CAM Full Form

CAM stands for Crassulacean acid metabolism. This is a type of plant respiration that stores water in plants’ leaves at night. When it gets hot, it builds up CO2 as a byproduct, causing plants to open their stomata to keep the reaction going. The same process is used when plants dry out and need to take up water rapidly. Crassulacean acid metabolism is thought to be the most efficient form of photosynthesis. It has a CO2-releasing reaction when excess CO2 is produced. It is also the only form of photosynthesis that some bacteria can use. 

Description and significance of CAM:

 To avoid photorespiration, C3 plants are one of the few types of plants that use crassulacean acid metabolism to make more efficient use of carbon dioxide in photosynthesis. These plants will continue to grow through the night, and store sugars for later use in parts shaded from sunlight.

When photosynthesis is in full operation, the process of photosynthesis expels carbon dioxide into the atmosphere as a waste product. In Crassulacean acid metabolism (CAM), plants store carbon dioxide during the night, when it is dark, and release it during the day as a waste product. This process reverses the original flow of carbon dioxide, which is expelled into the atmosphere and used in photosynthesis by plants. We can compare this process to storing CO2 by organisms found in aquatic environments, which then use the CO2 for photosynthesis when exposed to sunlight.

Carbon Dioxide Storage (CAM):

The buildup of carbon dioxide is called ‘internal storage’. The release of the stored carbon dioxide is called ‘exchange’. In CAM, the plants store carbon dioxide in various places like flower buds and seeds; however, it is usually in the form of starch. There are two different types of carbon fixation used by CAM plants; the Calvin cycle and the C3 cycle. The Calvin cycle is used by grasses and sedges, while most other plant families use the C3 cycle. In CAM, the carbon dioxide is stored in their starchy food during the night when they are not photosynthetically active. In the morning, the stems and leaves are used to release the stored carbon dioxide, which the plants use in photosynthesis.

Processing at night time: During their nighttime storage of carbon dioxide, a CAM plant will turn over half of its starch reserves into carbohydrates. If these plants store a large amount during their nighttime period (more than 12 hours), this will cause a malignant growth called ‘cauliflower disease’. This disease causes irregularity in growth and a strong discolouration of these plants. Usually, you will see this disease in the spring.

Storage system:

The CAM plants also have a special layer of cells in their leaves called guard cells. These cells have a special mechanism that allows them to open or close themselves depending on the amount of carbon dioxide stored in these leaves at night. For CAM plants to be able to store and use carbon dioxide during their nighttime hours, they must have certain characteristics. The major one is that they have to have a special mechanism to regulate the amount of carbon dioxide, water and food intake while they are sleeping at night. They have specialised internal membranes that allow carbon dioxide and water to exchange with their leaves. These membranes are called xylem, phloem and endodermis. The xylem carries water while the phloem carries food (starch), and the endodermis allows transpiration. 

The mechanism of CAM is based on the activation of the enzyme phosphoenolpyruvate carboxylase (PEPC). This enzyme is necessary for photosynthesis, but it is inactive at night. As a result, no carbon dioxide is stored for use in photosynthesis during hours when light does not exist. PEPC does not become active until several hours after sunrise.

Plants use two different chemicals to avoid this problem by turning on the PEPC. When exposed to the sun’s light, plant pigments called cryptochromes are activated. Cryptochromes are not found in all plants, but they are necessary for CAM to work in those that do. Cryptochromes work by turning on other proteins, which turn on more proteins until finally PEPC is activated and begins storing CO2. The second chemical that turns on PEPC is ABA (abscisic acid). ABA is found in all plants and is a hormone in plants that allows them to control many of their reactions to the environment.

Conclusion: 

CAM is interesting because it can be used in everyday life. For example, when one of your ice cubes is melting, you may not notice that the water is less acidic because it is so cold. But on a hot summer day, ice cubes will most likely melt faster because the water around them is more acidic. So, the use of CAM in nature can affect life in everyday life, which many people may not notice. CAM plants are a major draw for many tourists and divers who wish to learn about these types of plants.