Charlotte J. Avers

An Evaluation of Various Fixing and Staining Procedures for Mitochondria in Plant Root Tissues

Mitochondria were stained intensely by a Regaud iron-hematoxylin procedure for roots fixed in formalin-sublimate or in Hellys fluid. Formalin-sublimate fixation required iodization during the staining sequence, but roots fixed in Hellys fluid were best iodized to remove mercurial precipitates before embedding in paraffin. Both methods required treatment with 1% KOH before immersion in the staining solution to remove RNA and produce pale cytoplasm. A third successful method was to postosmicate methacrylate-embedded roots after fixation in Hermanns fluid. Blackened mitochondria were produced by the postosmication and further staining was unnecessary. Fixation in Regauds fluid did not give successful stains in any of the three methods tested. A prefixation treatment in quinone did not aid in obtaining sharply stained mitochondria of roots fixed in Bouins fluid and stained with Heiden-hains iron-hematoxylin.