Kranz anatomy is found in _____ plant.
C4
Kranz Anatomy in Plants
Kranz anatomy is a special anatomical structure found in the leaves of certain plants, specifically those that utilize the \(\text{C}_4\) photosynthetic pathway. This unique arrangement is a key adaptation that helps these plants thrive in hot, dry environments.
Features of Kranz Anatomy
The term 'Kranz' is German for 'wreath', which describes the characteristic arrangement of cells in the leaves of \(\text{C}_4\) plants exhibiting this anatomy. Key features include:
- Bundle Sheath Cells: These are large cells that form a ring or sheath around the vascular bundles (xylem and phloem) in the leaf. They are typically thick-walled and contain a large number of chloroplasts.
- Mesophyll Cells: These cells are located between the bundle sheath and the leaf surface. In Kranz anatomy, they are often arranged in a concentric layer around the bundle sheath cells. They also contain chloroplasts.
- Reduced Intercellular Spaces: Compared to \(\text{C}_3\) leaves, leaves with Kranz anatomy often have fewer and smaller intercellular air spaces in the mesophyll layer.
Function of Kranz Anatomy in \(\text{C}_4\) Photosynthesis
Kranz anatomy facilitates the spatial separation of the two main steps of \(\text{C}_4\) photosynthesis:
- Initial carbon fixation occurs in the mesophyll cells, where \(\text{CO}_2\) is fixed by the enzyme PEP carboxylase into a four-carbon compound.
- This four-carbon compound is then transported to the bundle sheath cells.
- In the bundle sheath cells, the four-carbon compound is decarboxylated (broken down) to release \(\text{CO}_2\). This released \(\text{CO}_2\) is then concentrated around Rubisco, the enzyme responsible for the Calvin cycle, which takes place within the bundle sheath chloroplasts.
This spatial separation and the concentration of \(\text{CO}_2\) in the bundle sheath cells significantly reduces photorespiration, a process that wastes energy in \(\text{C}_3\) plants, especially under hot, dry conditions when stomata close to conserve water, leading to low internal \(\text{CO}_2\) and high \(\text{O}_2\) levels.
Comparison with \(\text{C}_3\) Plants
\(\text{C}_3\) plants, which do not have Kranz anatomy, perform both initial carbon fixation and the Calvin cycle within the mesophyll cells. They lack the specialized, enlarged bundle sheath cells rich in chloroplasts that are characteristic of Kranz anatomy.
Therefore, Kranz anatomy is a defining feature of \(\text{C}_4\) plants.
Important Questions from Photosynthesis
Which plant pigment is present in tomatoes?
Which one of the following reactions takes place during the reduction phase of the Calvin - Benson cycle?
The following statements were made with the assumption that the concentration of 3- phosphoglycerate is high inside chloroplasts of an actively photosynthesizing leaf.
A. There will be high concentration of triose phosphate in the chloroplast.
B. The activity of ADP-glucose pyrophosphorylase will be inhibited.
C. The carbon flow will be diverted from sucrose to starch.
D. Starch synthesis will be inhibited and carbon flow will be more towards sucrose synthesis.
Which one of the following combinations of above statements is correct?
The table below shows photosynthetic type, temperature and sunlight intensity levels.
Photosynthetic Type Temperature Sunlight Intensity A. C3 Plant i High P. High B. C4 plant ii Moderate Q. Moderate iii Low R Low Which of the following correctly matches the plant photosynthetic type with the temperature and sunlight conditions in which photosynthetic rate per unit leaf area is maximum for that plant?
Which one of the following are the correct encoding sites of large and small subunits of Rubisco enzyme in red and brown algae?
