title: The effects of parental CO2environment on seed quality and subsequent seedling performance in Bromusrubens.
abstract: Seeds were collected and compared from parent plants of Bromusrubens L. (Poaceae), an exotic Mojave Desert annual grass, grown in ambient (360 μmol mol-1) and elevated (700 μmol mol-1) CO2to determine if parental CO2growth conditions affected seed quality. Performance of seeds developed on the above plants was evaluated to determine the influence of parental CO2growth conditions on germination, growth rate, and leaf production. Seeds of B. rubens developed on parents grown in elevated CO2had a larger pericarp surface area, higher C:N ratio, and less total mass than ambient-developed seeds. Parental CO2environment did not have an effect on germination percentage or mean germination time, as determined by radicle emergence. Seedlings from elevated-CO2-developed seeds had a reduced relative growth rate and achieved smaller final mass over the same growth period. Elevated-CO2-developed seeds had smaller seed reserves than ambient seeds, as determined by growing seedlings in sterile media and monitoring senescence. It appears that increased seed C:N ratios associated with plants grown under elevated CO2may have a major effect on seed quality (morphology, nutrition) and seedling performance (e.g., growth rate and leaf production). Since the invasive success of B. rubens is primarily due to its ability to rapidly germinate, increase leaf area and maintain a relatively high growth rate compared to native annuals and perennial grasses, reductions in seed quality and seedling performance in elevated CO2may have significant impacts on future community composition in the Mojave Desert.
authors.affiliation: Department of Biological Sciences, University of Nevada, Las Vegas, Las Vegas, NV 89154-4004, USA e-mail: huxman@nye.nscee.edu, Fax: 702-895-3956, , , , , , US.
authors.forename: Travis E
authors.initials: TE
authors.lastname: Huxman
authors.affiliation: Department of Biological Sciences, University of Nevada, Las Vegas, Las Vegas, NV 89154-4004, USA e-mail: huxman@nye.nscee.edu, Fax: 702-895-3956, , , , , , US.
authors.forename: Erik P
authors.initials: EP
authors.lastname: Hamerlynck
authors.affiliation: Department of Biological Sciences, University of Nevada, Las Vegas, Las Vegas, NV 89154-4004, USA e-mail: huxman@nye.nscee.edu, Fax: 702-895-3956, , , , , , US.
authors.forename: Dean N
authors.initials: DN
authors.lastname: Jordan
authors.affiliation: Department of Biological Sciences, University of Nevada, Las Vegas, Las Vegas, NV 89154-4004, USA e-mail: huxman@nye.nscee.edu, Fax: 702-895-3956, , , , , , US.
authors.forename: Katrina J
authors.initials: KJ
authors.lastname: Salsman
authors.affiliation: Department of Biological Sciences, University of Nevada, Las Vegas, Las Vegas, NV 89154-4004, USA e-mail: huxman@nye.nscee.edu, Fax: 702-895-3956, , , , , , US.
authors.forename: Stanley D
authors.initials: SD
authors.lastname: Smith
keywords: C/N ratio; Elevated CO2; Key wordsBromusrubens; Maternal effects; Mojave Desert