Abstract
The rising concentration of atmospheric carbon dioxide (CO2) is known to directly affect plants, increasing growth, yield, and resource use efficiency. Further, research has shown that sweetpotatoes (Ipomoea batatas) represent a potential source for bioethanol production, particularly industrial cultivars bred specifically for this purpose. However, the effects of elevated CO2 on these new industrial cultivars of sweetpotato remain uninvestigated. We grew industrial cultivar CX-1 sweetpotato plants in open top field chambers exposed to either ambient or elevated (ambient+200 μmol mol−1) CO2 for one growing season and examined growth and allocation responses. Growth in elevated CO2 increased biomass production for cultivar CX-1. In particular, total storage root dry weight increased by 40.9% compared to plants grown in ambient CO2. Fresh weight allocation to belowground plant organs (fine roots and storage roots) also increased under elevated CO2, but dry weight partitioning was unaffected. Aboveground (vines plus leaves) dry weight: fresh weight ratio was increased by elevated CO2, indicating possible alterations in tissue anatomy and/or chemistry. Our findings indicate that the industrial sweetpotato cultivar CX-1 has potential as a source for bioethanol production, and this potential could be enhanced as atmospheric CO2 continues to rise.
