by admin on Sunday, March 14, 2010 18:18 under Interesting Facts.
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- Leaves are a plant’s powerhouse, using sunlight to join water and carbon dioxide to make sugar, the plant’s fuel.
- Leaves are broad and flat to catch maximum sunlight.
- Leaves are joined to the stem by a stalk called a petiole.
- The flat part of the leaf is called the blade.
- The leaf blade is like a sandwich with two layers of cells holding a thick filling of green cells.
- If you hold a leaf blade up to the light, you can clearly see the pattern of its veins.
- The green comes from the chemical chlorophyll. It is this that catches sunlight to make sugar in photosynthesis.
- Chlorophyll is held in tiny bags in each cell called chloroplasts.
- A network of branching veins (tubes) supplies the leaf with water. It also transports the sugar made there to the rest of the plant.
- Air containing carbon dioxide is drawn into the leaf through pores on the underside called stomata. Stomata also let out water in a process called transpiration.
- To cut down water loss in dry places, leaves may be rolled-up, long and needle-like, or covered in hairs or wax. Climbing plants, such as peas, have leaf tips that coil into stalks called tendrils to help the plant cling.
