Stomatal Opening Involves Polar, Not Radial, Stiffening Of Guard Cells

摘要: It has long been accepted that differential radial thickening of guard cells plays an important role in the turgor-driven shape changes required for stomatal pore opening to occur [1-4]. This textbook description derives from original interpretation structure rather than measurement mechanical properties. Here we show, using atomic force microscopy, although mature display a gradient stiffness, this is not present in immature cells, yet young stomata show normal response. Finite element modeling supports experimental observation stiffening very limited role opening. In addition, our analysis reveals unexpected polar regions complexes, both Arabidopsis and other plants, suggesting widespread occurrence. Combined data (analysis cell wall epitopes treatment tissue with digesting enzymes, coupled bioassay function) plus lead us propose reflects mechanical, pectin-based pinning down ends, which restricts increase complex length during predicted improved response sensitivity aperture movement respect change turgor pressure. Our results provide new insight into mechanics function, negating established view importance providing evidence significant stiffening. Improved performance via altered cell-wall-mediated likely be evolutionary agronomic significance.