Crassulacean acid metabolism - How Cacti survive

I'm a long time fan and grower of succulents. And fascinated with the adaptation of their basics for surviving and thriving.

Plants all do the essentials - take up nutrients, fluids, photosynthesize and exchange CO2 for Oxygen as a waste product in the process.

Most of it all happens simultaneously. Plants take up water, their stomata open and they breathe, photosynthesize in daytime. Succulents do so as well, but make the exchange differently than other plants, though.

Given their harsh environments, succulents developed a two step process. They take up water as available and photosynthesize in daylight. Yet to conserve water they developed a holding tank process to make the gas exchange. Stomata are closed during the day. Respiration in a harsh climate is a key to maximizing water use. O2 waste gas, a result of the day's photosynthesis, is transferred to a mediary molecular bond. When night falls, the succulents' stomata open, the bond breaks and they complete the process. Succulents breathe at night.