The palisade and spongy mesophyll are two types of tissues found inside a leaf that work together to help the plant carry out photosynthesis efficiently. They differ in their structure, location, and function.
Here’s how they differ:
1. Location:
- Palisade mesophyll is located just below the upper epidermis of the leaf.
- Spongy mesophyll lies below the palisade layer, above the lower epidermis.
2. Structure:
- Palisade mesophyll cells are elongated, tightly packed, and arranged vertically.
- Spongy mesophyll cells are irregular in shape, loosely arranged, and have large air spaces between them.
3. Function:
- The main function of the palisade mesophyll is photosynthesis. These cells contain a large number of chloroplasts to capture sunlight.
- The spongy mesophyll mainly helps in gas exchange (oxygen, carbon dioxide, and water vapor) through the air spaces and also performs some photosynthesis.
4. Amount of Chloroplasts:
- Palisade cells have more chloroplasts, making them the primary site for photosynthesis.
- Spongy cells have fewer chloroplasts, so they play a smaller role in capturing light.
5. Air Spaces:
- Palisade mesophyll has very few air spaces between cells.
- Spongy mesophyll has many large air spaces, allowing gases to circulate freely within the leaf.
In simple terms, the palisade mesophyll is the top, tightly packed layer that captures sunlight for photosynthesis, while the spongy mesophyll is the lower, loosely arranged layer that allows air and gases to move easily within the leaf.