Rapid effects of boron deficiency on cell wall elasticity modulus in Cucurbita pepo roots

Rinsing roots of Cucurbito pepo with an essentially boron-free nutrient solution results in a significant reduction of the cell wall elasticity modulus as determined by the cell presure probe (measuring always in the same cells). This points to a role of boron in crosslinking cell wall macromolecules. Longer exposure to boron deficient conditions, however, increased Delta P/Delta V again and above the initial values. This trend became visible between 20 and 30 minutes after starting the deficiency treatment. There is no indication for a loss of turgor during the time course of the experiments, suggesting that boron primarily affects cell wall physical properties and that membrane leakiness, as observed by other groups, is a secondary event. Several testable hypotheses for the action of boron are presented.