Solr date range problem and specific date problem

Question

I index some data include date in solr but when search for specific date, i get some record (not all record) include some record in next day for example:

http://localhost:8080/solr/select/?q=pubdate:[2010-03-25T00:00:00Z TO 2010-03-25T23:59:59Z]&start=0&rows=10&indent=on&sort=pubdate desc

i have 625000 record in 2010-03-25 but above query result return 325412 that include 14 record from 2010-03-26.

Also i try with below query, but not get right result

http://localhost:8080/solr/select/?q=pubdate:"2010-03-25T00:00:00Z"&start=0&rows=10&indent=on&sort=pubdate desc

How to get right result for specific date ???

Could you please help me?

Thanks in advanced
Hamid