PARENT SESSION

Symposium S1C Photosynthate transport and transporters
Monday August 30th, 2004 10:20 AM-12:20 PM Room 510A
Chair: Andreas Weber
Co-Chair: Marinus Pilon

CO₂ permeability in plants is modified by aquaporins. Ralf Kaldenhoff^*,1, ¹ Institute of Botany, Darmstadt University of Technology, Darmstadt, Germany

ABSTRACT- A general overview about aquaporins will be presented. Taking a plasma membrane aquaporin from tobacco (NtAQP1) as an example the experimental principles of water and CO2 permeability-analysis in heterologous expression systems will be given. The results indicated that NtAQP1 has a function as an aquaporin and a membrane gas pore. Expression and protein localization of this aquaporin suggest a function in development and osmoregulated processes. Using tobacco antisense and induced overexpression of NtAQP1, evidence was found for the significance of the aquaporin to cellular transport processes and whole plant physiology. A variation of NtAQP1 expression changed CO2 limited or regulated processes like photosynthesis rate respectively kinetics of stomata opening. Yet unpublished data from molecular and physiological studies confirming the effects of NtAQP1 CO2 permeability in plant tissues will be presented and a model including the CO2 pore function of aquaporins for CO2 dependent processes will be outlined.

KEY WORDS: CO2, aquaporin