Are those little green blobs just green blobs?

[Roy]

Not the best photo in the world but I think it's good enough to illustrate just how much internal structure a three week old Ferrocactus fordii has developed. The section is just over 2.25mm wide
[attachment 2140 ff.jpg]

[Roy]

At two weeks old this Echinocereus does not seem to be much more than a skin and a group of cells.[attachment 2141 sl.jpg]

[Colin Walker]

Hi Roy,

This is an excellent anatomical section. Now, can you name all the tissues and cell types shown in your section? This could be the start of another OU-style lecture, so beware of posting such stuff here without explanation!!!!!!!!!!!!!

[Tom J]

Fascinating!

Tom

[Roy]

Don't be daft Colin of course I can't any assistance would be welcome.
I'm just very inquisitive I leave the technical bit to you guys :-)))))))
Ps just shows what I get up to when it's a miserable wet Saturday afternoon and there's nothing on the telly.

[Julie]

Hehe Great photos Roy! Amazing how the Ferrocactus has developed so much internal order at such a tender age.

My meloformis is showing some white in the ribs where the skin isn't continuous any more, so I think I might be able to add some more chopped-up pics tomorrow. She is looking less and less happy with time, despite being moved to a warmer spot.

I'll ask her if she will donate her body to science. I'm curious if she has the same inner cavity as the worse-for-wear obesa a while back.

Btw what sort of knife do you use? I always thought Stanley was the sharpest, but mine was not so sharp as I thought when I chopped Nelii, and it was a fairly new blade. Might borrow the fancy tomato knife.

[Roy]

Hi Julie,
I use scalpel blades that I get from the local drawing and craft shop.

[Colin Walker]

Hi Roy,

I'd be happy to oblige but would need to capture the images and add labels, and I'm not quite up to speed on doing that kind of stuff from where I am, i.e. at home.

Just for the first seedling:

You should be able to clearly see two parallel lines of cells radiating upwards from the base - these are the start of the vascular tissue, the plumbing that transports water and materials around the plant.

Surrounding these are nearly spherical not so green cells - these are parenchyma that store water.

Outer green cells contain chlorophyll where light energy is captured that drives all the other activities within the plant.

Not so easy to discern is a small dense mass of cells centre near the very top - this is the meristem where new cells develop.

How's that for starters even without an interactive whiteboard?

[Colin Walker]

Hi again Roy,

Well if the weather's still naff, why not try cutting up (i.e. dissecting) some other plants? You could try looking for differences between dicots (e.g. cacti) and dare I mention the infamous monocots (e.g. aloes)?

Try cross sections (as opposed to the vertical sections through the cactus seedlings) to see if you can find the important differences between these two main plant groups.

You might also like to try sections through leaves. There you might find the breathing holes (stomata) through which gases are exchanged.

[Victoria]

Ah brings back memories of my OU course last year which had a section on plant physiology.

One method to examine the structure of stomata that I remember from college is to paint a layer of PVA glue on the underside of a leaf, wait for it to dry then peel off. Examine under the microscope and by playing with the contrast you can get a view of the imprint of the stoma.

Personally I don't like stomata, they look like little mouths or eyes and it freaks me out! I'm odd like that.

Really must get my microscope out on these wet weekends and do some photos.