|Rogers Jr, Hugo|
|Prior, Stephen - Steve|
|VAN SANTEN, EDZARD|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 10/1/1999
Publication Date: N/A
Citation: Rogers, H.H., Prichard, S.G., Prior, S.A., and Van Santen, E. 1999. Root growth in CO2-enriched agricultural systems. 5th New Phytologist Symposium and GCTE Workshop. Root Dynamics and Global Change: An Ecosystem Perspective. Townsend, TN. October 19-22.
Technical Abstract: Crop growth in CO2-enriched air usually results in marked changes in root growth and development. Increased carbohydrates stimulate root growth either directly (functioning as substrates) or indirectly (functioning as signal molecules) by enhancing cell division, expansion, or both. The literature indicates that initiation and stimulation of lateral roots will be favored over the elongation of primary roots leading to more branched and shallower root systems. Such shifts in root system architecture may lead to reduced uptake efficiency, perhaps contributing to the often observed reductions in specific root activities. Allocation of carbon to roots fluctuates over the plants life cycle, so neither physiology nor development should be viewed as static. In annual crops, carbon going to belowground processes changes as the plant switches from vegetative to reproductive growth. Reductions in carbon allocation to roots over time may induce temporal shifts in root deployment, perhaps affecting demography. The paucity of data notwithstanding, particularly for annual crops, fine root turnover will likely go up as a function of greater fine root biomass. Changes in turnover arising from decreased root longevity in crops are unlikely, however. Knowledge of changing carbon allocation to roots, a more thorough understanding of mechanistic controls on root longevity, and better characterization of rooting habits will advance our comprehension of how rising CO2 will influence root demography. Such knowledge will enable us to better elucidate the linkage of atmosphere with belowground plant function, and in turn, plant function with soil biology and structure.