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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Adaptive Cropping Systems Laboratory » Research » Publications at this Location » Publication #349950
Title: Evidence of adaptation to recent changes in atmospheric CO2 in four weedy species

Author
item BUNCE, JAMES - Retired ARS Employee

Submitted to: Plants
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/14/2018
Publication Date: 2/19/2018
Citation: Bunce, J.A. 2018. Evidence of adaptation to recent changes in atmospheric CO2 in four weedy species. Plants. 7(1):12. https://doi.org/10.3390/plants7010012.
DOI: https://doi.org/10.3390/plants7010012

Interpretive Summary: The concentration of carbon dioxide in the atmosphere increased from about 320ppm in 1966 to about 380ppm in 2006. It continues to increase and has effects on the growth rate of both crops and the weeds which compete with crops. This study tested whether four weedy species have changed genetically between 1966 and 2006 in ways which make them grow faster as carbon dioxide concentration rises. The results provided several different lines of evidence that adaptation of these weedy species has occurred to the change in atmospheric carbon dioxide in ways which increase their ability to compete with crops. This work will be of interest to agronomists concerned with competition between weeds and crops as climate changes.

Technical Abstract: Seeds of three C3 and one C4 annual weedy species were collected from agricultural fields in Beltsville, Maryland in approximately 1966 and 2006, when atmospheric CO2 concentrations averaged about 320 and 380 'mol mol-1, respectively. Plants from each collection year were grown over a range of CO2 concentrations to test for adaptation of these weedy species to these recent changes in atmospheric CO2. In all three of the C3 species, the increase in CO2 concentration from 320 to 380 'mol mol-1 increased total dry mass at 24 days in plants from seeds collected in 2006, but not in plants from seeds collected in 1966. Shoot and seed dry mass at maturity was greater at the higher growth CO2 in plants collected in 2006 than in 1966 in two of the species. Down regulation of photosynthetic carboxylation capacity during growth at high CO2 was less in the newer seed lots than in the older in two of the species. Overall, the results indicate that adaptation to recent changes in atmospheric CO2 has occurred in some of these weedy species.