Jolly Amber R, Zailaa Joseph, Farah Ugbad, Woojuh Janty, Libifani Félicia Makaya, Arzate Darlene, Caranto Christian Alex, Correa Zayra, Cuba Jose, Calderon Josephina Diaz, Garcia Nancy, Gastelum Laura, Gutierrez Ivette, Haro Matthew, Orozco Monserrat, Pinlac Jessica Lamban, Miranda Andoni, Nava Justin, Nguyen Christina, Pedroza Edgar, Perdomo Jennyfer, Pezzini Scott, Yuen Ho, Scoffoni Christine
Department of Biological Sciences, California State University, Los Angeles, Los Angeles, CA, United States.
Front Plant Sci. 2021 Jan 8;11:578338. doi: 10.3389/fpls.2020.578338. eCollection 2020.
Different microclimates can have significant impact on the physiology of succulents that inhabit arid environments such as the Mojave Desert (California). We investigated variation in leaf physiology, morphology and anatomy of two dominant Mojave Desert monocots, (Joshua tree) and , growing along a soil water availability gradient. Stomatal conductance ( ) and leaf thickness were recorded in the field at three different sites (north-western slope, south-eastern slope, and alluvial fan) in March of 2019. We sampled leaves from three individuals per site per species and measured in the lab relative water content at the time of measurements, saturated water content, cuticular conductance, leaf morphological traits (leaf area and length, leaf mass per area, % loss of thickness in the field and in dried leaves), and leaf venation. We found species varied in their : while showed significantly higher in the alluvial fan than in the slopes, was highest in the south-eastern slope. The differences in did not relate to differences in leaf water content, but rather to variation in number of veins per mm in and leaf width in . Our results indicate that displays a higher water conservation strategy than . We discuss these differences and trends with water availability in relation to species' plasticity in morphology and anatomy and the ecological consequences of differences in 3-dimensional venation architecture in these two species.
不同的微气候会对生活在干旱环境（如加利福尼亚州莫哈韦沙漠）中的多肉植物的生理产生重大影响。我们研究了沿着土壤水分可利用性梯度生长的两种莫哈韦沙漠优势单子叶植物——短叶丝兰（约书亚树）和大果丝兰的叶片生理、形态和解剖结构的变化。2019年3月，在三个不同地点（西北坡、东南坡和冲积扇）的野外记录了气孔导度（gs）和叶片厚度。我们从每个物种每个地点的三株个体上采集叶片，并在实验室测量了测量时的相对含水量、饱和含水量、角质层导度、叶片形态特征（叶面积和长度、单位面积叶质量、田间和干燥叶片厚度的损失百分比）以及叶脉。我们发现物种间的气孔导度存在差异：虽然大果丝兰在冲积扇的气孔导度显著高于在山坡上的，短叶丝兰在东南坡的气孔导度最高。气孔导度的差异与叶片含水量的差异无关，而是与大果丝兰每毫米叶脉数量和短叶丝兰叶片宽度的变化有关。我们的结果表明，短叶丝兰比大果丝兰表现出更高的水分保持策略。我们结合物种在形态和解剖结构上的可塑性以及这两个物种三维叶脉结构差异的生态后果，讨论了这些与水分可利用性相关的差异和趋势。
