Inhibition of the Dionaea muscipula Ellis trap closure by ion and water channels blockers and uncouplers

The Venus flytrap (Dionaea muscipula Ellis) captures insects with one of the most rapid movements in the plant kingdom. Here we present detailed experiments for comparative study of effects of inhibitors of ion channels, aquaporins, and uncouplers on kinetics of the trap closing stimulated by mechanical or electrical triggering of the trap. Two methods were used: (1) two 10 μL drops of channels blockers or uncouplers were placed on the midrib of the trap or (2) addition of 50 mL of inhibitors to the soil. Both methods of inhibitors extraction give the same effects on the kinetics of the trap closing. Ion and water channel blockers such as HgCl2, tetraethylammonium chloride, ZnCl2, BaCl2, as well as uncouplers CCCP, FCCP, 2,4-dinitrophenol, and pentachlorophenol decrease speed and increase time of the trap closing. We applied for the evaluation of the mechanism of trap closing our new hydroelastic curvature mechanism, which is based on the assumption that the lobes possess curvature elasticity and are composed of outer and inner hydraulic layers with different hydrostatic pressure. The open state of the trap contains high elastic energy accumulated due to the hydrostatic pressure difference between the hydraulic layers of the lobe. Stimuli induce fast water transport from one hydraulic layer to another, and the trap relaxes to the equilibrium configuration corresponding to the closed state. The detailed mechanism of the trap closing is discussed.