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Significance of plasmalemma aquaporins for water-transport in Arabidopsis thaliana
Article first published online: 5 JAN 2002
The Plant Journal
Volume 14, Issue 1, pages 121–128, April 1998
How to Cite
Kaldenhoff, R., Grote, K., Zhu, J.-J. and Zimmermann, U. (1998), Significance of plasmalemma aquaporins for water-transport in Arabidopsis thaliana. The Plant Journal, 14: 121–128. doi: 10.1046/j.1365-313X.1998.00111.x
This paper is dedicated to Professor G. Richter on the occasion of his retirement.
- Issue published online: 5 JAN 2002
- Article first published online: 5 JAN 2002
- Received 30 June 1997; revised 19 December 1997; accepted 28 January 1998.
The plant plasma membrane intrinsic protein, PIP1b, facilitates water transport. These features were characterized in Xenopus oocytes and it has asked whether aquaporins are relevant for water transport in plants. In order to elucidate this uncertainty Arabidopsis thaliana was transformed with an anti-sense construct targeted to the PIP1b gene. Molecular analysis revealed that the anti-sense lines have reduced steady-state levels of PIP1b and the highly homologous PIP1a mRNA. The cell membrane water permeability was analyzed by swelling of protoplasts, which had been transferred into hypotonic conditions. The results indicate that the reduced expression of the specific aquaporins decreases the cellular osmotic water permeability coefficient approximately three times. The morphology and development of the anti-sense lines resembles that of control plants, with the exception of the root system, which is five times as abundant as that of control plants. Xylem pressure measurement suggests that the increase of root mass compensates the reduced cellular water permeability in order to ensure a sufficient water supply to the plant. The results obtained by this study, therefore, clearly demonstrate that aquaporins are important for plant water transport.