Date of Award

2019

Document Type

Thesis

Degree Name

Bachelors

Department

Natural Sciences

First Advisor

Oberle, Brad

Area of Concentration

Biology

Abstract

Tillandsia utriculata is an ecologically important epiphytic bromeliad that is native to Florida. These plants have unique ways of absorbing nutrients and responding to the stressors that come along with occupying a particularly stressful niche (growing on the bark of trees). A major adaptation that this study focused on is the growth form of these plants’ leaves, referred to as “tanking”. Tanking allows for the collection of detritus and water in the base of these plants leaves to be stored and used in times of drought. From a pilot study, there is reason to believe that there is some kind of logistic growth form in T. utriculata plants when a plant transitions to this “tanking” form, and this study aims to answer questions of how this change in growth rate can be quantified by looking further into the mechanisms by which T. utriculata absorbs limiting nutrients that are crucial to their survival, namely nitrogen in the form of nitrate (NO -3). It was predicted that there would be a spike in growth somewhere in the plant’s life, and that there would be an increase of the amount of nutrients that could be absorbed by the base of leaf (where the “tank” is located). To do this, growth rates of an in situ population of T. utriculata in Sarasota, FL were measured over the course of a 4-month time period. In addition, nutrient absorption assays were taken, using conductivity to quantify the nutrients that were being absorbed by tip and base leaf segments of different size classes of T. utriculata plants. It was found that there is evidence of some kind of change in the growth and nutrient absorption in the plant’s transition from juvenile to adult, but in ways that were not predicted. These findings have implications having to do with heteroblasty in the species, ex situ conservation, and the ways that we understand the anatomical changes that come along with growth in Tillandsia utriculata.

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