Abstract Detail

Recent Topics Posters

Rojas, Ana [1].

Estimating the climatic tolerances of tropical plant species.

Climate change modeling effects on tropical species is key to understanding how to save these bio diverse regions. Two functional traits in plants that have not been addressed as much especially in correlation to each other is drought and heat tolerance, both climatic conditions expected to increase in the tropics. For that eleven understory tropical palm species were studied from leaf samples collected in FIU and Fairchild Tropical Botanic Garden. Heat tolerance was conducted by immersing samples in heated baths within the range of 46°-50°C. Their photosynthetic performance after the heating was measured by obtaining the dark-adapted chlorophyll fluorescence value (Fv/Fm). The photosynthetic threshold was the temperature in which half the initial value (Fv/Fm), given a baseline of 0.800 for all species, was measured at, i.e. 0.400, this was the Critical Thermal Maximum (CT Max) temperature. The CT Max for the 11 species was in the range of 50.5°- 55° C. Drought tolerance was done by immersing samples in a polyethylene glycol solution to increase osmotic stress and calculating the percent damage from conductivity measurements, giving a range of 24 -81%. These two data sets were graphed (CT Max vs. Drought Percent Damage) and demonstrated significantly low fitted line (r²=0.04817). Thus there is a correlation between the two traits but not causation for one another, which is to be expected. Next the average optimum temperature was extracted from a worldwide Internet database, GBIF, and graphed against the CT Max of each species. This graph demonstrated a moderate positive fitted line (r²=0.28874). Interpretation shows that a low CT Max correlated with a low average optimum temperature thus a species inhabiting lower temperature areas has a lower threshold than one in areas with higher temperatures. Based upon the results of the first graph we cannot deduce that heat and drought tolerance are correlated but on the second graph we can say that tolerance is influenced by a species surrounding natural environment. These results suggest a need for greater understanding of tropical species in terms of climate change modeling in hopes to reduce anthropogenic effects.

1 - Florida International University, Department Of Biological Sciences, 11200 SW 8th St, Miami, FL, 33199, USA

Keywords:
Tropical plants
climatic tolerances
thresholds
drought
heat.

Presentation Type: Recent Topics Poster
Session: P, Recent Topics Posters
Location: Exhibit Hall/Savannah International Trade and Convention Center
Date: Monday, August 1st, 2016
Time: 5:30 PM
Number: PRT008
Abstract ID:1176
Candidate for Awards:None