I know this is a stupid Queastion but here goes?

I have always wondered if it's the light or the night period that pistals or buds do the most growth. I would guess night because the energy the plant stores from the light would be used to produce the bud. Whats your guys thoughts on this ?

It always seemed to me that growth was sometimes noticeable after the dark period. Now how much scientific data do I have to back that up ?
Absolutely none whatsoever. !!!

I think most growing occurs with lights on. If you give the plant 24 hours of light it still grows.

I would say that its 50/50.... various hormones are released throughout the cyclic photoperiod, and from my understanding creates a "muscle memory" like effect. Meaning that plants learn the best times to store hormones (usually during the brightest part of day and the darkest part of night) and the best times to grow (generally with bird song in the cooler morning and evening times)... The bird song thing is science not speculation:
https://www.google.com/?gws_rd=ssl#q=bird song and plant growth
SO many articles exist on the effect birds have on plant growth, IMHO its undeniable that plant growth is directly stimulated by "music" especially in the morning and evening hours.