If the stomata are open, how will they affect photosynthesis and transpiration?

Question

If the stomata are open, how will they affect photosynthesis and transpiration?

Answer 1

The energy can't be transported through the plants.

Answer 2

You can think of the stomata of plants as roughly like the mouth and nose of a human. If you close your mouth and nose, your respiration (breathing) can't happen and after your stored oxygen is used up, your cells would stop working because they need oxygen to use energy and need to get rid of carbon dioxide (don't try this at home!).

In much the same way, plants transpire carbon dioxide, oxygen, and water through their stomata. When conditions cause the stomata to close (nighttime will often close them) the plant cannot transpire carbon dioxide in or waste oxygen out. Deprived of their "breathing" plant cells will stop their photosynthesis because they lack the raw materials to operate.

How does a plant continue to live without carbon dioxide? The plant cells switch over to aerobic metabolism using stored oxygen. This will carry a plant through the night, but for longer periods of closed stomata, the metabolism switches to anaerobic metabolism which has the side effect of building up poisons (alcohols) in the plant. If the plant is in anaerobisis too long it will die.