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How to collect pollen samples?

Posted: Fri Apr 24, 2020 1:37 pm
by gslab
Here in Minnesota USA the trees are just starting to bud, and the air is filled with pollen. So much so that I'm getting air-quality warnings on my phone's weather app every morning. What is the best / easiest way to collect some pollen samples for study? This morning's warning said that Maple, cottonwood, elm poplar and aspen are the culprits.

I've never done anything like this before (my experience is limited to looking at pond water samples in a 1948 AO Spencer model 33) so I don't have any of the chemicals, stains or equipment that some sample collecting techniques require......yet.

Thanks in advance

George in Minneapolis

Re: How to collect pollen samples?

Posted: Fri Apr 24, 2020 2:40 pm
by mrsonchus
Hi, the best way I find is to collect the pollen 'still in it's bag' - i.e. collect an anther - open or closed - with pollen inside - be sure to make a note of which. Also record or image the plant whence the anther (or even whole flower/bud) came for ID if possible.
Alternatively as maybe for tree pollen that's everywhere just collect a little on a brush, finger, leaf - just about anything in fact as the quantity needed is truly tiny - although this method may preclude an (initial at least!) ID of the parent plant.

So, pluck a flower (the anther may be dissected later) and take it home or to your 'cope! Don't wet it as trying to preserve the flower and tissue, just take with you. Choices of any treatment or mount/observation methods will then be available to you.

In my recent post I give examples of simply adding a tiny amount of pollen to pre-heated and molten glycerin-jelly before coverslipping and setting. A simple water mount is also pretty good, although pollen shapes may vary (e.g. from welling with water or shrivelling with alcohol) when mounted, essential taxonomic detail will very likely be preserved, such as surface type, number and position of 'pores' or 'colpi' (sing colpus), through which pollen tubes emerge when the pollen germinates upon a receptive stigmatic surface. Size of grain is for the above reasons often an unreliable character although huge differences of grain sizes that have a close overall similarity otherwise, may be useful for elimination perhaps at the genus or family levels.....

Pollen is easily 'handled' with a couple of fine paintbrushes and/or needles (I mount very fine acupuncture needles in pencils - very useful), but a stereo microscope will be needed for any complicated mounts or dissections.

Hope this helps - go-get those grains! :D

Re: How to collect pollen samples?

Posted: Sat Apr 25, 2020 12:11 pm
by gslab
Yesterday I let a clean slide sit on the roof of my car for about 8 hours. I had a few different pollen grains to investigate. They were very small. The cars around here are covered with pollen. I wonder if there is a way to get it from the cars to a clean slide. It's adhered to the body work pretty well.