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Tobacco aquaporin NtAQP1 is involved in mesophyll conductance to CO2 in vivo

Flexas, J. and Ribas-Carbo, M. and Hanson, D. T. and Bota, J. and Otto, Beate and Cifre, J. and McDowell, N. and Medrano, H. and Kaldenhoff, Ralf (2006):
Tobacco aquaporin NtAQP1 is involved in mesophyll conductance to CO2 in vivo.
In: The plant journal, pp. 427-439, 48, [Article]

Item Type: Article
Erschienen: 2006
Creators: Flexas, J. and Ribas-Carbo, M. and Hanson, D. T. and Bota, J. and Otto, Beate and Cifre, J. and McDowell, N. and Medrano, H. and Kaldenhoff, Ralf
Title: Tobacco aquaporin NtAQP1 is involved in mesophyll conductance to CO2 in vivo
Language: English
Journal or Publication Title: The plant journal
Volume: 48
Divisions: 10 Department of Biology
10 Department of Biology > Applied Plant Sciences
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Date Deposited: 20 Nov 2008 08:24
Additional Information:

ePub 2006 Sep 29

License: [undefiniert]
Alternative Abstract:
Alternative abstract Language
Leaf mesophyll conductance to CO(2) (g(m)) has been recognized to be finite and variable, rapidly adapting to environmental conditions. The physiological basis for fast changes in g(m) is poorly understood, but current reports suggest the involvement of protein-facilitated CO(2) diffusion across cell membranes. A good candidate for this could be the Nicotiana tabacum L. aquaporin NtAQP1, which was shown to increase membrane permeability to CO(2) in Xenopus oocytes. The objective of the present work was to evaluate its effect on the in vivo mesophyll conductance to CO(2), using plants either deficient in or overexpressing NtAQP1. Antisense plants deficient in NtAQP1 (AS) and NtAQP1 overexpressing tobacco plants (O) were compared with their respective wild-type (WT) genotypes (CAS and CO). Plants grown under optimum conditions showed different photosynthetic rates at saturating light, with a decrease of 13% in AS and an increase of 20% in O, compared with their respective controls. CO(2) response curves of photosynthesis also showed significant differences among genotypes. However, in vitro analysis demonstrated that these differences could not be attributed to alterations in Rubisco activity or ribulose-1,5-bisphosphate content. Analyses of chlorophyll fluorescence and on-line (13)C discrimination indicated that the observed differences in net photosynthesis (A(N)) among genotypes were due to different leaf mesophyll conductances to CO(2), which was estimated to be 30% lower in AS and 20% higher in O compared with their respective WT. These results provide evidence for the in vivo involvement of aquaporin NtAQP1 in mesophyll conductance to CO(2).English
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