What's the stressing temp for canabis?

I have 32C and 45% humidity in my grow space. Now i'm not sure, would these conditions stress a plant?

Your plant is right at about the stressing point.

If you maintained that temperate you would need extremely good aeration of the room. The humidity isn't what I'd worry about if it's at 45%.
You're going to need to find a way to get the temperate down a minimum of 5 degrees. The optimum temp for marijuana is 75-85 Fahrenheit give or take.
By keeping the plant at temperatures it's at now you are exposing it to more "variables". Higher possibilities of mold, heat stress, and other deficiencies could occur.

Plants can definitely live in temps of 90 degrees (example : plants outdoors in jamaica), but in a self enclosed grow room you could potentially effect your yield as well.

You are right at the top end of the temperature limit. Generally you want it to be tween 23 and 29c or 75 - 85 F. Your humidity is okay, unless you are vegging, then a little higher, around 55-60%, is better.

Just make sure they got fresh air coming in and air is being evacuated first, then concern yourself with rh/temps.

How can i increase humidity?
I've been putting a frozen bottle where the air comes in, got the tip from someone here.