Grayson Chadwick
Clover root nodule from Beckman Lawn, GPS

Root nodules of legumes contain bacteria that convert nitrogen gas from the atmosphere into bioavailable ammonium for the host plant. A clover root from Beckman lawn was harvested, root sections with attached nodules dissected with a razor blade, and fixed in paraformaldehyde. Roots and nodules were imbedded in methyl methacrylate resin, and cut into semi-thin sections with a glass knife on a microtome. Bacterial cells inhabiting the root nodule were fluorescently labelled with oligonucleotide probes that bind to the bacterial 16s ribosomal RNA (Red). DNA in bacteria and plant nuclei was stained with 4',6-diamidino-2-phenylindole (Blue). Autofluorescence from the plant tissue is visible as well (Green). Scale bar is 1mm.

chadwick@caltech.edu