DISSERTATION RESEARCH: Plant response to water availability and drought in a changing world

在过去的60年里，全球干旱的频率和严重程度都在增加，预计这种增加将在未来几十年继续下去。极端干旱事件已经对世界各地的树木和其他木本植物造成了损害，导致了广泛的森林死亡。随着温室气体排放量在全球范围内持续上升，森林的重要性日益增加，因为树木可以吸收二氧化碳并以木材的形式储存几个世纪。然而，干旱期间树木的死亡减少了可吸收的量，并增加了死树腐烂时释放回空气中的二氧化碳量。这项博士论文改进基金将提供资金来评估哪种植物更容易受到干旱的影响，以及决定植物的机制？易受极端干旱事件影响。这项研究有可能揭示木本植物或多或少耐干旱的特征，并可能提高预测物种的能力。应对极端干旱事件。研究结果将使当地的土地管理者和决策者了解哪些树种对干旱的耐受性更强，从而改进森林恢复和管理计划，以应对日益严重的干旱。本项目将采用新颖的方法，利用植物解剖特征和生理测量来确定木本植物对极端干旱的抗性。干旱导致树木死亡的主要原因是植物的导水管中的栓子堆积，阻碍了水分从土壤向上到叶子的适当流动。研究人员将研究哪些解剖特征使植物更容易发生栓塞。这项工作将在干燥和潮湿的温带和热带森林中进行，以提供在不同降雨环境下生长的植物如何对干旱作出反应的信息。该项目将包括为哥斯达黎加西北部农村地区的公立小学教师举办讲习班，该地区历史上曾发生过极端干旱，导致森林大面积死亡。这些讲习班将通过积极学习植物如何获取和利用水分以及干旱对原生森林的影响来加强哥斯达黎加小学课程。

Drought has been increasing in frequency and severity worldwide for the last 60 years, and the increase is expected to continue over the next several decades. Extreme drought events are already taking their toll on trees and other woody plants all over the world, leading to widespread forest mortality. As greenhouse gas emissions continue to rise on a global scale, the importance of forests increases, as trees can take up carbon dioxide and store it for centuries in the form of wood. However, the death of trees during drought reduces how much can be taken up and increases the amount of carbon dioxide released back into the air when dead trees decompose. This Doctoral Dissertation Improvement Grant will provide funds to evaluate which kinds of plants are more susceptible to drought, and the mechanisms that determine plants? vulnerability to extreme drought events. This research has the potential to reveal characteristics that make woody plants more or less tolerant to drought and may increase the ability to predict species? responses to extreme drought events. The results will inform local land managers and policy-makers on which tree species are more tolerant to drought and therefore improve plans for restoration and management of forests in the face of increasing drought severity. This project will use novel methods to determine the resistance of woody plants to extreme drought using plant anatomical features and physiological measurements. The major cause of tree mortality from drought is embolism accumulation in the water-conducting pipes of plants that obstruct proper water movement from the soil up to the leaves. The researchers will study which anatomical traits make plants more susceptible to embolisms. This work will be conducted in both dry and wet temperate and tropical forests to provide information on how plants growing under different rainfall environments respond to drought. The project will include workshops with public primary school teachers in rural Northwestern Costa Rica, which is an area with a history of extreme droughts that have resulted in widespread forest mortality. These workshops will enhance Costa Rican primary school curriculum through active learning of how plants obtain and use water and the impact of drought on native forests.