Foliose lichen thallus
Polarized light (crossed polarizers) micrograph of a cross section of a foliose lichen found on a dead tree. Specimen from the edge of the Dowagiac River (5/15). The bark is to the right and the dorsal surface to the left. Lichen is a combination of a fungus and an algae (or cyanobacteria). The algal constituent does not show optical activity, however, the fungal hyphae show what appears birefringent crystalline material likely calcium oxalate. A bright field image is at: www.flickr.com/photos/14643312@N02/17599529683. The source specimen is shown in: www.flickr.com/photos/14643312@N02/17758847712/ and www.flickr.com/photos/14643312@N02/17573214550.
The following protocol is largely based on Chamberlain, "Methods in Plant Histology, 5th ed., 1905. Fixed 24 hours in aqueous chromic acid-acetic acid (3.7 g potassium dichromate/l + 10 ml glacial acetic acid/l). (The substation of potassium dichromate for chromic acid based on equivalent chromate conc. is reported to work as long as the pH is less than 3.4). Washed 24 hours in flowing water. Dehydrated in 10, 35, 50, 75, 85, 95, 99 % IPA in water, 6 hours each min. Infiltrated in xylene saturated with Paraplast for 2 days, followed by 2 changes of melted Praplast for 2 hours each. Embedded in Paraplast. Sectioned on a Spencer 820 microtome at 11 micron. Cleared in Xylene 2X, 10 min each. Rehydrated 99 (10 min), 95, 85, 70 % IPA, 2 min. each. Stained Gill's Hematoxylin 10 sec. Washed 3 min running water. Blued 0.05 % lithium carbonate 3 s. Water rinse 1 min. Stained 1 % aq. Erythrosin-B 2 min. Dehydrated 99 % IPA 2 min. Cleared 2X xyene 5 min each. Mounted with DEPEX. Lichen are reported to be difficult to adhere to the slide, however, white this protocol, I had no issues with the tissue coming off the slide.
Photographed on a Spencer 42 petrographic polarizing microscope under crossed polarizers using an original magnification of 430X, using a Sony NEX 5N with a Leica MIKAS 1/3X adapter.
Foliose lichen thallus
Polarized light (crossed polarizers) micrograph of a cross section of a foliose lichen found on a dead tree. Specimen from the edge of the Dowagiac River (5/15). The bark is to the right and the dorsal surface to the left. Lichen is a combination of a fungus and an algae (or cyanobacteria). The algal constituent does not show optical activity, however, the fungal hyphae show what appears birefringent crystalline material likely calcium oxalate. A bright field image is at: www.flickr.com/photos/14643312@N02/17599529683. The source specimen is shown in: www.flickr.com/photos/14643312@N02/17758847712/ and www.flickr.com/photos/14643312@N02/17573214550.
The following protocol is largely based on Chamberlain, "Methods in Plant Histology, 5th ed., 1905. Fixed 24 hours in aqueous chromic acid-acetic acid (3.7 g potassium dichromate/l + 10 ml glacial acetic acid/l). (The substation of potassium dichromate for chromic acid based on equivalent chromate conc. is reported to work as long as the pH is less than 3.4). Washed 24 hours in flowing water. Dehydrated in 10, 35, 50, 75, 85, 95, 99 % IPA in water, 6 hours each min. Infiltrated in xylene saturated with Paraplast for 2 days, followed by 2 changes of melted Praplast for 2 hours each. Embedded in Paraplast. Sectioned on a Spencer 820 microtome at 11 micron. Cleared in Xylene 2X, 10 min each. Rehydrated 99 (10 min), 95, 85, 70 % IPA, 2 min. each. Stained Gill's Hematoxylin 10 sec. Washed 3 min running water. Blued 0.05 % lithium carbonate 3 s. Water rinse 1 min. Stained 1 % aq. Erythrosin-B 2 min. Dehydrated 99 % IPA 2 min. Cleared 2X xyene 5 min each. Mounted with DEPEX. Lichen are reported to be difficult to adhere to the slide, however, white this protocol, I had no issues with the tissue coming off the slide.
Photographed on a Spencer 42 petrographic polarizing microscope under crossed polarizers using an original magnification of 430X, using a Sony NEX 5N with a Leica MIKAS 1/3X adapter.