Temporal shifts in iso/anisohydry revealed from daily observations of plant water potential in a dominant desert shrub
Temporal shifts in iso/anisohydry revealed from daily observations of plant water potential in a dominant desert shrub
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DOI：
10.1111/nph.16196
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发表时间：
2019-10-28
期刊：
影响因子：
9.4
通讯作者：
Ogle, Kiona
中科院分区：
文献类型：
--
作者：
Guo, Jessica S.;Hultine, Kevin R.;Ogle, Kiona
根据植物对水势（psi）的调节，植物具有从等水到各向异性的特征，但水力策略的可塑性在很大程度上是未知的。环境驱动因素的作用在Larrea tridentata的水力行为进行了评估，Larrea tridentata是一种耐旱的沙漠灌木，能够承受广泛的环境条件。利用1.5年2324个每日黎明前和正午psi现场测量的时间序列，探讨了水力行为与土壤水供应、大气需求和温度之间的时间变化。Larrea的水力行为是高度动态的，从部分等水到极端各向异性。在高生产力时期，湿润土壤条件下，Larrea表现出极端的各向异性，而在长时间的干旱或寒冷条件下，生产力较低时，Larrea表现出部分等水分。环境条件可以在相对较快的时间尺度上强烈影响植物的水力行为，这增强了我们对植物干旱响应的理解。虽然物种可能表现出主导的水力行为，但可变的环境条件可以促进psi调节的可塑性，特别是对于季节性干燥气候中的物种。
Plant species are characterized along a spectrum of isohydry to anisohydry depending on their regulation of water potential (psi), but the plasticity of hydraulic strategies is largely unknown. The role of environmental drivers was evaluated in the hydraulic behavior of Larrea tridentata, a drought-tolerant desert shrub that withstands a wide range of environmental conditions. With a 1.5 yr time-series of 2324 in situ measurements of daily predawn and midday psi, the temporal variability of hydraulic behavior was explored in relation to soil water supply, atmospheric demand and temperature. Hydraulic behavior in Larrea was highly dynamic, ranging from partial isohydry to extreme anisohydry. Larrea exhibited extreme anisohydry under wet soil conditions corresponding to periods of high productivity, whereas partial isohydry was exhibited after prolonged dry or cold conditions, when productivity was low. Environmental conditions can strongly influence plant hydraulic behavior at relatively fast timescales, which enhances our understanding of plant drought responses. Although species may exhibit a dominant hydraulic behavior, variable environmental conditions can prompt plasticity in psi regulation, particularly for species in seasonally dry climates.