Root lateral interactions drive water uptake patterns under water limitation
Root lateral interactions drive water uptake patterns under water limitation
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DOI：
10.1016/j.advwatres.2021.103896
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发表时间：
2021-04-14
影响因子：
4.7
通讯作者：
Ivanov, Valeriy
中科院分区：
文献类型：
--
作者：
Agee, Elizabeth;He, Lingli;Ivanov, Valeriy
根系吸水的可塑性决定了水分限制和干旱期间蒸腾作用的维持。然而，植物水分吸收的机制基础，以及在个人和生态系统尺度上的水分吸收策略的影响仍然难以捉摸。我们的三维模型根吸水饱和条件下的一公顷的温带森林地块的生长季节与一个明显的中期干旱期。根结构，水力特性和根系之间的横向相互作用程度的变化产生不同的本地响应水分限制，并提供个人和社区对气象条件的反应的见解。结果表明，表面干燥，相互作用的根转移区域的积极吸收更深层次的土壤层，不太丰富的根生物量的生态系统尺度响应的可塑性。这些变化是根系和土壤水力特性共同作用的结果，说明了根系和土壤水力学在确定植物水分来源方面的密切联系。我们进一步证明，根的横向相互作用是有益的，在生态系统的规模，即使树木竞争水分。具体而言，一个空间上更广泛的根系有利于获得一个更大的土壤水库，往往改善水的限制和减少尖锐的水势梯度。虽然减少水分胁迫是一个好处，但它可以被与更大的生根系统相关的增加的根系建设和维护成本所抵消。似是而非？可行性？因此，在竞争压力和根系生产成本被潜在的水效益所平衡的地方，暗示着根系群落共存的区域。
The plasticity of root water uptake determines the maintenance of transpiration during periods of water limitation and drought. However, the mechanistic basis of plant water uptake, as well as the implications of water uptake strategies at the individual and ecosystem scale remain elusive. We model three-dimensional root water uptake under variably saturated conditions for a one-hectare temperate forest plot for a growing season with a pronounced mid-season dry period. Variations in root architecture, hydraulic properties, and degree of lateral interaction between root systems produce divergent local responses to water limitation and provide insights on individual and community response to meteorological conditions. Results demonstrate the plasticity of ecosystem scale responses to surface drying, where interacting roots shift regions of active uptake to deeper soil layers with less abundant root biomass. These shifts, a product of both root system and soil hydraulic properties, illustrate intimate links between root and soil hydraulics in determining plant water sourcing. We further demonstrate that root lateral interactions are beneficial at the ecosystem-scale, even when trees compete for water. Specifically, a more spatially extensive root system facilitates access to a larger soil water reservoir, often ameliorating water limitation and reducing sharp water potential gradients. While the reduction of water stress is a benefit, it can be offset by increased root construction and maintenance costs associated with the larger rooting system. A plausible ?viability ? region of root communal co-existence is therefore implied where competitive pressures and root production costs are balanced by a potential water benefit.