Bartlett Megan K, Klein Tamir, Jansen Steven, Choat Brendan, Sack Lawren
Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA 90095;
Department of Plant and Environmental Sciences, Weizmann Institute of Science, 76100 Rehovot, Israel.
Proc Natl Acad Sci U S A. 2016 Nov 15;113(46):13098-13103. doi: 10.1073/pnas.1604088113. Epub 2016 Nov 2.
Climate change is expected to exacerbate drought for many plants, making drought tolerance a key driver of species and ecosystem responses. Plant drought tolerance is determined by multiple traits, but the relationships among traits, either within individual plants or across species, have not been evaluated for general patterns across plant diversity. We synthesized the published data for stomatal closure, wilting, declines in hydraulic conductivity in the leaves, stems, and roots, and plant mortality for 262 woody angiosperm and 48 gymnosperm species. We evaluated the correlations among the drought tolerance traits across species, and the general sequence of water potential thresholds for these traits within individual plants. The trait correlations across species provide a framework for predicting plant responses to a wide range of water stress from one or two sampled traits, increasing the ability to rapidly characterize drought tolerance across diverse species. Analyzing these correlations also identified correlations among the leaf and stem hydraulic traits and the wilting point, or turgor loss point, beyond those expected from shared ancestry or independent associations with water stress alone. Further, on average, the angiosperm species generally exhibited a sequence of drought tolerance traits that is expected to limit severe tissue damage during drought, such as wilting and substantial stem embolism. This synthesis of the relationships among the drought tolerance traits provides crucial, empirically supported insight into representing variation in multiple traits in models of plant and ecosystem responses to drought.
气候变化预计会使许多植物遭受更严重的干旱，这使得耐旱性成为物种和生态系统响应的关键驱动因素。植物的耐旱性由多种性状决定，但无论是在单株植物内部还是跨物种之间，这些性状之间的关系尚未针对植物多样性的一般模式进行评估。我们综合了已发表的关于262种木质被子植物和48种裸子植物的气孔关闭、萎蔫、叶、茎和根的水力传导率下降以及植物死亡率的数据。我们评估了跨物种耐旱性状之间的相关性，以及单株植物中这些性状的水势阈值的一般顺序。跨物种的性状相关性为从一两个采样性状预测植物对广泛水分胁迫的反应提供了一个框架，提高了快速表征不同物种耐旱性的能力。对这些相关性的分析还发现，叶和茎的水力性状与萎蔫点或膨压丧失点之间存在相关性，这超出了仅由共同祖先或与水分胁迫的独立关联所预期的范围。此外，平均而言，被子植物物种通常表现出一系列耐旱性状，这些性状预计会在干旱期间限制严重的组织损伤，如萎蔫和大量的茎干栓塞。对耐旱性状之间关系的这种综合分析为在植物和生态系统对干旱的响应模型中表示多个性状的变化提供了关键的、基于实证的见解。
