plants drooping at night?

do plants droop at night for outdoor plant? and when the light is off for indoor plants?

My 2 start drooping about an hour before dark outside in the greenhouse. I`m not sure about indoor plants though ?

Yes its normal for the plant to rest in dark periods.There is almost no transpiration in the dark period.

I don't know what the plants do during darkness but I don't think they need any during the vegetative phase. I don't know how darkness could then help with anything during flowering then either. Maybe it's only a signal for determining when to flower. If so, maybe there could even exist other triggers that wouldn't involve the loss of energy input due to darkness. Or maybe it does just need a rest; whatever that is. And BTW this has nothing to do with the question of drooping.

at dark the plants will droop, its rest and recuperate time. they work hard when the lights are on. when my lights and co2 gen shut off my co2 in the room is at 1100ppm, when lights came on tonight it was 1023ppm. if lights were on and co2 gen was turned off it would go below 100ppm in a few hours. ive walked in when propane ran out during the light cycle and was reading 0. this alone says the plants are not processing anything at rest time.