The influence of a relict distribution on genetic structure and variation in the Mediterranean tree, Platanus orientalis

Environmental implications and evidence of natural products from dental calculi of a Neolithic-Chalcolithic community (central Italy)

In this contribution, we investigated the role of plants in the prehistoric community of Casale del Dolce (Anagni, FR, central Italy), through microparticles recovered from dental calculus. The finding of a great amount of pollen types, even in form of compact lumps, could indicate use of natural substances, such as honeybee products and/or conifer resins. This plant-microremain record also suggested environmental implications relative to the Neolithic and Chalcolithic period. Additionally, the stability of the tartar microenvironment had preserved starches and other microparticles, such as one epidermal trichome, a sporangium, and fragments of plant tissue, rarely detected in ancient dental calculus. The detection of secondary metabolites in the ancient matrix confirmed the familiarity of this community with plant resources. All these data supply various interesting food for thought and expand the knowledge about the potential of dental calculus in archaeological and archaeobotanical fields with a special focus on palaeoecology.

Urban allergy review: Allergic rhinitis and asthma with plane tree sensitization (Review)

Respiratory allergies represent a major public health issue in the modern world. Pollens are among the most significant causes of seasonal allergic rhinitis, with pollens of wind-pollinated trees representing an important cause. Members of the Platanaceae family (Platanus acerifolia, Platanus orientalis) are well-recognized sources of allergenic pollens worldwide, due to their high capacity of sensitization and widespread usage as ornamental urban trees. Air pollution, characteristic to all important urban conglomerates in the world and provoked by diesel exhaust gases, industrial and domestic fumes, and biogenic volatile organic compounds represents another major public health issue. Plane trees, along with other species of trees, are one of the main sources of volatile compounds. Recent studies have demonstrated a strong correlation between air pollution and respiratory allergies, with airway chemical compounds intensifying the capacity of sensitization to allergenic pollens. This study presents an overview of the known negative elements on public health of the Platanus family.

Population genetic variation characterization of the boreal tree Acer ginnala in Northern China

Genetic diversity and differentiation are revealed particularly through spatio-temporal environmental heterogeneity. Acer ginnala, as a deciduous shrub/small tree, is a foundation species in many terrestrial ecosystems of Northern China. Owing to its increased use as an economic resource, this species has been in the vulnerability. Therefore, the elucidations of the genetic differentiation and influence of environmental factors on A. ginnala are very critical for its management and future utilization strategies. In this study, high genetic diversity and differentiation occurred in A. ginnala, which might be resulted from its pollination mechanism and species characteristics. Compared with the species level, relatively low genetic diversity was detected at the population level that might be the cause for its vulnerability. There was no significant relationship between genetic and geographical distances, while a significant correlation existed between genetic and environmental distances. Among nineteen climate variables, Annual Mean Temperature (bio1), Mean Diurnal Range (bio2), Isothermality (bio3), Temperature Seasonality (bio4), Precipitation of Wettest Month (bio13), Precipitation Seasonality (bio15), and Precipitation of Warmest Quarter (bio18) could explain the substantial levels of genetic variation (> 40%) in this species. The A. ginnala populations were isolated into multi-subpopulations by the heterogeneous climate conditions, which subsequently promoted the genetic divergence. Climatic heterogeneity played an important role in the pattern of genetic differentiation and population distribution of A. ginnala across a relatively wide range in Northern China. These would provide some clues for the conservation and management of this vulnerable species.

Functional and Structural Leaf Plasticity Determine Photosynthetic Performances during Drought Stress and Recovery in Two Platanus orientalis Populations from Contrasting Habitats

In the context of climatic change, more severe and long-lasting droughts will modify the fitness of plants, with potentially worse consequences on the relict trees. We have investigated the leaf phenotypic (anatomical, physiological and biochemical) plasticity in well-watered, drought-stressed and re-watered plants of two populations of Platanus orientalis, an endangered species in the west of the Mediterranean area. The two populations originated in contrasting climate (drier and warmer, Italy (IT) population; more humid and colder, Bulgaria (BG) population). The IT control plants had thicker leaves, enabling them to maintain higher leaf water content in the dry environment, and more spongy parenchyma, which could improve water conductivity of these plants and may result in easier CO2 diffusion than in BG plants. Control BG plants were also characterized by higher photorespiration and leaf antioxidants compared to IT plants. BG plants responded to drought with greater leaf thickness shrinkage. Drought also caused substantial reduction in photosynthetic parameters of both IT and BG plants. After re-watering, photosynthesis did not fully recover in either of the two populations. However, IT leaves became thicker, while photorespiration in BG plants further increased, perhaps indicating sustained activation of defensive mechanisms. Overall, our hypothesis, that plants with a fragmented habitat (i.e., the IT population) lose phenotypic plasticity but acquire traits allowing better resistance to the climate where they became adapted, remains confirmed.