Respiration Phase Question

[Rider509]

Maybe someone with a better idea of plant processes can explain what I’m seeing.
This chart is a 24 hour representation of the growing environment with mature three to four foot tall plants in a sealed room. At lights out the fans, humidifier, and CO2 are also turned off. During lights out the environment is static. No outside heating or cooling or air movement.
We can see a steady drop in temperature and humidity for the first four hours, and then a slow rise in temperature occurs. Is this the action of exothermic respiration? Are the plants actually warming up at this point?

 

[Kismet]

I think they do heat up after storing all that light all day and expire some water in the evenings lights out. RH is always higher then. So yes they expell water to stay warmish and not get root rot or mold if they can.

 

[Rider509]

I’m not sure that’s true, Kismet. In my sealed environment I routinely see the humidity drop after lights out due to the plants not transpiring. It’s an accepted fact that plants transpire only during the day while respiration can occur all day, but primarily after lights out.
I haven’t followed up with any research but I have to believe that the plants warm up as they convert the stored energy from sugars to carbohydrates. I was kinda hoping someone would spoon feed me the answer, lol, but it looks like I’m going to have to crack the books on this one.