Ordered xylem
This is a polarized light image of the transverse section through the stem at the base of a leaf on Asarum canadense, or wild ginger. The dorsal side is facing up. The wall of the Xylem in the vascular bundle consist of cellulose microfibrils which are formed and remain in an ordered state such that birefringence is observed. 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 under crossed polarizers on a Spencer 42 petrographic microscope with a lambda plate and an original magnification of 430X using a Sony NEX-5N and a Leica MIKAS 1/3X adapter.
Ordered xylem
This is a polarized light image of the transverse section through the stem at the base of a leaf on Asarum canadense, or wild ginger. The dorsal side is facing up. The wall of the Xylem in the vascular bundle consist of cellulose microfibrils which are formed and remain in an ordered state such that birefringence is observed. 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 under crossed polarizers on a Spencer 42 petrographic microscope with a lambda plate and an original magnification of 430X using a Sony NEX-5N and a Leica MIKAS 1/3X adapter.