David Des Marais

Date & Time: November 18, 2024, at 4 pm

Location: BCH 101

Zoom: https://msu.zoom.us/j/91993518218
Meeting ID: 919 9351 8218
Passcode: 028299

Host: Patrick Edger

About the Speaker

Institution: Massachusetts Institute of Technology

Subject: The physiological causes and consequences of resource allocation in grasses

Abstract: Life history in plants is often discretized into annual, biennial, and perennial strategies, obscuring the complex set of interacting traits that comprise these syndromes. The historical focus on the timing and frequency of reproduction reflect this simplification in the literature. Exploiting the model grass genus Brachypodium, I present a three-part re-assessment of life history transitions in grasses, focusing on growth rate, investment in reproductive effort, and components of carbon assimilation and partitioning. First, I show that annual plants grow more rapidly on a per-mass basis than perennial congeners but find limited support for the hypothesis that annuals and perennials differentially allocate biomass to above- and below-ground structures in their first year of growth. Second, I show that environmental stressors result in differential investment in reproduction vs survivorship in annuals and perennials, and highlight possible regulatory drivers of this evolutionary difference. Finally, I perform a series of quantitative genetic analyses using intraspecific diversity panels of two grasses to assess the relative contributions drivers of growth rate variation. I conclude that annuals and perennials are best considered to occur along a spectrum of life history strategies and that careful consideration of multiple components of these syndromes will likely provide better insight into the frequent evolutionary transitions observed across land plants.