Some Timothy Hay Structures: BUY WHY?

About the shape and function of different specimens
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Some Timothy Hay Structures: BUY WHY?

#1 Post by linuxusr » Mon Oct 11, 2021 1:43 am

Recently I pipetted from my infusion jar (timothy hay) and found a helical coil! Not exactly commonplace. In “Identification help” I asked: "Plant or Alga?"

Our resident botanist, mrsonchus, gave a fascinating explanation, including an excellent graphic from www.jstor.org

More on that later.

First, I want to explain why it makes sense to learn some basic structures of timothy hay (or any other plant material used to infuse).
Assume that a sub-set of specimens that you observe from an infusion are either dead or immobile. Given that plant parts also have micro dimensions, how do you know when you are looking at a specimen generated from the infusion versus a plant part from the infused material? With some obvious exceptions, the answer is that: You Don’t Know.

It makes sense, therefore, to take a micro inventory of your infusion material to distinguish it from the specimens you seek. And those parts, since many are micro parts, are intrinsically interesting anyway. And this is what I did. Of course, the timothy hay I used was harvested, so it didn’t have the roots. But it did have stems, seeds, and seed bearing terminal branches (don’t know the name). To my surprise, after a simple dissection and viewing at 100xTM, I was able to find the same helical coil, albeit in its original state, within the stem! (Upcoming)

In my original photo, the same one that I posted to “Identification help,” you can see the helical coil disassociated from the stem and not in its natural state. Being submerged in water and not in the air, the timothy hay stem was in the process of entropy and decay and the coil separated out. And there’s a reason that that coil did not undergo the same rate of entropy as the stem, as will be indicated below when the function of that structure will be described as well as the composition of that structure as being lignified.

Photo ONE: https://imgur.com/NnaRhbR

But what is that helical coil?

Let’s start with two googled definitions:

a. xylem: the vascular tissue in plants which conducts water and dissolved nutrients upwards from the root and also helps to form the woody element of the stem.
b. lignin: a complex organic polymer deposited in the cell walls of many plants, making them rigid and woody.

Here I will give some background, paraphrasing from mrsonchus, her responses to my original post:

In Photo ONE you are seeing a lignified structural element of the secondary wall, primary xylem (italics mine). Lignin is a hard substance used as reinforcement in the conducting tubes (xylem). These thickening spirals and helices give the support necessary to keep the vessels open like the cartilage in our windpipes which are rings but not spirals.

However, the lignified xylem vessel element that you see in Photo ONE is an example of one point in time of its growth phase, in other words, these spirals and helices change their conformation as the stem and xylem growth proceed. Here I will directly quote mrsonchus:


“Primary thickening occurs whilst a (part of a) plant is still growing, expanding and certainly lengthening in the case of stems. The lignification is needed 'from the off,' as it were, but must be capable, when added at this primary stage, of expanding along with the vessels' cell walls - hence primary lignification tends to be either discrete rings, spirals or helices, which will be able to move along with a lengthening cell-wall, similar to the spirals in those stretchy tubes a vacuum cleaner may have for it's flexible and stretchable tool-extensions. Maybe a case of similar form/functionality....

Secondary reinforcement, again with lignin, is added after a cell has attained it's full size/length etc, and so doesn't need to be of a form that allows stretching - the upshot of which 'secondary' thickening takes a more solid form, in fact there's a progression of the form-function example observable in a section through the right orientation of a stem's vascular bundle - LS shows this better than TS usually. Ultimately the lignification may well be almost a complete 'skin' around a vessel - very strong, unable to stretch without ruin, and definitely able to hold-open the vessel 'tube'... In fact helices can be found at the crossover of primary and secondary growth - so could be either, but I think more likely primary - contradicting my earlier response....

'Primary' and 'Secondary' growth is NOT the same meaning as 'Primary' and 'Secondary' cell-walls - both of which are very important to understand if the inner workings of plants are to be uncovered!”

The following chart, which mrsonchus downloaded from www.jstor.org gives a clear depiction of these growth stages from left to right, A,B,C,D, and E.

Chart: Image

In Photo ONE, you are looking at D, the final stage in secondary wall thickening. Notice that the spiral (not the helix) previously mentioned, is in the second graphic of the Proto Xylem, before A.

In Photo TWO following, taken from one of my timothy hay infusions, you are looking at the lower half of B, Primary wall:

Photo TWO: https://imgur.com/JfpFCi9

Photo THREE: In this photo, from another infusion, you are looking at several lignified structures that have disassociated from the xylem.
Interestingly, you can see, simulataneously, the progression of both C and D, secondary wall thickenings. Maybe mrsonchus can explain why both stages co-exist.

Photo THREE: https://imgur.com/FmaxgL7

Now I want to proceed to my dissection of a dry timothy hay stem in which, I think, I have discovered the same lignified structure. As I proceed with this description from the outside of the stem to the inside, recognize that I do not have knowledge of botany except from what I am learning from mrsonchus, so that my descriptions will not be using correct botanical nomenclature. Rather, I will be describing my observations as an amateur microscopist, and adding, where appropriate what I have learned from mrsonchus.

To make Photo FOUR, I cut a short piece of timothy hay stem, then with a scalpel cut it lengthwise, and viewed it at 100x TM. What you are seeing in Photo FOUR is the dorsal or ventral side of one-half of a timothy hay stem cut longitudinally, details to follow:

Photo FOUR:

https://imgur.com/5bWEzYs

First, observe the lightly colored longitudinal “channels.” Looking down through the eyetube, this “channel” appears two-dimensional but from observing same in the dissection, it is convex. Further, these channels surround the circumference of the stem, more or less equidistantly. In this microscopial view, two more channels are hidden because they are out of the objective’s focal plane. I am estimating six to eight of these “channels” extending longitudinally around the circumference. Notice also the rectangular cells and cell walls.

Here comes the surprise, an “Aha” moment for me. Have you seen the popular optical illusions where when you view the image, you see A. Then, after an unconscious perceptual adjustment, you see B? Once you see A and B, you can flip back and forth between A and B. Some people see A but never see B.

It took me a while, while looking discretely at the cellular structures within the channel, “A,” before I suddenly saw from a different visual perspective “B!” And what is B? B, here, are tightly coiled helical lignified structures corresponding to D in the diagram, last stage of secondary wall thickening! Do you see them? I propose that in each of these “channels” which are partially spherical (convex), are embedded the lignified structures. Here, mrsonchus, or another botanist member, will need to elucidate.

Lastly, in Photo Five, I show a seed.

Photo Five:


https://imgur.com/6aNBn0P


Here, in the tendrils, you can see some purple colored objects. I have seen these in various plant leaves and I think they are involved in photosynthesis. Can anyone shed light on that? And, if so, why would they be in the tendrils, and are these tendrils a defensive mechanism?
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