Leaf Anatomy - General Features of the Lamina (Blade) |
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| The Three Tissue Systems are
Omnipresent! Epidermal - Ground (Mesophyll) - Vascular (Veins) |
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| Textbook Leaves | |
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Leaf Anatomy - General Features of the Lamina (Blade) |
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| The Three Tissue Systems are
Omnipresent! Epidermal - Ground (Mesophyll) - Vascular (Veins) |
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| Textbook Leaves | |
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Leaf Anatomy - Lamina or Blade |
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| The Adaxial Epidermis generally has a thick
cuticle on the upper (adaxial) surface. Secretory &
Non-secretory Trichomes may be present. Stomata may occur on the adaxial epidermis but these are most frequent on the lower (abaxial) surface.
The Abaxial Epidermis usually has a thin cuticle. However, it may have a dense layer of trichomes which increase the "boundary layer" effect. This decreases the rate of transpiration. Stomata are routinely present on the abaxial surface and are usually more abundant than on the abaxial surface when both surfaces have stomata. |
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Lamina from ohia' lehua Metrosideros polymorpha showing a thick adaxial cuticle (C) and abaxial Trichomes (T) |
Same but with Polarizing Optics. This brings out trichomes, crystals and cells with thick, highly organized Cell Walls |
Mesophyll |
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| Palisade mesophyll is composed of columnar cells that can be one to several layers thick. It is most common on the adaxial side of the leaf where sunlight is usually most abundant. Palisade parenchyma are more efficient for photosynthesis and water retention because of their large surface areas but small intercellular air spaces. |
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Spongy mesophyll  is usually found on the abaxial side of the leaf. It may consist of stellate
parenchyma or chains of elongate cells which have large,
lateral intercellular spaces. This allows rapid diffusion of
gases like CO2. |
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| Some plants have a uniform mesophyll which is composed of relatively isodiametric
cells.
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 Mesophyll Cells in the Wheat Lamina do not have pronounced shapes, and give a uniform appearance. |
Nerium oleander has pronounced Palisade and Spongy Layers |
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