A few images from today - hand sectioned ivy
Posted: Sun Aug 04, 2019 7:03 pm
Hi all, it's been raining constantly here today so I've been confined to the lab!
I've been taking a few 'quick & thick' sections by hand of some very tough ivy (not the same species as the ivy prepared in my previous post) growing all over a drystone wall at home. This species of ivy, yet to be identified, is very tough and very hard to cut with a razorblade. I'm considering preparing (grossing) some of this one to make slides for comparison to the ivy grossed in my earlier post.
So, I took a few hand sections, necessarily quite thick as this is one tough stem! Looking at the sections, which I stained briefly with Safranin and Alcian-blue, it's easy to see why. This stem is full of hard fibers - sclerified-cells with thick lignified secondary walls, staining pink in the following images. The Xylem are a little disappointing in these images, but the sections are so thick that it was unavoidable I think.
So, a few images; quite dark and heavily-stained compared to the thin microtome-cut sections I make..
The Xylem (I think), with massive fiber-bundles either-end,
Within the cortex are what I think are ducts - with a recognisable pattern of surrounding-cells in a 'ring' almost,
This is I think collenchyma which is reinforcing below the epidermis, but is not totally rigid like lignified fibers and so is able to twist and bend during growth without compromise.
An almost 'glowing' fiber-cap above the blue-stained phloem (I think this is phloem - these sections are pretty difficult to interpre without a very good hard look). To the right of this image is the blurred-outline of a duct within the cortex, to the left is the slightly darker blue cambium and further left the latest (pink) xylem, which looks like fiber rather than vessel-elements.
Now, I referred at the top of this post to the fibers with the term 'massive' - and these two images, the same image only one in mono, help I think to portray this - massive in the sense of bulk rather than sheer dimension, first in somewhat lurid colour,
and in a rather dark and heavy-looking mono,
Those fibers make this a very tough stem indeed - I wonder what the Might-Shandon will make of them!
Finally I've been studying morphology of different types of vascular bundle as related to plant adaptation to habit and habitat and though you may like to see a 'normal' Sunflower-stem vascular bundle, again topped with a large fiber-cap (nowhere-near as tough as the ivy above though). This is a 'closed' vascular bundle in that it has no vascular cambium and is not undergoing any secondary growth - in essence it has 'done expanding'...
This is a fully stained and permanently mounted microtome section cut at about 5µ. The cellular contents have been removed prior to staining and mounting by the application of NaOH (I usually use 6% or thereabouts) to give a clearer representation of cellular arrangement without the need for details of cellular contents. Most often I don't treat sections this way as I usually like to study the cellular contents also - but not in this case. This also makes the staining cleaner, clearer and less lurid.
Here's a stitch of the Sunflower leaf in TS. The obliquely-sectioned leaf veins are seen also - no nice clean parallel-veins to section across as with a typical monocot's leaf!
This is the central 'mid' or 'main' vein of the same leaf. This slide was stained with the excellently-metachromatic Toluidine-blue stain.
Just though a few colourful images would brighten-up this dismally rainy and dark day in the U.K.
Hope you find them interesting. I think I'll go ahead and take some tissue for sections of this big-tough ivy, it has an interesting structure. Also, these images are from this year's stem-growth - the older stem preceding this on the plant shows 'growth rings' from it's perennial growth, last year etc.
I've been taking a few 'quick & thick' sections by hand of some very tough ivy (not the same species as the ivy prepared in my previous post) growing all over a drystone wall at home. This species of ivy, yet to be identified, is very tough and very hard to cut with a razorblade. I'm considering preparing (grossing) some of this one to make slides for comparison to the ivy grossed in my earlier post.
So, I took a few hand sections, necessarily quite thick as this is one tough stem! Looking at the sections, which I stained briefly with Safranin and Alcian-blue, it's easy to see why. This stem is full of hard fibers - sclerified-cells with thick lignified secondary walls, staining pink in the following images. The Xylem are a little disappointing in these images, but the sections are so thick that it was unavoidable I think.
So, a few images; quite dark and heavily-stained compared to the thin microtome-cut sections I make..
The Xylem (I think), with massive fiber-bundles either-end,
Within the cortex are what I think are ducts - with a recognisable pattern of surrounding-cells in a 'ring' almost,
This is I think collenchyma which is reinforcing below the epidermis, but is not totally rigid like lignified fibers and so is able to twist and bend during growth without compromise.
An almost 'glowing' fiber-cap above the blue-stained phloem (I think this is phloem - these sections are pretty difficult to interpre without a very good hard look). To the right of this image is the blurred-outline of a duct within the cortex, to the left is the slightly darker blue cambium and further left the latest (pink) xylem, which looks like fiber rather than vessel-elements.
Now, I referred at the top of this post to the fibers with the term 'massive' - and these two images, the same image only one in mono, help I think to portray this - massive in the sense of bulk rather than sheer dimension, first in somewhat lurid colour,
and in a rather dark and heavy-looking mono,
Those fibers make this a very tough stem indeed - I wonder what the Might-Shandon will make of them!
Finally I've been studying morphology of different types of vascular bundle as related to plant adaptation to habit and habitat and though you may like to see a 'normal' Sunflower-stem vascular bundle, again topped with a large fiber-cap (nowhere-near as tough as the ivy above though). This is a 'closed' vascular bundle in that it has no vascular cambium and is not undergoing any secondary growth - in essence it has 'done expanding'...
This is a fully stained and permanently mounted microtome section cut at about 5µ. The cellular contents have been removed prior to staining and mounting by the application of NaOH (I usually use 6% or thereabouts) to give a clearer representation of cellular arrangement without the need for details of cellular contents. Most often I don't treat sections this way as I usually like to study the cellular contents also - but not in this case. This also makes the staining cleaner, clearer and less lurid.
Here's a stitch of the Sunflower leaf in TS. The obliquely-sectioned leaf veins are seen also - no nice clean parallel-veins to section across as with a typical monocot's leaf!
This is the central 'mid' or 'main' vein of the same leaf. This slide was stained with the excellently-metachromatic Toluidine-blue stain.
Just though a few colourful images would brighten-up this dismally rainy and dark day in the U.K.
Hope you find them interesting. I think I'll go ahead and take some tissue for sections of this big-tough ivy, it has an interesting structure. Also, these images are from this year's stem-growth - the older stem preceding this on the plant shows 'growth rings' from it's perennial growth, last year etc.