| Abstract Detail
Photosynthesis(Carbon) Zhu, Xin-Guang [1], Long, Stephen P. [2]. What is the signal linking photosynthesis to stomatal conductance? - A theoretical exploration. Stomata respond to a number of external environmental factors such as light, relative humidity, CO2 and O2 concentration. Most external factors influencing stomatal conductance (gs) also influence leaf photosynthesis. ATP is a candidate signal linking photosynthesis to gs. gs also respond to internal factors such as ABA and zeathantin concentrations. Given that the ABA concentration varies with the changes in the operation of xanthophylls cycle upon changes in the lumenal pH when photosynthesis varies, we hypothesize that changes in both [ATP] and [ABA] can explain changes in gs in changing environments. To test this hypothesis, we linked a complete dynamic model of leaf photosynthesis with a detailed model of gs. This whole model includes the complete description of the light reactions, the Calvin cycle, photorespiratory pathway, sucrose synthesis, starch synthesis, and xanthophyll cycle. Furthermore, the regulation of activities of enzymes in these pathways via ferrodoxin-thioredoxin system, Mg2+, lumenal and stromal pH and Rubisco activase were also included. The hydromechanical and biochemical model of gs of Buckley et al. (2003; Plant Cell Env., 26: 1767) was linked to the photosynthesis model using ATP as the signal linking photosynthesis and gs. ABA modulates the ability of ATP to support osmotic gradient across guard cell plastomembrane. Results showed that the model, despite its complexity is numerically stable and realistically simulated the dynamic responses of photosynthesis and gs to changes in external [CO2], [O2], and light.
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1 - University of Illinois at Urbana Champaign, Department of Plant Biology, 1201 W. Gregory Drive, Urbana, IL, 61801, USA
2 - University of Illinois at Urbana Champaign, Department of Plant Biology
Keywords:
Photosynthesis
Computational biology
carbohydrate metabolism
stomatal conductance.
Presentation Type: Plant Biology Abstract
Session: P
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM
Number: P13005
Abstract ID:812 |
