Hello again, i have another problem...

i have 6 squash plants in my greenhouse which germinated about 10 days ago, this morning they looked nice and healthy but when i got back just now they look like this

http://i52.tinypic.com/2mxxyd.jpg

I think the reason is today the summer really came out and it reached 30 degrees outside the greenhouse (god knows how hot it was in there)...

my question: are they dead for good or will they come up again?

Thank you kind.