Can I use a basic compound microscope to analyze the ploidy of plant chromosomes?

Question

So, I'm not really any kind of trained botanist. But I do have two things: some dandelion seeds from France, and, collecting dust in my garage along with related accessories, this thing.

Normally, the dandelions growing in an American yard are apomictic triploids, but in Europe there's both triploids and sexual diploids, the latter getting even more common the further south. I'm assuming that, because these French seeds are a specific common cultivar (Vert de Montmagny), that regular sexual selection was used in breeding it, making it a diploid. But I don't know who to ask to confirm this so I may as well do some testing. If it's a diploid, maybe I can do some breeding of my own?

But I don't even know the first step. Are there some parts of a plant that I'll have an easier time finding chromosomes in? What do I put them in to express their DNA and what do they best stain in? Would I even be able to discern the different chromosome shapes without training? I've heard the standard science project way to extract DNA (dish soap, salt, alcohol) damages the chromosomes so that you wouldn't really find them in a microscope; if true I hope there's another way.

Answer 1

If you want mitotic chromosomes then you want to look at apical meristems — probably the primary root from germinating seedlings will be easiest. Apical meristems are at the growing tips of roots (and shoots) and contain regions of rapidly dividing cells. Since you can only see chromosomes as separate bodies when they are condensed for cell division this increases your chances of visualizing chromosomes.

However, you will need to stain the roots to visualize the chromatin (material that makes up chromosomes).

This paper has a protocol for staining dandelion root tips, but I don't know whether you can obtain all the necessary compounds. However, colchicine and para-dichlorobenzene probably aren't really necessary (they will increase the number of cells in mitosis) and are toxic so best to avoid those steps anyway.

Note, it looks like you would also need a 100x oil immersion lens, which doesn't look like it comes with the microscope you listed.

You may also find this paper useful as a starting point for making "homemade" chromosome stains.

Good luck!