> 1. How reliable are chromosome counts, statistically? How many cells do
> you need to count before you are satisfied that you have the right number?
= Some said that the count before 1970s should be recounted due to the old
technique was not good enough. In a normall count, we count from at least 5
good cells. "Good cell" means the cells that their chromosome spread out
clearly. These cell must have their cell wall intact. The number we finally
take is the number from the majority of the cell, not an average.
> 2. Is it possible to have a nuisance cell or two that show a different
> count from others from the same plant? I mean, what do you do if you
> count, say 20 cells with 2n = 40 and one with 2n = 42?
= Yes, it is possible that there are some cell with different chromosome number.
This phenomenon is called "cytochimera or mixoploidy". From your scenario, 2n
= 40 will be the count.
> 3. How easy is it to break a chromosome in the process of performing the
> preparation and root tip crush?
= It is extremly difficult to break a chromosome without crushing the cell
wall.
I am more than happy to entertain your curiosity.
Surawit
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