U.S.-Chile Dissertation Enhancement: Making Dew in the Atacama; Extreme Drought Tolerance and Salt Utilization of Nolana Flaccida (Solanaceae) in the Atacama Desert of Chile

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9901329Holbrook This award funds a Dissertation Enhancement Grant for Matthew V. Thompson, Harvard University, under the direction of Dr. Noel M. Holbrook, for a study on the mechanism of drought tolerance of Nolana flaccida, a plant native to the Atacama Desert of Chile, considered the driest place in the world. This perennial shrub can survive decade-long periods without rain, thriving and flowering while individuals of other species (except cacti) lie dead or dormant. The only two main sources of water for the plants in this region are the rain water immediately following ENSO events (El Nino Southern Oscillation), and water derived from thermal vapor diffusion during periods of extended drought, which sometimes last for ten years. The study will address the mechanisms by which the Nolana flaccida plant is able to survive in this inhospitable environment. The two hypotheses to be tested will be centered on the soil processes that provide water to the plants in this system, and on the use of salt by the plant to improve the water use of its leaves. In addition, to tie these two processes together, they will look at the rate of delivery of salt through the plant, its natural concentration in the soil at various depths, and how fast it must be delivered to be maintained at the high concentrations found.The study of this model system will add to the array of adaptations employed by desert plants, and could make significant contributions to our understanding of basic phenomena in soil physics.