| Popis: |
Cellular exchange of carbon dioxide (CO(2) ) is of extraordinary importance for life. Despite this significance, its molecular mechanisms are still unclear and a matter of controversy. In contrast to other living organisms, plants are physiologically limited by the availability of CO(2) . In most plants, net photosynthesis is directly dependent on CO(2) diffusion from the atmosphere to the chloroplast. Thus, it is important to analyze CO(2) transport with regards to its effect on photosynthesis. A mutation of the Arabidopsis thaliana AtPIP1;2 gene, which was characterized as a non-water transporting but CO(2) transport-facilitating aquaporin in heterologous expression systems, correlated with a reduction in photosynthesis under a wide range of atmospheric CO(2) concentrations. Here, we could demonstrate that the effect was caused by reduced CO(2) conductivity in leaf tissue. It is concluded that the AtPIP1;2 gene product limits CO(2) diffusion and photosynthesis in leaves. |
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