Plants have their mechanism to survive in critical environmental conditions. Although some plants are comparatively more adaptive and hence survive longer.
C4 and CAM are two such plants that are categorized as C3 plants. These plants are more adaptive to heat and hence can survive in a hotter environment where water is hardly or readily available.
Their way of minimizing water loss makes the difference between these two plants.
- C4 plants use the C4 photosynthetic pathway, which is more efficient in hot and sunny conditions.
- CAM plants follow the Crassulacean Acid Metabolism (CAM) pathway, enabling them to conserve water in arid environments.
- C4 plants separate the CO2 fixation and Calvin cycle spatially, whereas CAM plants separate them temporally.
C4 vs CAM Plants
The difference between C4 and CAM Plants is that C4 plants produce 4 carbon compounds and are mesophytic. These are summer plants like sugarcane that can sustain a hotter environment and also reduce the water supply to some extent. On the contrary, CAM plants refer to Crassulacean Acid Metabolism plants. These plants have a more effective approach to conserving water and utilize CAM Photosynthesis.
C4 plant is a type of plant that utilizes C4 carbon fixation under which the carbon dioxide (CO2) is initially bound to phosphoenolpyruvate in the mesophyll cell, which consequently results in the production or formation of four carbon compounds.
Before entering the Calvin cycle of photosynthesis, the C4 plant is first fixed into a four-carbon atom compound.
CAM refers to Crassulacean Acid Metabolism. Plants like pineapple and cacti use the CAM pathway or mechanism to reduce photorespiration.
During the night, the environment is comparatively more cooler; hence these plants collect carbon dioxide (CO2) and store the concentrated carbon dioxide as malate.
In the daytime, it is released back and consumed for photosynthesis.
|Parameters of Comparison||C4 Plants||CAM Plants|
|Definition||It is a type of plant that utilize C4 photosynthesis and produce oxaloacetate as the first stable product during the carbon dioxide fixation process||It is a type of plant that utilizes CAM photosynthesis|
|Type of Plant||C4 plants are Mesophytic||CAM plants are Xerophytic|
|First Stable Product||Oxaloacetate is the first stable product of C4 plants||In CAM plants, Oxaloacetate is formed at night while 3 PGA (phosphoglyceric acid) is formed at daytime|
|Cell Involved||Bundle sheath cells and mesophyll cells||Mesophyll cells|
What are C4 Plants?
To avoid photorespiration, some plants use the C4 photosynthesis mechanism. These types of plants are called C4 plants.
Photorespiration, on the other side, is just a wasteful reaction in which plants take oxygen and release carbon dioxide.
The C4 plants produce oxaloacetate as the first stable product during the carbon fixation process. These plants are mesophytic and utilize the C4 photosynthesis mechanism or pathway.
C4 plants include plants like sugarcane and corn.
C4 photosynthesis is the alternative pathway that reduces the opening of stomata in the daytime and also increases the efficiency of an enzyme called Rubisco, which is involved in carbon fixation.
This process takes place in bundle sheath cells and mesophyll cells. Kranz anatomy is the specialized structure in which C4 photosynthesis occurs.
During the C4 photosynthesis procedure, plants use PEP (phosphoenolpyruvate), an alternative enzyme in the mesophyll cells.
This enzyme is used in the starting or initial step of the carbon fixation procedure.
The carbon dioxide (CO2) gets fixed by PEP into C4, then to malate, and then finally transmitted or transported to sheath cells.
In the C4 photosynthesis pathway, the carbon dioxide content is fixed at two leaf regions.
What are CAM Plants?
Crassulacean Acid Metabolism (CAM) plants adapt to the dry environment and include aloe vera and cacti.
These plants use CAM photosynthesis to prevent water loss due to transpiration and evaporation. The carbon dioxide is collected at night, and the stomata open.
Later on, the absorbed carbon dioxide is later stored as malate, a four-carbon compound in vacuoles.
Oxaloacetate is the first stable product produced during CAM photosynthesis at night, and 3 PGA (phosphoglyceric acid) is produced during the daytime when Oxaloacetate or malate is transported to chloroplast and re-converted to carbon dioxide to support or facilitate photosynthesis.
Main Differences Between C4 and CAM Plants
- C4 and CAM plants varied from each other in various aspects. C4 plant is a type of plant that utilizes C4 photosynthesis and produces oxaloacetate as the first stable product during the carbon dioxide fixation process. CAM plants, on the other side, utilize CAM photosynthesis.
- C4 and CAM are different types of plants.C4 plants are mesophytic, and in the production of glucose in these plants, 12 NADPH and 18 ATP are required or needed. CAM plants are Xerophytic and require 12 NADPH and 39 ATP in the production of glucose.
- During photosynthesis, a stable product is formed or produced. C4 plants produced Oxaloacetate as the first stable product. On the contrary, CAM plants produced two stable products. Oxaloacetate is formed at night, while 3 PGA (phosphoglyceric acid) is formed during the daytime.
- During the procedure of carbon dioxide fixation, photosynthesis and other cells are involved that help in proceeding the process further. Cells involved in C4 plants are bundle sheath cells and mesophyll cells. On the other side, cells involved in the CAM plant are only Mesophyll cells.
- C4 and CAM plants undergo photosynthesis similar to other plants. But Kranz’s Anatomy makes the difference between these two. Kranz Anatomy is a specialized structure in which the photosynthesis procedure takes place. In C4 plants, the Kranz Anatomy is present. But in CAM plants, Kranz Anatomy is absent.
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Piyush Yadav has spent the past 25 years working as a physicist in the local community. He is a physicist passionate about making science more accessible to our readers. He holds a BSc in Natural Sciences and Post Graduate Diploma in Environmental Science. You can read more about him on his bio page.