The Role of Light-Induced Membrane Potential Changes in Guttation in Gametophytes of Asplenium trichomanes

Abstract

Gametophytes of the fern Asplenium trichomanes exhibit guttation when illuminated. Membrane potential changes evoked by light were measured in the presence of ion channel and proton pump inhibitors to elucidate the nature of the response and a possible link to guttation. Light-induced depolarization was suppressed by the anion channel inhibitors: anthracene-9-carboxylic acid and niflumic acid. Potassium channel blockers: TEA and Ba2+ caused an increase of the amplitude of light-induced membrane potential changes. Calcium channel inhibitors, La3*, Gd3+, diltiazem, nifedipine and verapamil had no significant effect on the membrane potential changes. Similarly, proton pump inhibitors, diethylstilbestrol and vanadate, had only minor effects on the response. A possible role of Cl~ and K+ fluxes in light-induced guttation is discussed.