Plants “eat acid” to survive dry climates, as described in Nature Australia, Spring 2002, p76. Plants take in carbon dioxide through pores in their leaves and use it to make food for the plant by photosynthesis. However, the pores that let carbon dioxide in also let water vapour out. Plants growing in dry climates could not survive if they had their pores open all day. This is a serious problem for a plant because photosynthesis needs light, which is only available during the day. In order to have a supply of carbon dioxide during the day, plants such as succulents open their pores at night when they don’t lose so much water. They also take in carbon dioxide and store it as acid until the sun comes up. Then they close their pores, keeping in precious water, and use carbon dioxide from the acid made during the night.
Editorial Comment: Such acid production is no use by itself. Neither is opening and closing the pores at the opposite time to other plants. It is only when these two features work together that the plant has an advantage in dry climates. Such multistep dependency is clearly the result of forward planning and design. (Ref. plants, design, climate)