FIG. 5.

Bacterial attachment to alfalfa root segments. (A and B) Wild-type strain C58 incubated with roots. Bacteria bound to the root hairs (A) and to the cut end of the root (B). (C and D) AttR mutant A205 bacteria incubated with roots. The mutant bacteria bound to the root hairs (C) but failed to bind to the cut ends of the roots (D). The arrow indicates the location of an individually attached bacterium. The arrowheads indicate the locations of clusters of attached bacteria. Although not shown, wild-type and mutant bacteria also bound to the root epidermis and root cap. Equal numbers of bacteria were present in all incubations. Bars, 5 μm.