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The upcoming discussion will update you about the difference between dorsiventral leaf, Isobilateral leaf and centric leaf.
Difference # Dorsiventral Leaf:
1. Internally the leaf is differentiated into upper and lower epidermis and mesophyll, which lies in between the two epidermises.
2. The distribution of stomata is usually restricted to lower epidermis.
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3. Mesophyll is composed, of palisade and spongy parenchyma. The palisade cells are elongated and situated in transverse plane towards the upper epidermis. The spongy parenchyma cells are more or less isodiametric in shape and occur in between the palisade and lower epidermis with profuse intercellular spaces.
4. The vascular bundles, in the transverse section of leaf, are of different sizes and not arranged in a transverse line. Ex. dicotyledonous leaf.
5. The vascular bundles are usually surrounded by bundle sheath consisting of a single layer of parenchyma.
Difference # Isobilateral Leaf:
1. Internally the leaf is differentiated into upper and lower epidermis, and mesophyll, which occurs in between the two epidermises.
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2. The stomata are distributed on both the epidermises.
3. The mesophyll cells are composed of one type of cells, i.e. the cells are either more or less isodiametric (simulate spongy parenchyma) or elongated (simulate palisade parenchyma); the cells lie in between the upper and lower epidermis with little inter-cellular spaces.
4. In the transverse section of leaf the vascular bundles are more or less of same sizes and arranged in a transverse line. Ex. monocotyledonous leaf.
5. The vascular bundles are usually surrounded by bundle sheath, which may be one or two layered. In the latter case the outer sheath is composed of thin walled parenchyma cells. The cells of the inner sheath are smaller in cross-sectional diametre and thick walled in comparison to the outer sheath. The inner sheath is termed as mestome sheath and its cells are thickened with suberin.
Difference # Centric Leaf:
1. Internally the leaf is differentiated into epidermis and mesophyll; a single epidermis is present all round the periphery and it encloses the mesopyll.
2. The stomata are distributed all round the circumference of epidermis.
3. The mesophyll may be composed of one type of cells or may be differentiated into palisade and spongy parenchyma. In the latter case the palisade cells occur all round the periphery of the cylindrical leaf (ex. Hakea).
4. In the transverse section of leaf the vascular bundles are present either in a line or in a ring. Ex. onion, Hakea etc.
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5. The vascular bundles are usually surrounded by bundle sheath, which is single layered. Sometimes sclerenchymatous fibres occur on both sides of vascular bundles.
