Trichloroacetate, an inhibitor of wax biosynthesis, prevents the development of hyperhydricity in Arabidopsis seedlings

Arabidopsis seedlings developed severe hyperhydricity (HH) when 0.2% Gelrite was used to solidify the medium instead of 0.7% agar. One mM trichloroacetate (TCA, an inhibitor of wax synthesis) strongly reduced the amount of wax. TCA also strongly increased the permeability of leaves for water as shown by a decrease of the water retention capacity. One mM TCA also fully prevented HH: the visible symptoms of HH were absent and the amounts of water and air in the intercellular spaces were as in normal, nonhyperhydric seedlings. Apparently, the excess of water that caused the symptoms of HH had been removed by the increased cuticular transpiration in the presence of 1 mM TCA.