LEAVES ARE THE MAIN SITES OF PHOTOSYNTHESIS and transpiration (water loss by evaporation ) in plants A typical leaf consist of a thin , flat lamina (blade) supported by a network of veins , a petiole(leaf stalk); and a leaf base ,where the petiole join the stem .
Leaves can be classified as simple , in which the lamina is a single unit , or compound , in leaflets.Compound leaves may be pinnate , with pinnae (leaflets) on both sides of a rachis (main axis ),or palmate, with leaflets arising from a single point at the tip of the petioleLeaves can be classified further by the overall shape of the lamina , and by the shape of the lamina's apex ,margin and base.
PHOTOSYNTHESIS
PHOTOSYNTHESIS IS THE PROCESS by which a plant make their food using sunlight,water, and carbon dioxide .It takes place inside special structures in leaf cells called chloroplasts.The chloroplasts contain chlorophyll , a green pigment that absorbs energy from sun light .During photosynthesis , the absorbed energy is used to join together carbon dioxide and water to form the sugar glucose , which is the energy source for the whole plant ;oxygen , a waste product , is released in the air .Leaves are the main sites of photosynthesis , and have various adaptation for that purpose :flat laminae,( blades)provide a large surface for absorbing sun light ;stomata ( pores ) in the lower surface of the laminae allow gases (carbon dioxide and oxygen ) to pass into and out of the leaves ;and an extensive network of veins bring water into the leaves and transport the glucose produced by photosynthesis to the rest of the plant.
Leaves can be classified as simple , in which the lamina is a single unit , or compound , in leaflets.Compound leaves may be pinnate , with pinnae (leaflets) on both sides of a rachis (main axis ),or palmate, with leaflets arising from a single point at the tip of the petioleLeaves can be classified further by the overall shape of the lamina , and by the shape of the lamina's apex ,margin and base.
PHOTOSYNTHESIS
PHOTOSYNTHESIS IS THE PROCESS by which a plant make their food using sunlight,water, and carbon dioxide .It takes place inside special structures in leaf cells called chloroplasts.The chloroplasts contain chlorophyll , a green pigment that absorbs energy from sun light .During photosynthesis , the absorbed energy is used to join together carbon dioxide and water to form the sugar glucose , which is the energy source for the whole plant ;oxygen , a waste product , is released in the air .Leaves are the main sites of photosynthesis , and have various adaptation for that purpose :flat laminae,( blades)provide a large surface for absorbing sun light ;stomata ( pores ) in the lower surface of the laminae allow gases (carbon dioxide and oxygen ) to pass into and out of the leaves ;and an extensive network of veins bring water into the leaves and transport the glucose produced by photosynthesis to the rest of the plant.
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