Dandelion (Taraxacum officinale) Pollen

[ralfwagner]

Hello,

remember last years pollen session? Here is my (perhaps a bit late ) contribution.

The pollen were pretreated with glacial acetic acid / sulfuric acid (acetolysis). This treatment leaves only the outer shell of the pollen and puts the rest away. In this state the pollen are more similar to that state, in which fossil pollen are.

The final observation was done in a drop of Glycerin / water 1:1. Stacking of these very 3D objects is difficult, here are my three best results:

[Charles Krebs]

Ralf,

These are excellent.
As I found out last spring this is an extremely difficult subject to portray due to it's shape and depth.

The pollen were pretreated with glacial acetic acid / sulfuric acid (acetolysis)

One thing I noticed last year was that if I mounted the pollen using microscope immersion oil the yellow color "disappeared" and it was as if I were looking at the shell. But yours look more interesting. Do you think the appearance would be significantly different with your method? I still have some 100% acetic acid left in my darkroom that I used to make stop baths. Could I use that for your clearing method? (If so, what dilution, time might you suggest?)

[ralfwagner]

Charlie,

thank you for your kind comments on both, this one and on the rotifer.

Do you think the appearance would be significantly different with your method?

definitively yes! It is a bit like preparing diatoms with sulfuric acid. Here is the complete instruction:

a) Fix the pollen sample in acetic acid (100%) for at least 1 day.

b) Remove the acetic acid by centrifugation and decanting.

c) Prepare the fresh acetolysis mixture (it is useful only a few hours after mixing) by mixing 9 parts of acetic acid (100%) with one part of concentrated sulfuric acid. Be careful! It can become very hot if too much water is present!

d) Give 4 ml of the acetolysis mixture to your pollen sample from b) and heat in a water bath until the water boils. When the water is boiling immediately remove the pollen sample.

e) Centrifugate and decantate the sample

f) Wash the sample 3 times with aqua dest. by centrifugation and decantation.

g) Give, after the last decantation, 1:1 with water diluted Glycerin to the sample and then watch this under your Mic.

Either in the liqiuds of a) or g) you can store your pollen forever. If you want to mount them use the Glycerin-Gelantin method.


Lit.: Mikrokosmos 44, page 243-249. This is in German only, but a very intersting article about comparing fossil pollen with recent ones.


I'm quite sure you can use the acetic acid from your darkroom.

[bernhardinho]

Dear Ralf

I told you personally and I don't hesitate to repeat it in public: these are some of the best pollen pics I've ever seen. Beautiful!!


So long

Bernhard