
Date: Tuesday, July 20th, 2021
Time: 12:45 PM(EDT)
Number: ECO2002
Abstract ID:311
Candidate for Awards:Ecological Section Best Graduate Student Paper