Harvey, Alan , Shiflett, Allison .
Rapid activation of extrafloral nectaries induced by minimal damage in Chinese Tallow (Triadica sebifera).
Extrafloral nectaries (EFNs) are nectar-secreting structures that function to attract not pollinators, but rather bodyguards (usually aggressive ants) that will attack herbivores. Few plant species are known to have EFNs that are inducible (i.e., triggered by herbivore attack). This may be because induced EFNs are constrained by not only the inevitable lag time between the trigger and the plantís induced response, but also a second lag time, between the induced response and the recruitment of ants to the nectaries. In this study, we measured the response time of EFNs to leaf damage in Chinese Tallow (Triadica sebifera). We used a hole punch to damage leaves of Chinese Tallow trees in the field, and subsequently monitored EFNs for signs of nectar activity on an hourly basis. Although leaves experienced minimal damage (< 2% mean leaf tissue removal), nectar production was visibly initiated in nearly all leaves within 3-6 hours of damage. Within this limited span, response time varied significantly among trees, but was not affected by tree size, leaf size, or local light intensity. This is the first study to measure the lag time between damage and response in an inducible EFN, making generalizations difficult. However, the speed of this response compares favorably with that of other types of rapidly induced defenses. This suggests that EFNs in Chinese Tallow may be able to target the individual herbivores that triggered the response as well as herbivores that visit the plant later, depending on how quickly ants recruit to the activated nectaries and how long nectar production continues.
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1 - Georgia Southern University, Biology, P.O. Box 8042, Statesboro, GA, 30460, USA
Presentation Type: Oral Paper:Papers for Sections
Location: 555B/Convention Center
Date: Tuesday, August 3rd, 2010
Time: 8:45 AM