Hansika Herath: Intraspecific Variation of Acquired Thermotolerance in the Liverwort Marchantia Inflexa

Abstract Increasing global temperature threatens plant productivity and ecological stability. Some plants can survive heat stress and still maintain their performance. Surviving heat stress varies among and within plant species. While intraspecific variation in heat stress tolerance exists, it is rarely studied, and such studies can elucidate the underlying molecular mechanisms that can be used to improve crop thermotolerance and for in-situ and ex-situ species conservation. A tropical liverwort, Marchantia inflexa will be used here to examine the intraspecific variation of heat stress tolerance and sex differences in tolerance. Populations growing in natural and novel habitats in the island Trinidad will be targeted in this study to test for variation in heat tolerance. Field-collected samples will be cultivated in common garden conditions, harvested, and tested for heat stress tolerance. Data will be collected on traits associated with heat stress including photosynthetic traits, chlorophyll fluorescence, chlorophyll content, and membrane thermostability. Findings of this study will enhance the existing body of knowledge on variation in heat stress tolerance within a plant species. Key words: Marchantia inflexa, Heat stress, Sex differences, Acclimation, Thermotolerance