Abstract Detail

Symbioses: Plant, Animal, and Microbe Interactions

Jones, Ian [1].

Temporal and developmental changes in extrafloral nectar production in Senna mexicana var. chapmanii: is extrafloral nectar an inducible defense?

Extrafloral nectar (EFN) mediates food for protection mutualisms between plants and defensive insects, predominantly ants. A large body of evidence supports the role of ants as plant protectors, and their presence has been observed to reduce herbivory, and increase reproductive fitness in a number of plant species. Interactions with ants do not always benefit plants, however, and few studies have considered how ant-plant mutualisms might vary temporally both in number and in outcome. My research explores the physiology of EFN production in Senna mexicana var. chapmanii, a legume native to the pine rockland habitats of south Florida. Greenhouse experiments aim to establish how EFN production in S. chapmanii varies diurnally and how simulated herbivory affects the plant’s overall investment in EFN. Finally we aim to determine how these dynamics change with plant age.
Sixty S. chapmanii plants will be grown from seeds and divided randomly into treatment and control groups. In the treatment plants, 50% leaf damage will be inflicted on the five youngest open leaves, using scissors. The total volume and sugar concentration of nectar accumulated on these five leaves, and from equivalent leaves in the control group, will be measured at 7am and 7pm every day for 5 days, with baseline measurements starting 1 day prior to damage treatments. This experiment will be repeated at three plant developmental stages. We hypothesize that S. chapmanii will produce more EFN during the night than during the day, and that nectar production will be increased in response to leaf damage. Furthermore we predict that baseline per-nectary production of EFN will be negatively correlated with plant age.
Preliminary results strongly support the first two hypotheses. Overall EFN production was 282% higher at night than during the day, and nectar production is significantly increased in response to leaf damage, peaking in the 24 hours post treatment.

Broader Impacts:

1 - Florida International University, Biological Sciences, 760 Euclid Avenue, appartment 104, Miami Beach, FL, 33139, USA

Keywords:
extrafloral nectar
plant defense
Senna Mexicana var. chapmanii
ant-plant interactions.

Presentation Type: Oral Paper:Papers for Topics
Session: 8
Location: Prince of Wales/Riverside Hilton
Date: Monday, July 29th, 2013
Time: 9:45 AM
Number: 8007
Abstract ID:162
Candidate for Awards:None