You could research and learn which stains and what techniques to use, assaying your own plant tissues yourself, and pick up a good used microscope etc. I bet the cost of contracting a professional to do the work for you would cost "in the ballpark" as just doing it yourself. And you would have equipment left over as something to show for your money!

Interesting idea, I think.

Could you alternatively breed your suspected 4N's with known 2N's, giving you hypothetical 3N's which would not be able to breed? If that is so, it would be worth a shot, and possibly take a lot of time.

A microscope that can resolve chromosomes well enough to count will likely cost big $$$$$$$(>50K!). Best bet would be to contact orchid breeders for suggestions.

It's not entirely reliable, but you can get a pretty good idea in many cases just by comparing pollen grain size to that of known related diploids. That can be done with a little stain and a microscope. You can get an idea of pollen viability at the same time.

A microscope of sufficient quality won't be cheap (but it doesn't have to be good enough to resolve chromosomes) but if you intend to do this a lot it might be worth it. If you have just a few to check out, you could check around at your local university, and probably find some one there willing to let you use their microscope.

Kiwinut,

I used a hospital microscope for a decade looking at red blood cells. They are around 7 microns wide and under the scope appear plenty big. I could see plenty of detail using the 1000x oil immersion lens! Plant cells average around 20 microns. Do the math :)

I like the idea of comparing pollen grain sizes too. Very cheap.

I think stomata guard cell size is supposed to be another indicator of poyploidy.

Tetraploid zinnias also have significantly thicker plant hairs. That might be true of other plants.

MM

Plumfan,

I use a fluorescent microscope in my work. The highest mag lens on it is 100x oil immersion, which will not resolve plant chromosomes well (I've tried it). A 1000x lens should do the job, but have you ever priced one? The objectives on my scope run around 5-10K each, although these are from Zeiss which tend to be very expensive. Yikes!

The guard cells are probably your best bet, and tend to work reliably when the plants being compared are closely related, especially if they are siblings.

Kiwinut,

You are right. I now recall that the highest powered objective lens was 100x and the eyepiece was 10x for a total of 1000x. Mine was a binocular lab scope made for CBC differentials and such.

I still recall good detail of all blood cells even at that magnification. It was my job to catch and categorize all manner of unusual cellular inclusions, hence the need for detail.

I suspect that if one had the right stains, he could see a density differential between plant 2n and 4n in nuclear zones. Just my hunch. Specially if you can catch them pulling apart at anaphase (?).

What stains have you tried for chromosomes?

You should be able to see chromosomes with 1000x (100x lens, 10x eye piece, oil immersion). I do this with the grass species I work with. You may not be able to get great resolution, but if you are comparing some knowns, you should get an idea of what is 2n, 4n etc. (as plumfan suggests). The technique may be a challenge, as root tip squashes are the easiest for seeing chromosomes (pollen in orchids is much too small to work with, I imagine).

Thanks for the continued feedback. I'm still here!

--Stitz--