Abstract
Metal cation treatments of cell walls reduce the extension of cell walls. It is proposed that the wall extension is regulated by adjusting wall extensibility (φ) and yield threshold tension (y). In order to determine whether metal cations affect φ or y, we examined the extension of metal cation-treated walls with a custom-made extensometer and glycerinated hollow cylinders (GHCs) of cowpea.
The y of untreated GHCs was about 70gw at pH4.0. However the y of GHCs treated with 1mM CaCl2 increased to about 115gw. But the φ was almost unchanged. We also examined the effect of Mg2+, Cu2+ or Al3+ treatment on the wall mechanical properties, and found that the y increased to about 100gw, 100gw, 90gw, respectively. Based on the results, we concluded that the reduction of the wall extension induced by metal cations was caused by the increase of the y.
