Answer:
According to the given search results, cacti are able to survive in low rainfall regions such as the Sonoran Desert because they have adapted a range of features that allow them to conserve and use water more efficiently. For example, cacti have developed thick, fleshy stems and leaves that can store water, reducing the need for regular rainfall. Some cacti even have specialized root systems that can quickly absorb water from the soil when there is a sudden rainfall or moisture availability. Additionally, cacti often have spines instead of broad leaves to help reduce water loss through transpiration. Spines also deter animals from eating the plant, which is an important survival advantage in a harsh environment.
Another adaptation of cacti is their ability to conduct photosynthesis at night, which reduces water loss through transpiration during the day and allows them to conserve water. This is known as crassulacean acid metabolism (CAM) photosynthesis and is widespread in desert plants, including most cacti. By opening their stomata at night to absorb carbon dioxide and storing the carbon dioxide until daylight, the plant can keep stomata closed and limit water loss during the hot, dry daytime hours.
Overall, the water-conserving adaptations of cacti are key to their survival in low rainfall regions such as the Sonoran Desert. Their fleshy stems and leaves, specialized root systems, spines, and CAM photosynthesis are effective strategies for maximizing water use efficiency and reducing water loss in a harsh and unpredictable environment.
Step-by-step explanation: