Figure 4.

Axenic plants infected with bacterial strain BJ2 (A and C) had increased root-hair production compared with axenic plants (B and D) supplied with 0 and 20 μm selenate in agar medium. Seedlings were germinated from surface-sterilized seeds coated with or without bacteria in a methylcellulose paste, stained with acridine orange, and observed at 5× magnification. Similar results were observed when strain BJ15 was used and when the root tips were observed at 10× magnification by confocal microscopy. Bars = 100 μm.