Tissues213-page12

Tissues213-page12 - Water loss Diseases and pests...

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Plant Tissues - 12 Differentiation of Phloem Sieve-Tube Element and Companion Cell Dermal (Surface) Tissues 1 . Epidermis layer – Primary Growth Produced from protoderm in primary growth Generally single layer thick (There are some exceptions, such as in air roots, which are called velamen, and some leaves of tropical plants, where the additional layers serve as sun screens) Functions to protect from: Mechanical damage
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Unformatted text preview: Water loss Diseases and pests Description Outer wall thickened Often have interesting and variable shapes May be non-living at maturity Cuticle (protective waxy layer) of cutin secreted on surface on above ground parts which helps prevent water loss, and protects the plant from potential pathogens like bacteria Some waxes are produced in quantities, and are used by humans commercially...
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This note was uploaded on 01/08/2012 for the course BIO 213 taught by Professor Makina during the Fall '09 term at SUNY Stony Brook.

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