Why do the leaves of gulmorhar changes in evening and in morning?

Question

Why do the leaves of gulmorhar changes in evening and in morning?

Answer 1

The leaves of gulmohar, Delonix regia are doubly pinnate and have a feathery appearance. In the morning when, the sun becomes warmer, the leaflets answer to the drying effect by moving upwards. In the evening the temperature descends and the leaflets too.

This phenomenon is called xerofotic movement and is sometimes to find in Caesalpinieae ( family )

More about mechanism:

http://www.jstor.org/pss/2469537

Sorry, but it`s an abstract only, no pics!