Stomatal regulation and xylem hydraulics of limber pine and Engelmann spruce in Great Basin sky-island ecosystems
Stomatal regulation and xylem hydraulics of limber pine and Engelmann spruce in Great Basin sky-island ecosystems
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DOI：
10.1016/j.scitotenv.2023.164351
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发表时间：
2023-06-03
影响因子：
9.8
通讯作者：
Biondi，Franco
中科院分区：
文献类型：
--
作者：
Liu，Xinsheng;Ziaco，Emanuele;Biondi，Franco
植物气孔调节和木质部水力学的结合对于预测植物对干旱胁迫的响应具有重要意义。然而，气孔和水力性状的种内变异，以及这些变异如何相互作用，仍然在很大程度上是未知的。我们假设干旱可以减少气孔调节，但增加木质部水力安全，导致物种内的气孔水力协调。我们估计的敏感性，全树冠层电导土壤干燥与木质部水力特性的两个优势针叶树，即软松（柔枝松）和云杉（云杉）。我们的研究是在连续五年（2013-2017年）在内华达州生态水文评估网络（NevCAN）的三个不同海拔的仪器站点进行的，这些站点位于大盆地天空岛生态系统中。这两种针叶树在低海拔土壤干燥的气孔敏感性降低，表明积极的气孔适应干旱。而柔软的松树增加木质部栓塞阻力平行减少气孔敏感性土壤干燥，相反的液压调整，检测到在Engelmann云杉。我们的研究结果提供的证据表明，成熟的树木可以响应气候变化，气孔调节和木质部水力学的协调变化，但这种变化可以不同的内部和物种之间的方式，需要使用原位数据进行检查。破译种内变异的全植物气孔和水力性状最终有助于确定耐旱性和脆弱性，特别是对栖息在广泛的景观树种。
Integration of whole-plant stomatal regulation and xylem hydraulics is of critical importance for predicting species response to drought stress. Yet intraspecific variability of stomatal and hydraulic traits, and how these variabilities interact, remain largely unknown. We hypothesized that drought can drive less stomatal regulation but increase xylem hydraulic safety, resulting in stomatal-hydraulic coordination within a species. We estimated sensitivity of whole-tree canopy conductance to soil drying together with xylem hydraulic traits of two dominant conifers, i.e. limber pine (Pinus flexilis) and Engelmann spruce (Picea engelmannii). Our study was conducted using sub-hourly measurements over five consecutive years (2013–2017) at three instrumented sites with different elevations within the Nevada Eco-hydrological Assessment Network (NevCAN) in Great Basin sky-island ecosystems. Both conifers showed a reduction of stomatal sensitivity to soil drying at lower elevations, indicating an active stomatal acclimation to drought. While limber pine increased xylem embolism resistance in parallel with reduced stomatal sensitivity to soil drying, an opposite hydraulic adjustment was detected in Engelmann spruce. Our results provide evidence that mature trees can respond to climatic changes using coordinated shifts in stomatal regulation and xylem hydraulics, but such changes can differ within and between species in ways that need to be examined using in situ data. Deciphering intraspecific variability in whole-plant stomatal and hydraulic traits ultimately contributes to defining drought tolerance and vulnerability, particularly for tree species that inhabit a wide range of landscapes.