[Arabidopsis] total number of genes changed from specific stress for hypergeometric test

[galonyae from post.tau.ac.il]

Hi
I want to calculate the p-value of the enriched list of genes  
(according various
classifications, such as : cold, heat, uvb ext) from my microarray  
experiment, using
hypergeometric test.
For this calculation I need the total number of genes belonging to a  
specific group (e.g.
cold) in a chip.
Does anyone know where can I found how many genes are changed in each  
biotic or abiotic
stress. for example: how many genes are changing in a chip as a result  
of cold stress (up
and down regulated)?

Thanks in advance, Yael