Fig. 4.

FLIM estimation of intracellular pH in arabidopsis seedlings exposed to 100 µm AlCl₃ for 1 h. In each case the right panels show the lifetime distribution of the 2′,7′-bis-(2-carboxyethyl)-5-( and-6)-carboxyfluorescein acetoxymethyl ester (BCECF) for the area located within the free shapes drawn with a red line or rectangular formed by the white lines. The colour distribution in microphotographs in the left panels is based on BCECF lifetime distribution that was calculated and presented in the right panels. The mean pH is more acidic in the external cells (one or two layers of the surface cells) of both root zones.