CAM Plants Definition
CAM plants, short for Crassulacean Acid Metabolism plants, are a type of plant that has evolved to survive in arid conditions.
They utilize a carbon fixation pathway that allows them to take in CO2 during the night through their stomata and store it as an organic acid until the next day when photosynthesis can occur.
This adaptation helps them conserve water by reducing the amount of time their stomata need to be open during the day. Examples of CAM plants include cacti and pineapples.
Steps of CAM Photosynthesis
Crassulacean acid metabolism (CAM) is a specialized pathway that evolved in some plants as an adaptation to arid conditions. CAM photosynthesis stores photosynthetic products at night, allowing stomata to remain closed during the day. The following are the steps of CAM photosynthesis:
1. At night, stomata open and CO2 enters the plant.
2. CO2 is converted into organic acids and stored in vacuoles.
3. During the day, stomata close to conserve water.
4. Organic acids are broken down into CO2, which enters the Calvin cycle for sugar production.
CAM plants minimize photorespiration and save water by separating these steps in time between night and day. CAM plants are typically dominant in very hot, dry areas like deserts.
Examples of CAM Plants
CAM (Crassulacean Acid Metabolism) plants are a group of plants that have adapted to dry environments by opening their stomata at night to take in CO2 and storing it as malic acid. During the day, the stored CO2 is released for use in photosynthesis.
Examples of CAM plants include pineapple, agave, opuntia, aloe vera, vanilla, cactus, jade plant, orchids, sedum, kalanchoe, and snake plant.
Pineapple is a classic example of a CAM plant. During the day, pineapple plants close their stomata to stop losing water due to evaporation. Then at night when temperatures are cooler and humidity is higher they open their stomata to allow carbon dioxide to enter the leaves for photosynthesis.
Cacti are also common examples of CAM plants. They have thick reduced leaves with a low surface-area-to-volume ratio and sunken stomata that help them conserve water in arid environments.
CAM plants can be found in both arid and semi-arid regions as well as epiphytic habitats such as rainforests. They often show xerophytic features such as thick cuticles and reduced leaves with low surface area-to-volume ratios that help them conserve water.
Cacti
Cacti are a type of succulent plant that has adapted to survive in arid climates. They have a sponge-like interior that stores water, and a thick, waxy epidermis covering the outside of the plant to prevent water loss.
Cacti do not have normal leaves like trees; instead, their spines are modified leaves that protect them from animals and break up evaporative winds blowing across pad surfaces.
Cacti photosynthesize in the epidermis using CAM (crassulacean acid metabolism) photosynthesis, which is unique to succulents. In CAM photosynthesis, carbon dioxide is collected through holes in the cactus’ leaves called “stomata” and converted into sugar and oxygen.
Acid is stored at night within the plant so that during the day it can be turned into sugar without losing water through open stomata.
Other examples of CAM plants include pineapple, agave, orchids, and bromeliads. CAM plants are typically dominant in very hot, dry areas like deserts because they minimize photorespiration and reduce water loss from leaves when temperatures are higher and cooler respectively.
Cacti have broad and shallow root systems that soak up rainwater quickly. Small rain roots grow as soon as the soil is moistened by rain but later dry up. When it rains in the desert, cacti quickly take in large amounts of water through their roots.
The inside of a cactus can hold a lot of water – some saguaro cacti can hold up to 2,000 pounds (907 kilograms) of water – which allows them to survive for months without rain because they need very small amounts of water to function.
Agave
Agave is a genus of succulent plants that are native to arid and semi-arid regions of the Americas. There are over 200 species in the Agave genus, all of which are obligate CAM (Crassulacean Acid Metabolism) plants.
Agave has been used for various purposes such as beverages, food, fiber, medicines, shelter, and ornamentals. Some species of Agave have the potential as advanced biofuel crops in water-limited regions due to their greater cold tolerance and high water use efficiency.
Agave is also used for making fermented beverages such as tequila and mezcal. Regulations were enacted to enhance the marketability of tequila as a regionally defined product.
In addition to fermented beverages, agave syrup or agave nectar has emerged as a sweetener within the past 25 years. The sweetener has been marketed as a bottled product to use as a substitute for sugar or honey in cooking and baking.
Agave can be grown for fiber production. Commercial agriculture for Agave fiber crops typically uses species such as Agave fourcroydes and Agave sisalana. However, these commercial species do not have the cold tolerance of A. americana which has the potential for biomass production on land that was previously used for Agave fiber crops.
Overall, Agave is a versatile plant with various uses ranging from biofuel crops to sweeteners. Its ability to grow in arid and semi-arid regions makes it an attractive crop option in water-limited areas.
Clusia Pratensis
Clusia pratensis is a shrub or tree that grows primarily in the wet tropical biome. It is native to Costa Rica to Colombia. Clusia pratensis exhibits facultative CAM, which means it can switch between C3 and CAM photosynthesis depending on environmental conditions. The plant has thick and leathery leaves shaped like fat teardrops or paddles.
It is important to note that there are two species of Clusia commonly sold as “Pitch Apple” in stores: Clusia guttifera and Clusia rosea. Some stores label both species as “Pitch Apple,” which can cause confusion for buyers.
If you are buying a plant labeled Pitch Apple, look for the botanical name to be sure it’s the Clusia you want. C. rosea is rarely sold in stores so it’s likely the one you see marked Pitch Apple is actually guttifera.