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ARS Home » Research » Publications at this Location » Publication #68259
Title: CARBON DIOXIDE ENRICHMENT IMPROVES WATER RELATIONS AND SURVIVAL OF DROUGHTED HONEY MESQUITE SEEDINGS

Author
item Polley, Herbert
item Johnson, Hyrum
item Mayeux Jr, Herman
item Tischler, Charles
item Brown, Daniel

Submitted to: Ecological Society of America Bulletin
Publication Type: Abstract Only
Publication Acceptance Date: 2/17/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Low water availability reduces establishment of the invasive shrub Prosopis on some grasslands. Survival of water deficit and traits that may contribute to the postponement or tolerance of dehyration were measured on seedlings of P. glandulosa (honey mesquite) grown at three CO2 concentrations (380, 700, and 1000 ppm). Soil water content was depleted at similar rates across CO2 treatments by increasing the number of seedlings per container at elevated concentrations. Elevating CO2 increased root biomass and the ratio of lateral root to total root biomass of seedlings, but plants grown at elevated CO2 shed leaves faster than did those grown at 380 ppm. These changes contributed to an increase in xylem pressure potential at 1000 ppm during the first 37 days of growth (0.26 to 0.40 MPa). Osmotic potential was not affected by CO2. Elevating CO2 to 700 and 1000 ppm more than doubled survival of seedlings from which water was withheld for 65 days, and increased survival from 0% to about 40% among seedlings that experienced lowest soil water levels. By increasing seedling survival, rising CO2 may increase abundance of P. glandulosa on grasslands where low water availability limits its establishment.