Rosa sp.

Many thanks to Tatcher a Hainu@Flickr (aka Eckhard Völcker) of Berlin, Germany, for submitting today’s micrograph via the Botany Photo of the Day Flickr Pool (original image). To view more of Eckhard’s micrography work, visit his site titled Wunderkanone (hint: click on Pflanzen for vascular plant imagery). You can also see a small gallery of his work via Labgrab.

As Eckhard explains in the comments accompanying his photograph, this is a 10x magnification of a cross-sectioned pedicel of a rose. His technique? A microtome, or a machine for slicing tissue (think deli meat slicer, but much smaller), is used to make the even cross-section. The sections are then mounted on microscope slides and stained with a dye (or dyes). Different tissues react to different dyes. Expert (and careful) technique can produce a range of colours, as seen here.

Working from the outside of the pedicel inwards: a red-stained cuticle is subtended by a single cell layer thick epidermis. The next dozen or so cell layers form a band called the cortex, consisting of the outermost ~4 cell thick angular collenchyma (provides supportive structure for new growth) and large, undifferentiated parenchyma. The band of colourful vascular bundles (or water and nutrient transport tissues) are next. At the bottom of this micrograph is another grouping of parenchyma, forming the pith.

Each vascular bundle is surrounded by yellow-stained cells that I believe are sclerified parenchyma; these have developed to provide support and protection to the vascular tissue. The orange-red stained cells are a bundle cap of fibres associated with the nutrient-carrying phloem tissue, which consists of the small densely-packed green-stained cells immediately below. The medium-sized bluish-stained cells toward the inside of each vascular bundle form the tissue called xylem, often associated with water transport (but also carry some nutrients). Between the xylem and phloem tissue is a thin band of vascular cambium, a meristematic (undifferentiated cell generating) tissue that will produce additional xylem and phloem with time.

By the way, if I’m wrong about anything, I’d welcome any corrections — I’m not a plant anatomist, though had I been able to section and stain tissue with the skill that Eckhard has, perhaps I would’ve taken a few more courses on the topic.

Photography resource link: Local readers will likely be familiar with his work, but if you’ve never seen the photography of Chris Harris (photo gallery), you’re in for a treat.

Rosa sp.

11 responses to “Rosa sp.”

  1. Joe

    I may be mistaken as well, but I think that the xylem cells are the darker red cells to the inside of the phloem and the vascular cambium to which you refer. I believe that the yellow-stained cells surrounding the vascular bundle may be collenchyma? I welcome corrections as well….

  2. Earl Blackstock

    Hey Daniel,
    Your ability to explain complex subject material and make it simple and understandable is appreciated. Cheers!

  3. Vicki

    This is such a walk down memory lane, and a delightful surprise. Thank you!!!!!!!

  4. Jamie

    This is fantastic! Both the photography and your
    explanation.

  5. Elizabeth Barrow

    Thank you very much — this was wonderful!

  6. jane

    You may be mistaken. This appears to be a close-up of the mosaic at the Galla Placidia in Ravenna, Italy!

  7. CherriesWalks

    Nature is totally cool!

  8. Brian

    Beautifully done piece of work. When I studied botany way back somewhere in the early 14th century, mere students were of course not allowed to use expensive playthings like microtomes, so we used common razor blades, and trust me, you do not get this sort of result, and if you’re not careful you end up with bits of human tissue alongside your plant cross sections.
    I can’t remember enough of all the learned terminology to be able to say whether any mistakes slipped into Daniel’s post, except what is probably a typo: I would think the magnification here is at least 100x and not 10x as posted.

  9. elizabeth a airhart

    science is an art -reminds me of
    pochoir prints from eugene grasset perhaps
    or a fine tiffney window very art deco
    thank you tis a lot of work art can be that way
    chris harris -thank you daniel he is just
    very good i am on newsletter list bon bon

  10. Sara

    second vote to Jane’s comment.
    It looks like an amazing art display, composed of peas and beans, mimicking peacock feathers on a float for the Pasadena (CA) Rose Parade.
    great stuff.

  11. Alexander Jablanczy

    Is meristem in vascular plants analogous to stem cells in animals? ie a pluripotent cell much as chlorophyll to heme? Of course at a different level. Cell differentiation and apoptosis vs.
    O2 and CO2 transport.

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