Maternal environment affects adaptive seed and seedling traits in Elymus elymoides

In the last 30 years, extensive restoration efforts in Western US states have been prompted by high-intensity wildfires, invasion by introduced species, and the effects of climate change. However, restoration seed needs often outpace the volume of seed that can be collected from the wild, so seeds for many native plant species must be produced in agricultural fields before they are seeded in wild settings. For many of these efforts, agricultural conditions vary significantly from wild restoration conditions, so it is important to understand if and how agricultural field conditions affect the establishment and survival of such seeds. Here, we ask how potentially adaptive traits of bottlebrush squirreltail (Elymus elymoides), a common restoration grass used in the Great Basin, are affected by its maternal growing environment. We grew a wild-sourced, agriculturally produced population under 6 maternal environments representing conditions ranging from high resource with high intraspecific densities to low resource, high interspecific density conditions, and also compared these seeds to the farmed generation. We measured survival, size, phenology, and seed output for maternal plants, along with seed and seedling traits of progeny, asking how maternal environment affected a variety of trait responses. Traits measured included seed mass, seed fill, seed coat surface area (SA), endosperm SA, seed coat eccentricity index (EI), endosperm EI, endosperm to seed coat ratio (E:S), emergence date, health rating, plant size, leaf count, total biomass, and root to shoot ratio (root: shoot). Maternal treatment had strong effects on all responses tested, with higher-resource maternal environments producing more and heavier seeds with more consistent fill. However, seeds from higher-resource treatments also had lower emergence and emerged later than lower-resource treatments, with mean emergence date varying by 8 days between the earliest-emerging group and the latest-emerging group. Lower-resource groups were also more likely to emerge nocturnally. These lower-resource treatments also produced bigger plants which survived better in drought treatments, which was surprising, given that higher-resource seeds were larger. Our results lend support to a "sweet spot" approach to seed increase, where tradeoffs between the advantages of potentially adaptive traits for plants grown in challenging maternal environments need to be balanced with the benefits of high seed production in traditional agricultural practices in restoration seed increase.

Level thesis:degree_level

Master's Degree

Year dc:date.issued

2022

Author dc:creator

• Frederick, Rosemary L

Advisor dc:contributor.advisor

• Leger, Elizabeth

Committee members dc:contributor.committeemember

• Shriver, Robert
• Badik, Kevin

• Elymus elymoides
• Great Basin
• maternal effects
• nocturnal emergence
• restoration
• seed traits

Handle dc:identifier.uri

http://hdl.handle.net/11714/8423

OAI identifier oai:identifier

oai:scholarwolf.unr.edu:11714/8423