BSC 2011 Lecture Notes - Lecture 10: Canavanine, Abscission, Chemical Warfare
21 Sep 2016
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Plants have constitutive and induced responses to pathogens and herbivores: constitutive defenses. Cuticle: epicuticular waxes- deposited atop the cuticle. Resulting in physical damage to insects feeding on the plant. Dense hairs may also obscure the epidermis. Also contains secondary metabolites that may be poisonous. Secondary metabolites- substances not essential to plants. Chemical warfare to repel or inhibit herbivores. Canavanine- non-protein amino acid produced by some legumes. Plants have mechanical and chemical defenses against pathogens and herbivores. Plants develop in response to the environment: cues that influence growth are regulated by hormones and photoreceptors. Hormones- chemical signals that act at very low concentrations at sites often far from where they are produced. Once seedling emerges from soil, ethylene production stops, allowing cells of inner surface to elongate. Apical buds inhibit growth of axillary buds. Diffusion gradient results in more axillary bud growth an branching lower down the stem. Terminal bud produces auxin, prevents lateral buds from growing: root initiation.
