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Updated on 28th June, 2023 , 4 min read
Kranz anatomy refers to a specialized anatomical structure found in the leaves of certain plants, particularly in C4 plants. The term "kranz" is derived from the German word for "wreath" or "garland," which describes the arrangement of cells in a circular or concentric pattern.
The primary functions of kranz anatomy in plants are as follows:
Kranz anatomy enhances photosynthesis in C4 plants by spatially separating carbon fixation and the Calvin cycle, leading to more efficient carbon dioxide utilization.
Kranz anatomy reduces photorespiration by segregating carbon dioxide-rich bundle sheath cells from oxygen-rich mesophyll cells, optimizing carbon assimilation.
The arrangement of bundle sheath cells creates a carbon dioxide-rich microenvironment, facilitating efficient carbon fixation by Rubisco.
Kranz anatomy reduces water loss through transpiration by spatially separating photosynthetic cells and minimizing exposure to the atmosphere.
Kranz anatomy enables C4 plants to thrive in high light and temperature conditions by optimizing photosynthesis and minimizing the detrimental effects of photorespiration.
The Kranz anatomy is characteristic of Câ‚„ plants. In these plants, the leaves exhibit vascular bundles that are surrounded by both bundle sheath cells and mesophyll cells. The bundle sheath cells are tubular in shape and have thick cell walls. Within the bundle sheath cells, the chloroplasts are larger in size and do not possess grana, whereas the chloroplasts in the mesophyll cells are fewer and contain grana.
The following are the stages of kranz anatomy in plants:
Kranz anatomy provides a significant advantage as it enhances a plant's ability to efficiently produce its own food. It involves specialized cells surrounding the veins in leaves, optimizing light absorption and enabling increased production of sugar and oxygen for the plant's use.
The following are the characteristics of kranz anatomy in plants:
C3 plants are photosynthetic plants that fix carbon through the C3 pathway. The first product of carbon dioxide fixation in C3 plants is a three-carbon compound known as 3-phosphoglycerate (3-PGA). C3 plants include the vast majority of plant species, including most crops and many trees.
C4 plants are photosynthetic plants that fix carbon via the C4 pathway. The first product of carbon dioxide fixation in C4 plants is a four-carbon compound known as oxaloacetate or malate. This pathway enables C4 plants to capture and concentrate carbon dioxide more efficiently, reducing photorespiration and increasing their ability to thrive in high light and temperature conditions. Examples of C4 plants include maize, sugarcane, and certain grasses.
The following table summarizes the differences between C3 and C4 plants:
Particulars |
C3 Plants |
C4 Plants |
Carbon Fixation |
Use the C3 carbon fixation pathway |
Use the C4 carbon fixation pathway |
Leaf Anatomy |
Simpler leaf anatomy |
Kranz anatomy with concentric layers of bundle sheath cells surrounding the veins |
Photorespiration |
More prone to photorespiration |
Minimize photorespiration, enhancing efficiency in high light and temperature conditions |
Water Use Efficiency |
Typically lower water use efficiency |
Generally higher water use efficiency, adapted to arid or high-temperature environments |
Geographic Distribution |
Found in diverse environments |
More common in warm, tropical, and subtropical regions, where they have a competitive advantage |
Productivity |
Generally lower productivity |
Higher productivity, especially in high light, temperature, and water stress conditions |
Kranz’s anatomy is defined as two separate concentric sheets of chlorenchyma cells formed by a bundle sheath containing the majority of the chloroplasts and enclosed by a minor number of mesophyll cells.
Krantz anatomy can be found in all C4 plants. Sugarcane, maize and millets are a few examples.
C3 plants are photosynthetic plants that fix carbon through the C3 pathway. The first product of carbon dioxide fixation in C3 plants is a three-carbon compound known as 3-phosphoglycerate (3-PGA). C3 plants include the vast majority of plant species, including most crops and many trees.
C4 plants are photosynthetic plants that fix carbon via the C4 pathway. The first product of carbon dioxide fixation in C4 plants is a four-carbon compound known as oxaloacetate or malate.
C3 and C4 plants differ in photosynthesis because C3 plants complete photosynthesis only when the stomata are open, whereas C4 plants complete photosynthesis even when the stomata are closed.
The Kranz Anatomy’s main role and point of importance is that it provides the ideal site for CO2 or carbon dioxide concentration.