Figure 2From: Variable-angle total internal reflection fluorescence microscopy of intact cells of Arabidopsis thalianaOptical analysis of light paths in VAEM and TIRFM observations in plant cells. (A) When the aqueous film between the cover glass and the cell wall is thick (> 100 nm) and θ i is greater than 61.0° (θ c ), all light energy is reflected at the g/am interface. The EW field forms in the aqueous medium but cannot penetrate into the cytosol. (B) When θ i is less than 61.0° (θ c ), a VAE field forms, illuminating the cytosol with variable depth. Angles of refraction for all optical boundaries with θ i = 60.0° are shown. (C) When the aqueous film is sufficiently thin (< 100 nm), and θ i is smaller than θ c for g/cw (θ c2 ) but greater than θ c for g/c (θ c1 ) [(i.e., θ c1 <θ i < θ c2 )], an EW field of constant depth is created inside the cytosol at the cw/c interface. (D) When θ i > θ c2 , the light is completely reflected at the cell wall interface, and the EW field is not deep enough to penetrate into the cytosol. (E) Optical parameters of plant-cell peripheral boundaries. In the situation shown in (A), the EW field is 105 nm deep and cannot penetrate the cell wall. In the situation shown in (C) and with θ i = 67.0°, the EW field penetrates 159 nm into the cytosol. CW: cell wall; EW: evanescent wave; PM: plasma membrane; VAE: variable-angle epifluorescence.Back to article page