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ARS Home » Plains Area » Fort Collins, Colorado » Center for Agricultural Resources Research » Rangeland Resources & Systems Research » Research » Publications at this Location » Publication #349759
Title: Seed traits and germination of native grasses and invasive forbs are largely insensitive to parental temperature and CO2 concentration

Author
item LI, JIN - University Of Saskatchewan
item REN, LEI - University Of Saskatchewan
item BAI, YUGUANG - University Of Saskatchewan
item Lecain, Daniel
item Blumenthal, Dana
item MORGAN, JACK - Retired ARS Employee

Submitted to: Seed Science Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/16/2018
Publication Date: 8/13/2018
Citation: Li, J., Ren, L., Bai, Y., Lecain, D.R., Blumenthal, D.M., Morgan, J. 2018. Seed traits and germination of native grasses and invasive forbs are largely insensitive to parental temperature and CO2 concentration. Seed Science Research. 28(4):303-311. https://doi.org/10.1017/S0960258518000314.
DOI: https://doi.org/10.1017/S0960258518000314

Interpretive Summary: In natural ecosystems plant reproduction by seed has developed and evolved over very long time periods and is assumed to be well adapted to local climate. In the face of global climate change plant fecundity may be altered as climate changes diverge from long-term adaptations. This could have negative effects on plant productivity by seeds. In particular, there is concern that invasive plant species, which characteristically have robust seed production, may gain advantage under climate change disruptions. In this study we collected seeds of native and invasive species over six years from a field study with elevated CO2 (600 ppm) and temperature (2.7/5.4 oF day/night) on the Mixed-grass Prairie of Wyoming, USA. Compared to control plots most seed properties were not altered under climate change treatments. However, there was a trend for changes in the germination requirements of two invasive plant species: Spotted knapweed (Centaurea diffusa) and Dalmation toadflax (Linaria dalmatica). This provides limited evidence that some invasive plant species may thrive under future global climate.

Technical Abstract: The structure and function of grassland ecosystems can be altered by changing climate, including higher temperature and elevated atmospheric CO2 concentration. Previous studies suggest there is no consistent trend in seed germination and seedling recruitment as affected by these conditions. We collected seeds of native and invasive species over six years from a field study with elevated CO2 (600 ppm) and temperature (1.5/3.0 oC day/night) on the Mixed-grass Prairie of Wyoming, USA. Seed fill rate, viability and mass were evaluated and germination tests were conducted under alternating temperatures in growth chambers. Thermal time requirements to reach 50% germination ('50) and base temperatures (Tb) for germination were determined using thermal time models. Climate change conditions had limited effects on seed fill rate, viability and mass. The combination of CO2 enrichment and warming increased germination of Bouteloua gracilis. Centaurea diffusa and Linaria dalmatica, two invasive species in this study, had the lowest '50 and Tb required for germination among all the species studied. Although final germination percentages of these invasive species were not affected by treatments, previous studies reported increased seed production under future climate conditions, indicating that they could be more invasive at the regeneration stage in the future. We concluded projected future temperature increases will have little effect on seed reproductive traits of native species. In addition, the distribution and abundance of B. gracilis and invasive species may be favored by global climate change due to enhanced germination or seed production traits caused by elevated parental CO2 and temperature conditions.