Spiral xylem wall
This is a transverse section through the leaf near the stem on Asarum canadense, or wild ginger. The section shows a longitudinal view of the xylem. Note that the cellulose making up the wall forms a spiral. Presumably this is to add flexibility to the tube. Imaging with polarized light helps to confirm this is indeed the xylem. The deep red stained features are cell nuclei which are prefferentially stained by the Safranin-O. Specimen collected along the Dowagiac River, 25 May 2015.
The protocol was as follows. Specimens fixed in FAA (formaldehyde, acetic acid, ethanol) 48 hr. Dehydrated in IPA at 35, 50, 70, 85, 91, 95, 99 %. Infiltrated with paraplast saturated xylene 48 hr followed by 3 Paraplast baths prior to embedding in Paraplast. Sectioned 7 um thick on a Spencer 820 microtome. Cleared in xylene, 5 min, 2X. Rehydrated in 99, 95, 80, 70 %IPA. Stained in Johansen's Safranin-O, Fast Green (2 hours in Safranin-O, 7-15 sec. in fast green). Cleared 2 X in xylene 10 min each and mounted with DPEX.
Photographed in bright field on a Nikon MS inverted microscope at 400X original magnification using a Sony NEX-5N and a Leica MIKAS 1/3X adapter.
Spiral xylem wall
This is a transverse section through the leaf near the stem on Asarum canadense, or wild ginger. The section shows a longitudinal view of the xylem. Note that the cellulose making up the wall forms a spiral. Presumably this is to add flexibility to the tube. Imaging with polarized light helps to confirm this is indeed the xylem. The deep red stained features are cell nuclei which are prefferentially stained by the Safranin-O. Specimen collected along the Dowagiac River, 25 May 2015.
The protocol was as follows. Specimens fixed in FAA (formaldehyde, acetic acid, ethanol) 48 hr. Dehydrated in IPA at 35, 50, 70, 85, 91, 95, 99 %. Infiltrated with paraplast saturated xylene 48 hr followed by 3 Paraplast baths prior to embedding in Paraplast. Sectioned 7 um thick on a Spencer 820 microtome. Cleared in xylene, 5 min, 2X. Rehydrated in 99, 95, 80, 70 %IPA. Stained in Johansen's Safranin-O, Fast Green (2 hours in Safranin-O, 7-15 sec. in fast green). Cleared 2 X in xylene 10 min each and mounted with DPEX.
Photographed in bright field on a Nikon MS inverted microscope at 400X original magnification using a Sony NEX-5N and a Leica MIKAS 1/3X adapter.