I wasn't planning on working with colchicine, but it is good to know the risks and dangers. If Oryzaline is easier to obtain and less toxic, than I would like to try to create some tetraploids in the future. It is a subject that fascinates me. And I will be very careful with anything that can disrupt natural endocrine or hormone concentrations.
In many books it is mentioned that tetraploidity is so common among plants though, that even without these methods it should be quite likely for you to come across a natural occurring tetraploid sport or seedling in your lifetime career of gardening. I would like to be alert at that time and not miss those occasions when they occur. That is why I was looking for an easy way to verify if some plant may be tetraploid.
Of course in theory it should become clear as well eventually out of the crosses made with that plant. But that is a long method. Triploids could turn up in the crosses.
But thank you very much for pointing out this method. I have made my first leaf impressions and slides, and the results are pretty unexpected and lead me to want to make many more leaf impressions and leaf stomata counts.
I bought two kinds of colorless nail polish, of which one is clearly superior to the other for making leaf prints.
The magnification on my microscope is good enough, but it takes quite a lot of fiddling with the diaphragm in order to get a clear focused picture that is good enough to do the count.
The part of the leaf you look at makes quite a lot of difference, there are area's with very few leaf stomata and areas that are quite packed with them.
I decided to compare the areas that were maximally packed with them, and here are the first pictures:
I have used three plants: a mini pitanga, with very small leaves. A 'Big Red' pitanga, which has very large leaves and supposedly very large fruit. And then my own supposed tetraploid that has unusual vigor and very large leaves.
From the study I would have suspected that my own suspected tetraploid plant would have the smallest number of leaf stomata per area, and the Mini pitanga and Big Red would have more it less the same amount...
Here are the pictures:
Mini Pitanga: counted leaf stomata: 48
Mini Pitanga: counted leaf stomata: 53
Big Red Pitanga: counted leaf stomata: 35
Suspected Tetraploid: counted leaf stomata: 68
Suspected Tetraploid: counted leaf stomata: 60
From these results I should deduce that my suspected tetraploid is not at all a tetraploid, but just a very vigorous grower with large leaves, since it has an even higher count of leaf stomata than my control Pitanga- the mini Pitanga.
In the process though, it looks like the Big Red Pitanga could be a genuine tetraploid. I got seeds from this one from Cassio, and it would be interesting to make crosses with it in the future to see if any triploids turn up.
In the coming weeks I'll do some more counts of other different pitanga's I have and hope to get some more data and a sort of baseline number of leaf stomata.
Thanks again for pointing me in this direction, I'm having a lot of fun doing this!