کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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2826669 | 1162258 | 2010 | 7 صفحه PDF | دانلود رایگان |
Significant controversy still swirls around the regulation of extension by tip-growing cells, particularly during stable, oscillatory growth of pollen tubes. One explanation proposes that turgor pressure is both the controlling and driving force. We refute this hypothesis on theoretical and evidentiary grounds. Direct measurement of intracellular pressure reveals constant turgor even as growth rates change. Measured ion fluxes, notably potassium, are insufficient to account for the requisite osmotic changes. Water movement, and hence pressure gradients, occur throughout the cell, unrestricted to local domains. Increases in hydrostatic pressure alone would force water out of the cell rather than cause increased growth. We have recently demonstrated concomitant changes in the apical cell wall that account fully for observed changes in growth rate.
Journal: - Volume 15, Issue 7, July 2010, Pages 363–369