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

小行星9901329 该奖项为哈佛大学的马修·V·汤普森博士在诺埃尔·M. Holbrook，用于研究Nolana flaccida的耐旱机制，Nolana flaccida是一种原产于智利阿塔卡马沙漠的植物，被认为是世界上最干燥的地方。这种多年生灌木可以在没有雨水的情况下存活十年之久，在其他物种（仙人掌除外）死亡或休眠的情况下茁壮成长并开花。 这一地区植物仅有的两个主要水源是紧接着ENSO事件（厄尔尼诺南方涛动）之后的雨水，以及在长期干旱期间（有时持续十年）来自热蒸汽扩散的水。这项研究将解决Nolana flaccida植物能够在这种恶劣环境中生存的机制。 这两个假设将被测试集中在土壤过程中，提供水的植物在这个系统中，并在使用盐的植物，以提高其叶片的水分利用。此外，为了将这两个过程联系在一起，他们将研究盐通过植物的输送速率，其在不同深度土壤中的自然浓度，以及必须以多快的速度输送才能保持在所发现的高浓度。对这个模型系统的研究将增加沙漠植物所采用的适应性阵列，并可能对我们理解土壤物理学的基本现象做出重大贡献。

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.