BIOL 1902 Lecture Notes - Lecture 6: Bracken, Toxicodendron Radicans, Phytoestrogens
9 Sep 2017
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Plant secondary metabolites (not used in other plant functions; for defense only) Tannins: bitter tasting substance found on barks. Milkweeds contain cardiac glycoside, caterpillars feed on them. Terpenoids: major group of plant chemical toxins, serve to repel. Poison ivy is also defended by terpenoids. Toxins that contain nitrogen are called alkaloids. Asters (flower) have leaves that are untouched. Proof that it is full of alkaloids. Insects have exoskeleton that it must shed to get bigger. Only present in early stages of growth. Rock polypody (a fern) has moulting hormones = phytoecdysones (moulting hormone made by plant) Phytoecdysones cause insects to mature too quickly and die. Insects that eat phytojuvenile hormone do not mature. Reproductive hormones made by plants affect bigger animals. When a plant is under attack an alarm is sent to prepare other parts of the plant. Travel through the plant, initiating biochemical responses. Plants pay ants for protection (similar to aphids)
