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. 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 tree communal co-existence is therefore implied where competitive pressures and root production costs are balanced by a potential water benefit.

水分吸收和干旱期间，根系水分吸收的可塑性决定了蒸腾作用的维持。但是，植物吸水的机理基础以及吸水策略在个体和生态系统范围内的含义仍然难以捉摸。我们对一公顷温带森林地在一个生长季具有明显的中期干旱期的可变饱和条件下的三维根系水分吸收进行建模。根系结构，水力特性以及根系之间的横向相互作用程度的变化产生了对水分限制的不同局部响应，并提供了有关个人和社区对气象条件响应的见解。结果表明，生态系统规模对表面干燥的响应具有可塑性，相互作用的根部将活跃的吸收区域转移到根部生物量较少的较深土壤层。我们进一步证明，即使树木争夺水，根的横向相互作用在生态系统范围内也是有益的。具体而言，空间上更广泛的根系有助于访问更大的土壤水库，通常可以改善水的限制并降低尖锐的水势梯度。虽然减少水分胁迫是有益的，但可以通过与较大的生根系统相关的增加的根部建设和维护成本来抵消水分胁迫。因此，在竞争压力和根系生产成本与潜在水利之间取得平衡的情况下，暗示了树木社区共存的“可行”区域。我们进一步证明，即使树木争夺水，根的横向相互作用在生态系统范围内也是有益的。具体而言，空间上更广泛的根系有助于访问更大的土壤水库，通常可以改善水的限制并降低尖锐的水势梯度。虽然减少水分胁迫是有益的，但可以通过与较大的生根系统相关的增加的根部建设和维护成本来抵消水分胁迫。因此，在竞争压力和根系生产成本与潜在水利之间取得平衡的情况下，暗示了树木社区共存的“可行”区域。我们进一步证明，即使树木争夺水，根的横向相互作用在生态系统范围内也是有益的。具体而言，空间上更广泛的根系有助于访问更大的土壤水库，通常可以改善水的限制并降低尖锐的水势梯度。虽然减少水分胁迫是有益的，但可以通过与较大的生根系统相关的增加的根部建设和维护成本来抵消水分胁迫。因此，在竞争压力和根系生产成本与潜在水利之间取得平衡的情况下，暗示了树木社区共存的“可行”区域。通常可以改善水的限制，并降低尖锐的水势梯度。虽然减少水分胁迫是有益的，但可以通过与较大的生根系统相关的增加的根部建设和维护成本来抵消水分胁迫。因此，在竞争压力和根系生产成本与潜在水利之间取得平衡的情况下，暗示了树木社区共存的“可行”区域。通常可以改善水的限制，并降低尖锐的水势梯度。虽然减少水分胁迫是有益的，但可以通过与较大的生根系统相关的增加的根部建设和维护成本来抵消水分胁迫。因此，在竞争压力和根系生产成本与潜在水利之间取得平衡的情况下，暗示了树木社区共存的“可行”区域。