The vertical section of a dorsiventral leaf through the lamina shows three main parts, namely epidermis, mesophyll and vascular system.
Epidermis: The epidermis which covers both the upper surface(adaxial epidermis) and the lower surface(abaxial epidermis). of the leaf has a conspicuous cuticle. The abaxial epidermis generally bears more stomata than the adaxial epidermis. The latter may even lack stomata.
Mesophyll: The tissue between the upper and the lower epidermis is called the mesophyll. Mesophyll which possesses chloroplast and carry out photosynthesis is made up of parenchyma. It has two types of cells the palisade parenchyma and the spongy parenchyma. The adaxially placed palisade parenchyma is made up of elongated cells, which arranged vertically and parallel to each other. The oval or round and loosely arranged spongy parenchyma is situated below the palisade cells and extends to the lower epidermis. There are numerous large spaces and air cavities between these cells.
Vascular system: This includes vascular bundles, which can be seen in the veins and the midrib. The size of the vascular bundles is dependent on the size of the veins. The veins vary in thickness in the reticulate venation of the dicot leaves. The vascular bundles are surrounded by a layer of thick walled bundle sheath cells.
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| Anatomy of dicot leaf |
