Event Title

Growth as a mechanism of defense in Phaseolus lunatus

Presenter Information

Kaitlyn Musser

Faculty Advisor

Dr. Alissa Packer

Start Date

24-4-2018 5:00 PM

End Date

24-4-2018 6:00 PM

Description

Plants use mechanisms of defense to combat herbivory. Extrafloral nectary (EFN) production is a form of defense present in lima bean (Phaseolus lunatus) which is positively correlated with herbivory. The plant produces nectar through EFNs which attracts the enemy of the herbivore trading food for protection. However, plants have limited resources, so they must allocate energy to their best bet of fitness. This explains why heavily damaged plants may allocate to another defense mechanism or to growth instead. In vining plants, it is common to use growth as a foraging method. For example, plants grow towards sunlight in a dark environment to increase the sunlight they receive. In this likeness, it is interesting to consider growth to evade herbivory as a defense mechanism. If Phaseolus lunatus invest in growth to evade herbivory, a high degree of herbivory damage would result in them having less EFNs and higher internode lengths than a those experiencing a low degree of herbivory. This phenomenon was tested by an 8-week experimental study in which Phaseolus lunatus was damaged in four treatments: 0%, 20%, 50%, and 80% and the internode lengths, height, leaf number, and EFN numbers were measured before and after damage. From this experiment, the idea of growth as a form of defense was supported by lower EFN numbers per leaf and higher internode lengths in the 50 and 80% damage groups when compared to the EFN numbers per leaf in the 0 and 20% damage groups.

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Apr 24th, 5:00 PM Apr 24th, 6:00 PM

Growth as a mechanism of defense in Phaseolus lunatus

Plants use mechanisms of defense to combat herbivory. Extrafloral nectary (EFN) production is a form of defense present in lima bean (Phaseolus lunatus) which is positively correlated with herbivory. The plant produces nectar through EFNs which attracts the enemy of the herbivore trading food for protection. However, plants have limited resources, so they must allocate energy to their best bet of fitness. This explains why heavily damaged plants may allocate to another defense mechanism or to growth instead. In vining plants, it is common to use growth as a foraging method. For example, plants grow towards sunlight in a dark environment to increase the sunlight they receive. In this likeness, it is interesting to consider growth to evade herbivory as a defense mechanism. If Phaseolus lunatus invest in growth to evade herbivory, a high degree of herbivory damage would result in them having less EFNs and higher internode lengths than a those experiencing a low degree of herbivory. This phenomenon was tested by an 8-week experimental study in which Phaseolus lunatus was damaged in four treatments: 0%, 20%, 50%, and 80% and the internode lengths, height, leaf number, and EFN numbers were measured before and after damage. From this experiment, the idea of growth as a form of defense was supported by lower EFN numbers per leaf and higher internode lengths in the 50 and 80% damage groups when compared to the EFN numbers per leaf in the 0 and 20% damage groups.