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Plant Cells and Tissues
Tissue Types in Plants
- Epidermal Tissue
- Palisade Mesophyll
- Spongy Mesophyll
- Xylem and Phloem
- Meristem Tissue: Located at GROWTH POINTS at the TIPS of shoots and roots. These cells specialise through DIFFERENTIATION to become various specialised plant cell types.
The Leaf
Composed of several tissue types, including epidermal, mesophyll, xylem and phloem tissues, the leaf is a plant organ and is key for PHOTOSYNTHESIS and GAS EXCHANGE.

- UPPER EPIDERMIS
- This is the outermost layer of cells on the leaf. It is TRANSPARENT so it allows sunlight to pass through to the chloroplast-rich layers beneath, which is vital for photosynthesis.
- PALISADE MESOPHYLL
- Located just below the upper epidermis, this layer consists of CLOSELY PACKED CELLS that contain MANY CHLOROPLASTS to maximise light absorption for photosynthesis.
- SPONGY MESOPHYLL
- The cells here are arranged MORE LOOSELY, which creates air spaces to facilitate the efficient diffusion of gases like carbon dioxide (CO₂). This structure enhances the leaf's SURFACE AREA TO VOLUME RATIO.
- LOWER EPIDERMIS
- Similar to the upper layer but mainly contains STOMATA and GUARD CELLS that regulate gas exchange and water loss from the leaf.
- STOMATA
- These are HOLES primarily found on the lower epidermis that allow for the exchange of oxygen and carbon dioxide. They open during the day to facilitate photosynthesis and close at night to conserve water.
- GUARD CELLS
- These are cells found either side of the stomata and can change shape to open or close them. They REGULATE WATER AND GAS EXCHANGE by reacting to environmental conditions.
- XYLEM AND PHLOEM
- This is the plant's TRANSPORT SYSTEM. The xylem transports water and minerals from the roots upward throughout the plant, while the phloem distributes sugars and other nutrients from the leaves to the rest of the plant.
Plant Cells and Tissues
Tissue Types in Plants
- Epidermal Tissue
- Palisade Mesophyll
- Spongy Mesophyll
- Xylem and Phloem
- Meristem Tissue: Located at GROWTH POINTS at the TIPS of shoots and roots. These cells specialise through DIFFERENTIATION to become various specialised plant cell types.
The Leaf
Composed of several tissue types, including epidermal, mesophyll, xylem and phloem tissues, the leaf is a plant organ and is key for PHOTOSYNTHESIS and GAS EXCHANGE.

- UPPER EPIDERMIS
- This is the outermost layer of cells on the leaf. It is TRANSPARENT so it allows sunlight to pass through to the chloroplast-rich layers beneath, which is vital for photosynthesis.
- PALISADE MESOPHYLL
- Located just below the upper epidermis, this layer consists of CLOSELY PACKED CELLS that contain MANY CHLOROPLASTS to maximise light absorption for photosynthesis.
- SPONGY MESOPHYLL
- The cells here are arranged MORE LOOSELY, which creates air spaces to facilitate the efficient diffusion of gases like carbon dioxide (CO₂). This structure enhances the leaf's SURFACE AREA TO VOLUME RATIO.
- LOWER EPIDERMIS
- Similar to the upper layer but mainly contains STOMATA and GUARD CELLS that regulate gas exchange and water loss from the leaf.
- STOMATA
- These are HOLES primarily found on the lower epidermis that allow for the exchange of oxygen and carbon dioxide. They open during the day to facilitate photosynthesis and close at night to conserve water.
- GUARD CELLS
- These are cells found either side of the stomata and can change shape to open or close them. They REGULATE WATER AND GAS EXCHANGE by reacting to environmental conditions.
- XYLEM AND PHLOEM
- This is the plant's TRANSPORT SYSTEM. The xylem transports water and minerals from the roots upward throughout the plant, while the phloem distributes sugars and other nutrients from the leaves to the rest of the plant.