The Fixing and Staining of Liriodendron Tulepifera Root Tips and their Mycorrehizal Fungus

Abstract

Root tips of L. tulipifera forming an endotrophic mycorrhiza with a fungus of the Mycelium radicis group, were subjected to several different fixations in which the actions of cationic and anionic Cr were compared. Anionic Cr in the form of chromic acid was combined with several substituted benzene compounds while cationic Cr in the form of chromic sulfate (Cr2(SO4)3.- 15H2O) in 4% formaldehyde was used with the same ring compounds. In addition, several fixatives not containing Cr were tested. 5% Cr2(SO4)3-15H2O in 4% formaldehyde or in 1% osmic acid with saturated aqueous salicylic and/or picric acid preserved the histological and cyto-logical details of the mycorrhiza, as was clearly demonstrated when followed by staining in 3% acetic acid saturated with orseillin BB and counterstained with 1% crystal violet in clove oil. 2% FeCl3 in 4% formaldehyde showed the relationship of the tannin contents of the cells to the invading hyphae when followed by suitable staining. Cationic Cr appeared to be superior to anionic Cr in preserving cell walls as well as the general histo-logic features of the material investigated.