Plant tissues

• The leaf is a plant organ like any organ the leaf contains different tissues
• The top and bottom of the leaf are covered with a layer of very thin cells called the epidermal cells and from epidermal tissue
• The epidermis protects the surface of the leaf
• The upper epidermis is transparent Allowing light to pass through to the photosynthetic cells bellow
• The upper epidermis is also covered with a thin layer of oily material called the waxy cuticle it reduces the evaporation of water from the surface of the leaf preventing the leaf from drying out
• The lower epidermis has tiny pores called stomata
• Stomata allow carbon dioxide to enter the leaf and oxygen to leave
• Stomata help to control the amount of water vapour that can pass out the leaf
• On either side of the stomata we find guard cells
• At the top of the leaf we find The palisade mesophyll which consists of pallasade cells
• Palisade cells are packed pull of chloroplasts
• Under the palisade mesophll we find the spongy mesophyll
• The spongy mesophyll is full of air spaces allowing carbon dioxide to diffuse from the stomata through the spongy mesophyll to the Palisade cells
• Xylem tissue transports water from the roots to the stem and leaves
• The movement of sugars and other molecules through phloem tissue is called translocation
• We find meristem tissue at growing tips eg shoots and roots
• Meristem tissue contain stem cells these can diffentiate into different types of tissue