Complete Dudley Notes (including lectures)

Complete Dudley Notes (including lectures) - BIO 1AA3...

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BIO 1AA3 – Dudley’s Material Plant Volatiles Plant Volatiles - Organic compounds with a low boiling point from 50° to 250° or a high vapour pressure - Consequently at room temperature, volatiles are present in a gaseous state. - Ex. Volatiles could be explosive and toxic Volatiles Ecological Functions - Pollinator attraction - Antimicrobial activity - Protection against heat stress - Plant hormones - Responses against herbivores Role of Volatiles in Herbivore Defenses - Induced defenses are usually toxins and anti-digestives, but also include physical defenses preuertiy - Induced means these defenses are only present when the herbivores are - They are absent when herbivores are absent are induced by the actions of Why have inducible defenses? - They leave the plant unprotected until after it is attacked - If having defended is costly, then inducible defenses make sense - They could spend their COH, N+ into growth and reproduction How do herbivores induce defenses in a plant? - They damage the plant (obviously) - The less obvious thing that they do is they have saliva that induces plant Example: - Caterpillars model live on a plant - Caterpillars create holes in leaves which can be created by hole-punching - Damaged plants release volatile hormones, including ethylene and jasmonates or jamonic acid (involved in plant communication) - The caterpillar moves along the plant and licks saliva - Both mechanisms signal transduction pathway (i.e. molecular mechanism) - The plant senses the environment and produces a change in the gene - The plant synthesizes and releases ethylene and jasmonates - Parasitic warps are tiny they lay their eggs inside the caterpillar and the egg will hatch out and the larvae will eat out the caterpillar from inside-out - It is highly necessary - they are major bio-control agents - Parasitoid wasps are attracted to the volatiles from wounded plants - Attracting parasitic wasps and the hormones can affect other parts of the - They have a different mechanism for moving things around - The volatiles also induce defenses in other parts of the plant Do other plants eavesdrop on this signal? - Plants ‘eavesdrop’ for their own protection More Detailed Information
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Insect-da m ag ed sag ebrush has a novel way of broadcasting to n e arby plants that a predator is in the are a: It releas es a bouquet of airborne odors and perfum es. If wild tobacco is growing n e arby, it will "eavesdrop" on thes e che mical signals, and in In both gre enhouse and field experiments, the rese archers spread sag ebrush clippings with their perfum es and odors around wild tobacco plants. Each experiment included *an isolated tobacco plant as a control, *a tobacco plant exposed to clipped sag ebrush, *a tobacco plant loaded with tobacco *a plant exposed to both sag ebrush and hornworms. The da m ag e and compounds from the hornworms' saliva trigger plants to produce
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This note was uploaded on 07/23/2008 for the course BIOLOGY bio 1a03 taught by Professor Dudley during the Spring '08 term at McMaster University.

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Complete Dudley Notes (including lectures) - BIO 1AA3...

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