Epodea plant cells the chloroplasts 'retreated'

[nobahar]

Hello!
I performed a quick practical today using light microscopes. When looking at Epodea plant cells the chloroplasts 'retreated' to the edge of the cell; the vacuoles weren't particularly large and so didn't appear to be 'pushing' the chloroplasts an awful lot. Also, the chloroplasts at the egde seemed to 'circle' the cell (the direction differed amongst cells). Can someone explain the choroplasts behaviour? Is it possible that they were just other 'organisms' (the question in th epractical seemed to imply that they were chloroplasts)? Any response would be appreciated.
Thanks!

 

[chemisttree]

http://jeb.biologists.org/cgi/content/full/206/12/1963

 

[nobahar]

Thanks for the link, that's just what I was looking for!
Much appreciated; and there's plenty to read...