Turgor Pressure Regulation in Valonia utricularis: Effect of Cell Wall Elasticity and Auxin 1
AUTOR(ES)
Zimmermann, Ulrich
RESUMO
The electrical membrane resistance ρ0 of the marine alga Valonia utricularis shows a marked maximum in dependence on the turgor pressure. The critical pressure, Pc, at which the maximum occurs, as well as its absolute value, ρ0max, are strongly volume-dependent. Both Pc and ρ0max, increase with decreasing cell volume. It seems likely, that these relationships reflect the elastic properties of the cell wall, because the volumetric elastic modulus, ε, is also volume-dependent, increasing hyperbolically with cell volume. Both Pc and ρ0max can be affected by external application of indole-3-acetic acid at concentrations of 2·10−7m to 2 ·10−5m. The critical pressure is shifted by 1.2 to 6 bars toward higher pressures and the maximum membrane resistance increased up to 5.6-fold. During the course of the experiments (up to 4 hours), however, IAA had no effect on the volumetric elastic modulus, ε.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=542267Documentos Relacionados
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