BIOL 1902 Lecture Notes - Lecture 2: Hemicellulose, Pectin, Nectar
28 Jan 2016
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Document Summary
When you see a plant untouched, you see a war temporarily won. Plants face all the same challenges animals do, including attack from other. Seeds can be protected inside hard coats like the acorn. Other plants have a different type of defensive strategy, thistles. Thistles use animals, and cannot run away like their predators. Spines ( modified leaves). hemicellulose, and pectin make plant tissues hard to digest, called digestibility reducers. Water smartweed have inducible trichomes, only appear when out of water. Lignin gives leaves stiffness, nuts and cherry pits their hardness. Other digestibility reducers are not structural components, tannins a secondary metabolite, which are astringents - an astringent substance or liquid makes your skin drier or helps to stop a cut from bleeding. Calcium is also used as a deterrent. Arum plants have calcium oxalate crystals in their leaves. Jack-in-the-pulpit is also an arum well-endowed with calcium oxalate crystals. If you break open a milkweed, it releases latex.
