If your observation had not been restricted to the tip of the onion root how would the results be different?

The majority of the time, the cells are present in the interphase stage. The cells, which were proliferating were growing. The majority of the other cells, that is, apart from the cells at the root tips remain in the interphase stage. Thus, if one had been observing at different parts, they probably would have all been in interphase.

Interphase signifies the stages of the cell apart from mitosis. At the time of interphase, all the cellular organelles get double in number, the synthesis of proteins takes place and the DNA duplicates. The chromosomes are not visible and the DNA seems to be present in the form of uncoiled chromatin.