Re: Why don't plant cells need centrioles?

While there is not one definitive answer to your question there are 
several possibilities for why plant cells do not need centrioles or, more 
correctly, can survive without centrioles.  Most Introductory Biology 
textbooks seem to emphasize the role that centrioles play in spindle 
apparatus formation during mitosis and meiosis.  In plant cells the polar 
ends of the spindle apparatus appear to congregate in a protein rich area 
which may substitute for the function of the centrioles in animals during 
cell division.  A second function of centrioles is in the development of 
cilia and flagellae formation in motile animal cells.  Since most plants 
do not possess motile cells one could argue that there's no reason for 
the presence of centrioles.  There are many locations on the Web that 
address the subject of centrioles and their presence or absence in plant 
and animal cells and I have enclosed three of the site addresses below.  
Good luck with your AP Biology.
 http://www.cellsalive.
com/cells/centriol.htm http://
www.cod.edu/people/faculty/fancher/CellStructure.htm http://www.g
eocities.com/CapeCanaveral/5229/em_txt.htm