Departamento de Suelos y Riegos, Instituto Canario de Investigaciones Agrarias (ICIA), Ctra de El boquerón s/n. 38270. San Cristóbal de La Laguna, Tenerife, Canary Islands, Spain.
Forest Systems, Scion, PO Box 29237, Christchurch, 8440, New Zealand.
Plant Cell Environ. 2019 Feb;42(2):717-729. doi: 10.1111/pce.13460. Epub 2018 Nov 19.
Stomatal regulation is crucial for forest species performance and survival on drought-prone sites. We investigated the regulation of root and shoot hydraulics in three Pinus radiata clones exposed to drought stress and its coordination with stomatal conductance (g ) and leaf water potential (Ψ ). All clones experienced a substantial decrease in root-specific root hydraulic conductance (K ) in response to the water stress, but leaf-specific shoot hydraulic conductance (K ) did not change in any of the clones. The reduction in K caused a decrease in leaf-specific whole-plant hydraulic conductance (K ). Among clones, the larger the decrease in K , the more stomata closed in response to drought. Rewatering resulted in a quick recovery of K and g . Our results demonstrated that the reduction in K , attributed to a down regulation of aquaporin activity in roots, was linked to the isohydric stomatal behaviour, resulting in a nearly constant Ψ as water stress started. We concluded that higher K is associated with water stress resistance by sustaining a less negative Ψ and delaying stomatal closure.
气孔调节对于耐旱生境中森林物种的性能和生存至关重要。我们研究了在遭受干旱胁迫时，三种辐射松无性系的根和茎水力调节及其与气孔导度（g）和叶片水势（Ψ）的协调关系。所有无性系的根比根水力传导度（K）都显著降低，以应对水分胁迫，但在任何无性系中，叶比茎水力传导度（K）都没有变化。K 的降低导致叶片比整株水力传导度（K）降低。在无性系中，K 降低越大，气孔对干旱的关闭程度越大。复水后，K 和 g 迅速恢复。我们的结果表明，K 的降低归因于根系水通道蛋白活性的下调，与等水力的气孔行为有关，导致在水分胁迫开始时，Ψ几乎保持不变。我们得出的结论是，较高的 K 通过维持较低的负 Ψ 和延迟气孔关闭与抗水胁迫有关。
