FIGURE 3.

Transmission electron micrographs of A. thaliana cells. A, top left, wild type, no ciprofloxacin. Top right, ciprofloxacin-resistant gyra-3 plant, no ciprofloxacin. Bottom left, wild type, 10 μm ciprofloxacin (this micrograph is from a chlorotic area of the leaf). Bottom right, ciprofloxacin-resistant gyra-3 plant, 10 μm ciprofloxacin. All scale bars are 2 μm. B, transmission electron micrographs of ciprofloxacin-resistant and wild-type plants after growth on media containing 10 μm ciprofloxacin, with the endosymbiotic organelles labeled. The mitochondria have similar morphologies in both plants. In the ciprofloxacin-resistant plant, the chloroplasts have the same appearance as in wild-type plants grown on drug-free media. However, in the wild-type plant grown on ciprofloxacin, the thylakoids are less well ordered, and chloroplast division may have been inhibited. Both scale bars are 2 μm.