University of Illinois Urbana-Champaign

Evolutionary response of plants to increased UV-B radiation: Greenhouse and field studies with Arabidopsis thaliana

Trumbull, Vernon Lyle

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Description

Title
Evolutionary response of plants to increased UV-B radiation: Greenhouse and field studies with Arabidopsis thaliana
Author(s)
Trumbull, Vernon Lyle
Issue Date
1996
Doctoral Committee Chair(s)
Paige, Ken N.
Department of Study
Biology
Discipline
Biology
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
  • Biology, Botany
  • Biology, Ecology
  • Biology, Plant Physiology
Language
eng
Abstract
  • Two approaches were used to examine the evolution of UV-B tolerance in Arabidopsis thaliana. In the first approach, I studied adaptation to past levels of UV-B radiation by examining the impact of enhanced UV-B radiation on two ecotypes of A. thaliana that originated from very different natural UV-B environments. The Libyan ecotype (from a high UV-B environment) showed no UV-B induced damage to rosette mass or the germination success of seeds harvested from irradiated plants. The Norwegian ecotype (from a low UV-B environment) showed a significant reduction in these variables in response to enhanced UV-B. The concentration of kaempferol, a putative UV-B protective filter, increased in the Libyan ecotype by 81% compared to a 22% increase in the Norwegian ecotype.
  • In the second approach, both greenhouse and field experiments were done to measure variation for UV-B sensitivity in a natural population of A. thaliana. This population consists of four morphologically and genetically discrete groups. There was no genetic variation for UV-B tolerance in two of the three greenhouse experiments. In the 1993-94 field study, we found genetic variation for UV-B sensitivity in this population. The high UV-B treatment caused a change in fruit number (relative to ambient UV-B) ranging from an increase of 30% (genotype B) to a decrease of 45% (genotype D). The seeds from this experiment were allowed to disperse naturally and a random sample of the F, rosettes were identified using RAPD markers. The relative frequency of genotype D in the F, generation was reduced by 34%. Given that genotype D comprises greater than 90% of this population, projected increases in solar UV-B may have significant consequences for the genetic structure of this population. However, evidence from the 1994-95 experiment indicates that UV-B selection may be variable between years. In this study, there was no genetic variation for UV-B sensitivity but the high UV-B treatment did cause an overall reduction in fruit number ($-$19%). This year to year variation in UV-B selection may act to maintain genetic variation for UV-B tolerance within this population.
Type of Resource
text
Permalink
http://hdl.handle.net/2142/22305
Copyright and License Information
Copyright 1996 Trumbull, Vernon Lyle

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