why was iodine used to stain onion epidermal cells?

Another less complicated answer is that onions contain small amounts of starch and iodine stains starch very well.

Iodine is used as a mordant, which ability it helps the methylene blue adhere to the particular nucleic acids and phospholipids by using charm (chemotaxis). without the iodine theres a stable probability the methylene blue will run off of the needed organelle without adherence. Im not too optimistic approximately onion cells yet while the cellular wall is made up of a few style of lipid bi-layer then with the utility of the iodine the methylene blue will adhere. wish it helps

There are dozens of dyes you could use to stain onion cell protein. You use iodine because it is super cheap and I doubt your Bio-Lab has more than a few hundred dollars per year budgeted for supplies like that.

yes gud question the

the dyies which have iodine is used cos iodine forms a bond with the lypoproteins so a protein- iodine complex is formed