Spiral Vessels from an Orchid -- Two pictures added

Images made through a microscope. All subject types.

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Cactusdave
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Spiral Vessels from an Orchid -- Two pictures added

Post by Cactusdave »

An old paper-covered slide, marked 'Spiral vessels from Orchis (Saccalabium)' in beautiful Victorian copperplate writing. No makers name.

Quote:

'Vessel elements are the building blocks of vessels, which constitute the major part of the water transporting system in the plants where they occur. Vessels form an efficient system for transporting water (including necessary minerals) from the root to the leaves and other parts of the plant.
In secondary xylem, a vessel element originates from a fusiform initial in the cambium, at maturity the protoplast dies and disappears, but the lignified cell walls persist. It may be seen as a dead cell, which still has a function, and is still being protected by surrounding living cells.
The cell wall is strongly lignified. At both ends there are openings that connect the individual vessel elements. These are called perforations or perforation plates. These perforations may have a variety of shapes: the most common are the simple perforation (a simple opening) and the scalariform perforation (several elongated openings on top of each other in a ladder-like design). Other types include the foraminate perforation plate (several round openings) and reticulate perforation plate (net-like pattern, with many openings). The side walls will have pits, and may have spiral thickenings.'

http://en.wikipedia.org/wiki/Vessel_element

Saccalabium is a Genus of Tropical orchids, Charles Darwin was interested in the arrangement of the spiral vessel elements in the developing flower of the Orchid, and discussed the current theory of the time that the organisation of these vessels might help shed light on the homologies between the parts of flowers of different plant families. http://www.darwinproject.ac.uk/entry-5097

This slide was imaged with a Nikon Diaphot microscope, using a LWD 0.55 phase/DIC condener and X20 0.40 Plan DIC objective. The method of illumination was polarisation produced by dialing the upper and lower Wollaston prisms out of the light path, but retaining the upper polariser, moveable 1/4 wave plate and lower analyser. In addition the Ph2 phase annulus was included in the light path to provide an element of oblique lighting to the rather 'flat' polar image. The camera was a Canon 40D mounted in the front SLR port and total magnification was X50.

The image is formed by stitching the outputs of two image stacks, using Microsoft ICE. In total 25 images were collected.

Image

A larger version of the image is located here. http://photosynth.net/view.aspx?cid=77a ... c729836faf

The background was set to black in Photoshop.

Original red background. Stacking with Zerene DMap

Image


The structure of the spiral bundles of birefringent fibrils in the wall of the vessel is fascinating. If you try to follow it in 3D, it reminds me very much of a Moebius strip
:shock: http://en.wikipedia.org/wiki/M%C3%B6bius_strip
Last edited by Cactusdave on Wed Dec 21, 2011 10:14 am, edited 2 times in total.
Leitz Ortholux 1, Zeiss standard, Nikon Diaphot inverted, Canon photographic gear

Cactusdave
Posts: 1631
Joined: Tue Jun 09, 2009 12:40 pm
Location: Bromley, Kent, UK

Post by Cactusdave »

Unstacked single polarisation image of the same spiral vessel without 1/4 wave plate and with X10 Plan DIC objective rather than X20. Cropped a bit from the original.

Image


Similar, but using the same objective in DIC mode.


Image
Leitz Ortholux 1, Zeiss standard, Nikon Diaphot inverted, Canon photographic gear

Mitch640
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Post by Mitch640 »

Wonderful images Dave. Very Abstract.

RogelioMoreno
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Post by RogelioMoreno »

Very nice.

Rogelio

Cactusdave
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Post by Cactusdave »

Thanks Mitch and Regelio.

I have had trouble understanding how these spiral-walled vessel elements come together to make functional interconnecting tubes in the plant. The examples on this slide appear to have been dissected out of the plant tissue, perhaps after some form of maceration. If I read the literature correctly, these elements join end to end with special joining structures called sieve plates. If we have any botanists among our contributors, perhaps they could confirm this.
Leitz Ortholux 1, Zeiss standard, Nikon Diaphot inverted, Canon photographic gear

Ferry
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Post by Ferry »

Well, that is really beautiful. Amazing.

Cactusdave
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Location: Bromley, Kent, UK

Post by Cactusdave »

Thanks Ferry, very much appreciated. I have taken some additional pictures of this subject using the Lomo X30 0.90 water immersion lens, which gave excellent results. I'll post a couple of additional pictures taken with this lens at some point. They'll need to be viewed hosted on Photosynth though, as they are big stitches.
Leitz Ortholux 1, Zeiss standard, Nikon Diaphot inverted, Canon photographic gear

Cactusdave
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Joined: Tue Jun 09, 2009 12:40 pm
Location: Bromley, Kent, UK

Post by Cactusdave »

As promised, a couple of images of this slide using the Lomo 30X 0.90 EAF water immersion flat field achromat. This lens is short and needs a 12mm extender to be parfocal with DIN standard objectives. It is well regarded for sharpness and bright image. I have used it on a Zeiss Standard, but this was my first experience on the Nikon Diaphot. For a discussion of water immersion objectives see here: http://www.microscopy-uk.org.uk/mag/art ... vwimm.html

The lens worked well giving a sharp, bright image. It produced a good DIC image with the Diaphot 40X prism, though there was the expected unevenness of illumination over the extended field needed for stitched images, and some chromatic aberration from the mismatched optics. The 30X magnification was good for this subject and the resolution of the Lomo lens seemed superior to the Nikon X20 Plan DIC.

First a large stitch of 35 unstacked images showing the original spiral vessel and a couple of others with the more typical fusiform ( cigar-shaped) appearance. Illumination was by polarisation. Image

The uneven background has been homogenised to a neutral grey in Photoshop. A large 260 Megapixel version is here http://photosynth.net/view.aspx?cid=ed7 ... f4ca23a85c

The second image is with the x40 DIC prism and is a stitch of 16 unstacked images. The 1/4 wave plate ( compensator) is inserted to give a false colour image. The uneven background colour has been left as photographed.

Image

A larger 46 Megapixel version is here;
http://photosynth.net/view.aspx?cid=a90 ... bf5b1184e6
Leitz Ortholux 1, Zeiss standard, Nikon Diaphot inverted, Canon photographic gear

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