I am having a similar problem and also have pictures. Here is my thread, if anybody can help out I would appreciate it.

http://boards.cannabis.com/showthread.php?t=70834
GrowerXLT Reviewed by GrowerXLT on . Flowering, but leaves are yellow and dying - Please help Hey, so here's my deal.... I have two plants. Both started as feminized seeds. One is White Widow, the other Easy Bud. I vegged for about 7 weeks and now I have been flowering for about 4 and a half weeks. Most of the lower leaves on both plants have died or fallen off. There are a lot of bud sites, but even some of the leaves by the flowers are yellowing, curling and dying. Using 400 W HPS with relighting bulb (supposed to be similar to hortilux). Used 400 W MH for veg. Rating: 5