BIOLOGY. What other parts of an onion (besides root tip) might be used to study mitosis?

I go to a very small school, and my bio lab (for my online bio cl) required me to use a microscope on whitefish embryo's and onion root tips. I don't have the slides, nor do I have a working microscope. Sad I know. ... Please answer these questions as if you've already looked at both slides through a microscope. Thank you so much!! ALSO, another question, what is the difference in cells BEHIND root tip, compared to those IN the tip. .... I'd really like to answer these myself, I love bio, but our school of 30 students usually don't have the lab materials I need. :( ... thanks a lot to anyone who answers this for me. ^_^