Equisetum arvense
This is a transverse section through the stem of a Horse Hair (Equisetum arvense.) The previous photo shows the multi-layer structure of the internode region of the stem. This is a detail of a vascular bundle in the middle layer. Specimen collected along the Dowagiac River, 25 May 2015. In retrospect, the stem was not perfectly straight in the paraffin block and it was too thin.
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 (24 hours in Safranin-O, 15 sec. in fast green). Cleared 2 X in xylene 10 min each and mounted with DPEX.
Photographed in bright field on a Spencer 42 petrographic microscope at original magnification of 200X using a Sony NEX-5N and a Leica MIKAS 1/3X adapter.
Equisetum arvense
This is a transverse section through the stem of a Horse Hair (Equisetum arvense.) The previous photo shows the multi-layer structure of the internode region of the stem. This is a detail of a vascular bundle in the middle layer. Specimen collected along the Dowagiac River, 25 May 2015. In retrospect, the stem was not perfectly straight in the paraffin block and it was too thin.
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 (24 hours in Safranin-O, 15 sec. in fast green). Cleared 2 X in xylene 10 min each and mounted with DPEX.
Photographed in bright field on a Spencer 42 petrographic microscope at original magnification of 200X using a Sony NEX-5N and a Leica MIKAS 1/3X adapter.