Analyzing differences in tolerance to drought in Quercus spp., and the characterization of these responses at the species and individual population level, are imperative for the selection of resilient elite genotypes in reforestation programs. The main objective of this work was to evaluate differences in the response and tolerance to water shortage under in five Quercus spp. and five Andalusian Q. ilex populations at the inter- and intraspecies level. Six-month-old seedlings grown in perlite were subjected to drought treatments by withholding water for 28 days under mean 37 °C temperature, 28 W m-2 solar irradiance, and 41% humidity. The use of perlite as the substrate enabled the establishment of severe drought stress with reduction in water availability from 73% (field capacity) to 28% (dryness), corresponding to matric potentials of 0 and −30 kPa. Damage symptoms, mortality rate, leaf water content, photosynthetic, and biochemical parameters (amino acids, sugars, phenolics, and pigments) were determined. At the phenotypic level, based on damage symptoms and mortality, Q. ilex behaved as the most drought tolerant species. Drought caused a significant decrease in leaf fluorescence, photosynthesis rate, and stomatal conductance in all Quercus spp. analyzed, being less pronounced in Q. ilex. There were not differences between irrigated and non-irrigated Q. ilex seedlings in the content of sugar and photosynthetic pigments, while the total amino acid and phenolic content significantly increased under drought conditions. As a response to drought, living Q. ilex seedlings adjust stomata opening and gas exchange, and keep hydrated, photosynthetically active, and metabolically competent. At the population level, based on damage symptoms, mortality, and physiological parameters, the eastern Andalusian populations were more tolerant than the western ones. These observations inform the basis for the selection of resilient genotypes to be used in breeding and reforestation programs.

中文翻译：

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气候干燥条件下栎属幼苗对缺水耐受性的响应和差异。和安达卢西亚Q.冬青种群

在造林计划中选择有弹性的精英基因型时，必须分析栎属（Quercus spp。）的耐旱性差异，并在物种和个体种群水平上表征这些反应的特征。这项工作的主要目的是评估五个Quercus spp下对缺水的反应和耐受性的差异。和五个安达卢西亚Q. Ilex种间和种内水平的种群。通过在平均37°C温度，28 W m-2太阳辐照度和41％湿度下保持水分28天，对在珍珠岩中生长的6个月大幼苗进行干旱处理。使用珍珠岩作为基质能够建立严重的干旱压力，使水的利用率从73％（田间持水量）降低到28％（干燥度），对应于0和-30 kPa的基质势。确定了损害症状，死亡率，叶片含水量，光合作用和生化参数（氨基酸，糖，酚和色素）。在表型水平，基于损伤症状和死亡率，冬青树表现为最耐旱的物种。干旱导致所有栎属物种的叶片荧光，光合速率和气孔导度显着降低。分析，在Q. ilex中不那么明显。灌溉和不灌溉Q. ilex幼苗的糖和光合色素含量没有差异，而干旱条件下总氨基酸和酚含量显着增加。作为对干旱的回应，住在Q. ilex幼苗调节气孔的开放和气体交换，并保持水分，光合活性和代谢能力。在人口水平上，根据破坏症状，死亡率和生理参数，安达卢西亚东部的人口比西部的人口更宽容。这些观察为选择育种和再造林计划中使用的有弹性基因型奠定了基础。