Departamento de Ecología, Universidad de Granada, 18071 Granada, Spain.
Departamento de Ecología, Universidad de Granada, 18071 Granada, Spain.
Sci Total Environ. 2022 Jul 20;831:154797. doi: 10.1016/j.scitotenv.2022.154797. Epub 2022 Mar 25.
Predicted hotter and drier climatic conditions in the Mediterranean Basin will probably hamper current afforestations and reforestations by negatively influencing tree performance. Understanding how saplings can adjust their physiology to shortages in water availability is essential to predict early-stage success of forest ecological restoration. Pines are common target species used in afforestations and reforestations; however, the capacity of their saplings for physiological plasticity to promote drought tolerance remains largely unexplored. In this study, we evaluated the demographical and resource-use consequences of short-term irrigation among four pine species (Pinus halepensis, Pinus pinea, Pinus nigra and Pinus sylvestris) growing under water-limiting conditions in a common garden experiment. Summer irrigation increased the survival rate of those pines that were suffering from hydric stress under the xeric conditions of the common garden (i.e. P. pinea, P. nigra and P. sylvestris). Moreover, short-term water supplementation slightly enhanced aboveground biomass production across species. However, leaf isotopic composition and nutrient concentrations did not change after summer irrigation. Independently of water supplementation, P. halepensis was the best adapted species to water scarcity and showed the best physiological and growth performance. By contrast, P. pinea, P. nigra and P. sylvestris saplings exhibited drought-induced reductions in stomatal conductance and low water-use efficiency, nutrient deficiency, and severe N:P and N:K stoichiometric imbalances, leading to impaired growth. We conclude that the lack of physiological plasticity of water-stressed pine saplings to withstand the impacts of climate aridification will likely cause severe impairment of their nutrient status, growth and survival, with dire implications for the successful establishment of Mediterranean afforestation and reforestation programs.
预测地中海盆地气候条件将变得更加炎热干燥，这可能会通过负面影响树木表现而阻碍当前的造林和再造林活动。了解幼苗如何调整其生理机能以适应水分供应不足的情况，对于预测森林生态恢复的早期成功至关重要。松树是造林和再造林中常用的目标物种；然而，其幼苗在促进耐旱性方面的生理可塑性的能力在很大程度上仍未得到探索。在这项研究中，我们评估了在水限制条件下，四种松树（Pinus halepensis、Pinus pinea、Pinus nigra 和 Pinus sylvestris）在一个共同花园实验中进行短期灌溉的人口统计学和资源利用后果。夏季灌溉提高了在共同花园干旱条件下遭受水分胁迫的那些松树的存活率（即 P. pinea、P. nigra 和 P. sylvestris）。此外，短期补水略微提高了跨物种的地上生物量生产。然而，叶片同位素组成和养分浓度在夏季灌溉后没有变化。独立于水分补充，P. halepensis 是最能适应水分短缺的物种，表现出最佳的生理和生长性能。相比之下，P. pinea、P. nigra 和 P. sylvestris 的幼苗表现出干旱诱导的气孔导度降低、低水分利用效率、养分缺乏以及严重的 N:P 和 N:K 化学计量失衡，导致生长受损。我们得出结论，受水分胁迫的松树幼苗缺乏应对气候变干影响的生理可塑性，这可能导致其养分状况、生长和存活严重受损，对地中海造林和再造林计划的成功实施产生严重影响。
