Amount of time to photosynthesize a photon?
 

Hi.

I'm curious what amount of time passes between the reception of a photon
on the leaf surface, and then when the receptor which received the
photon is ready to receive another.

I read somewhere that it's about 10 microseconds, but I've read in other
places (including US Patent #3,930,335) that it takes around 240
milliseconds for the entire process to take place.

The irritating thing is that I swear I've read this value somewhere else
before, but I can't remember where. I also believe it's a universal
constant, and that there's a special name for it--but I may be mistaken.

Any ideas?

Thanks,
-J