Photosynthesis is the process through which plants convert energy from the sun into sugar. It occurs through two stages: light-dependent reactions (daytime) and dark reactions or the Calvin Cycle (nighttime). During the daytime, the sun’s energy is taken in by the chlorophyll and is transferred to the hydrogen ions. Water is then separated and oxygen is produced. During the night, carbon dioxide from the air is taken in and made into sugar. The energy from the light-dependent reactions is used to fuel this. The result is sugar molecules with energy stored in their carbon-carbon bonds. Depending on their environment, plants adapt this process.
In the desert, because of the high temperatures, strong, direct sunlight and dryness, plants use a method called CAM. The carbon dioxide is taken in at night. The stomata, which allow water to pass through the plant’s leaves, are only open at night, so that they conserve water during the hottest hours. During the day, the sunlight fuels the stored sugars from the night’s process to continue the process of photosynthesis. However, the carbon dioxide stored from the night can run out, therefore stopping the photosynthesis. That is why plants in the desert, though they can live with the dry, hot conditions, grow very slowly and are tough so as to withstand destruction.