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Biomass accumulation and partitioning of eastern gamagrass grown under different temperature and CO₂ levels
Eastern gamagrass has been reported to have one of the highest photosynthetic rates of any C4 species but data on temperature x CO2 interactions are lacking. This study was conducted to determine the potential effects of future increases of atmospheric carbon dioxide on growth, biomass accumulation and root/shoot carbon allocation under three day/night temperatures and two CO2 levels. Eastern gamagrass (cv. Pete) plants were grown in 1 m3 soil bins containing sand:vermiculite (1:1), fertilized weekly with a complete nutrient solution in closed, transparent SPAR (Soil, Plant, Atmospheric Research) chambers maintained at 370 or 740 micromol mol-1 CO2 and 20/14°, 27.5/21.5° or 35/29°C day/night temperatures, and allowed to develop from mid-May to mid-October. Three harvests were taken during this period. Leaves were collected during the first two harvests. During the final harvest, leaves, crowns, and roots were collected from each individual plant. The optimum day/night temperature under our conditions for biomass accumulation in the leaves (35/29°C) was higher than that for the crowns and roots (27.5/21.5°C). Biomass accumulation in leaves increased two-fold over the entire temperature range. Temperature had a greater effect on vegetative growth than CO2. CO2 enhanced biomass accumulation was modest, restricted to leaves, and observed only at higher temperatures and later in development. Under optimum soil moisture conditions in the SPAR chambers, high amounts of carbon were captured in the above ground biomass for later incorporation into soil. This study demonstrates the potential of eastern gamagrass to capture carbon for sequestration under projected global climate change scenarios.
Gitz, D.C. III
Paper presented at the XXVI International Horticultural Congress on Sustainability of Horticultural Systems in the 21st Century, August 11-17, 2002, Toronto, Canada.
Acta horticulturae 2004 June, no. 638
Journal Articles, USDA Authors, Peer-Reviewed
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