Muller Clare T, Cera Andreu, Palacio Sara, Moore Michael J, Tejero Pablo, Mota Juan F, Drenovsky Rebecca E
Biology Department, John Carroll University, University Heights, OH, USA.
UMR 950 EVA, INRAE, Université de Caen-Normandie, Caen, France.
Ann Bot. 2024 Dec 31;134(6):1003-1012. doi: 10.1093/aob/mcae127.
Soil endemics have long fascinated botanists owing to the insights they can provide about plant ecology and evolution. Often, these species have unique foliar nutrient composition patterns that reflect potential physiological adaptations to these harsh soil types. However, understanding global nutritional patterns to unique soil types can be complicated by the influence of recent and ancient evolutionary events. Our goal was to understand whether plant specialization to unique soils is a stronger determinant of nutrient composition of plants than climate or evolutionary constraints.
We worked on gypsum soils. We analysed whole-plant nutrient composition (leaves, stems, coarse roots and fine roots) of 36 native species of gypsophilous lineages from the Chihuahuan Desert (North America) and the Iberian Peninsula (Europe) regions, including widely distributed gypsum endemics, as specialists, and narrowly distributed endemics and non-endemics, as non-specialists. We evaluated the impact of evolutionary events and soil composition on the whole-plant composition, comparing the three categories of gypsum plants.
Our findings reveal nutritional convergence of widely distributed gypsum endemics. These taxa displayed higher foliar sulphur and higher whole-plant magnesium than their non-endemic relatives, irrespective of geographical location or phylogenetic history. Sulphur and magnesium concentrations were mainly explained by non-phylogenetic variation among species related to gypsum specialization. Other nutrient concentrations were determined by more ancient evolutionary events. For example, Caryophyllales usually displayed high foliar calcium, whereas Poaceae did not. In contrast, plant concentrations of phosphorus were mainly explained by species-specific physiology not related to gypsum specialization or evolutionary constraints.
Plant specialization to a unique soil can strongly influence plant nutritional strategies, as we described for gypsophilous lineages. Taking a whole-plant perspective (all organs) within a phylogenetic framework has enabled us to gain a better understanding of plant adaptation to unique soils when studying taxa from distinct regions.
土壤特有植物长期以来一直吸引着植物学家，因为它们能为植物生态学和进化提供见解。通常，这些物种具有独特的叶片营养成分模式，反映了对这些恶劣土壤类型的潜在生理适应性。然而，由于近期和古代进化事件的影响，了解全球对独特土壤类型的营养模式可能会变得复杂。我们的目标是了解植物对独特土壤的特化是否比气候或进化限制更能决定植物的营养成分。
我们研究石膏土壤。我们分析了来自北美奇瓦瓦沙漠和欧洲伊比利亚半岛地区的36种石膏嗜性谱系本地物种的全株营养成分（叶、茎、粗根和细根），包括广泛分布的石膏特有植物（作为特化物种）以及分布狭窄的特有植物和非特有植物（作为非特化物种）。我们评估了进化事件和土壤成分对全株成分的影响，比较了三类石膏植物。
我们的研究结果揭示了广泛分布的石膏特有植物的营养趋同现象。无论地理位置或系统发育历史如何，这些分类群的叶片硫含量和全株镁含量均高于其非特有近缘种。硫和镁的浓度主要由与石膏特化相关的物种间非系统发育变异解释。其他营养元素浓度则由更古老的进化事件决定。例如，石竹目通常叶片钙含量高，而禾本科则不然。相比之下，植物磷的浓度主要由与石膏特化或进化限制无关的物种特异性生理决定。
正如我们对石膏嗜性谱系所描述的那样，植物对独特土壤的特化会强烈影响植物的营养策略。在系统发育框架内从全株角度（所有器官）进行研究，使我们在研究不同地区的分类群时能够更好地理解植物对独特土壤的适应性。
