Control of Cell Elongation in Nitella by Endogenous Cell Wall pH Gradients: MULTIAXIAL EXTENSIBILITY AND GROWTH STUDIES 1
AUTOR(ES)
Métraux, Jean-Pierre
RESUMO
The multiaxial stress of turgor pressure was stimulated in vitro by inflating isolated Nitella cell walls with mercury. The initial in vitro extension at pH 6.5, 5 atmospheres pressure, returned the wall approximately to the in vivo stressed length, and did not induce any additional extension during a 15-minute period. Upon release of pressure, a plastic deformation was observed which did not correlate with cell growth rates until the final stages of cell maturation. Since wall plasticity does not correlate with growth rate, a metabolic factor(s) is implicated. Walls at all stages of development exhibited a primary yield stress between 0 and 2 atmospheres, while rapidly growing cells (1-3% per hour) exhibited a secondary yield stress of 4 to 5 atmospheres. The creep rate and plastic deformation of young walls were markedly enhanced by acid buffers (10 millimolar, pH ≤ 5.3).
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=440298Documentos Relacionados
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