Abstract Detail

Ecology

Anneberg, Thomas [1], Turcotte, Martin [2], Ashman, Tia-Lynn [3], O’Neill, Elizabeth [1].

The effect of neopolyploidy on population demography across nutrient environments in Spirodela polyrhiza.

Populations of nascent polyploids, or neopolyploids, are expected to be highly susceptible to extinction shortly after they arise due in part to being the minority cytotype in an otherwise diploid community. Further reducing the odds of neopolyploid persistence, and ultimately their establishment, is the accumulating evidence that neopolyploidy exacerbates the need for growth-limiting nutrients. Notably, all of the comparisons between diploids and their neopolyploid descendants in response to nutrient supply have been assessed at the level of individual. However, neopolyploid establishment is a population-level process and it is thus critical that we focus on population-level traits such as population sizes over time and mortality rates in order to better predict which ecological contexts favor neopolyploid persistence and allow establishment to occur. We thus posed the question: are neopolyploid populations more sensitive to nutrient supply than diploids? To address this question, we conducted a factorial nutrient addition experiment using monoculture populations of diploid or neopolyploid Spirodela polyrhiza. To discern the relative effect of genotype and neopolyploidy in our study, we included four independent lineages comprised of a diploid and colchicine-induced neopolyploid sub-lineage. To understand how both the concentration of nutrients and the relative ratio of supply between these nutrients affects these populations, we treated the plants with nine nutrient environments that varied in nitrogen and phosphorus concentration and ratio, ranging from 0.14 – 14 mg/L nitrogen and 0.01 – 1 mg/L phosphorus, resulting in a range of N:P ratios from 0.14 - 1400. A separate experiment with high resources will also be discussed. We measured three population demographic traits in our experiment: population sizes over time, mortality rates, and turion production which are dormant buds that serve as an asexual seed-banking mechanism for S. polyrhiza. Since neopolyploidy commonly increases individual body size, we also measured the relative productivity and concentrations of nitrogen and phosphorus that populations sequestered into their tissues, with the expectation that neopolyploid populations are more productive due to increased individual mass. Preliminary results suggest that there is a strong genotype by ploidy interaction on the ability of populations to grow and produce turions across nutrient environments, as well as a general pattern of neopolyploid populations being fewer in number but producing more biomass compared to their diploid ancestors. From these population-level traits, we conclude that the nutrient environment can be an important driver of neopolyploidy establishment.

1 - University of Pittsburgh, Biological Sciences, 4249 Fifth Ave, Pittsburgh, PA, 15260, USA
2 - University of Pittsburgh, Biological Sciences, 4249 Fifth Ave, Pittsburgh, PA, 15260, United States
3 - University of Pittsburgh, Biological Sciences, 4249 Fifth Avenue, Pittsburgh, PA, 15260, USA

Keywords:
polyploidy
nutrients
ecological stoichiometry
abiotic stress.

Presentation Type: Oral Paper
Session: ECO5, Ecology: Stress
Location: /
Date: Thursday, July 22nd, 2021
Time: 12:30 PM(EDT)
Number: ECO5001
Abstract ID:823
Candidate for Awards:None