Ecology and pollen database of shrub and cultivated herbaceous plant species in Tehran: An ecological management and urban safety approach

Field: Environmental Science (Physical Sciences)

Introduction: Palynology as a multidisciplinary science can provide data base for a wide range of sciences such as Plant Systematics, Melissopalynology (quality control of honey), Aeropalynology, Stratigraphy, Palynology, Forensic Palynology, Paleoclimate, prediction and simulation of past climatic events, Archaeology, phylogeny, etc. Because several cultivated and ornamental species are classified as allergenic plants, identification, classification, and preparation of their database have particular importance. So far, few studies has been carried out on palynology in Iran. Therefore, it seems that carrying out a palynological study and preparing its database in Tehran is the first step in allergy research. The objectives of this study were to investigate the morphological and micro-morphological characteristics and classification, as well as preparing palynological database in Tehran.Material and methods: Tehran has an area of about 600 km2 due to its location on the southern slopes of the Alborz Mountainous Region, widely extended along north to south and east to west zones, therefore showing a variety of climatic conditions that include diverse species (e.g., ornamental, etc.). So, after reviewing the published flora and present information on green space databases in the area, target taxa were selected. The plant samples were collected by field samplings and were deposited based on standard methods. Finally, the pollen grains were coated with gold material. Then, they were scanned with Scanning Electron Microscopy (SEM). Afterward, they were identified by diverse pollen references on palynology.Results and discussion: The results of this study include the preparation of a native visual source about the pollen grains of 145 species of shrubs and cultivated herbaceous plant species in Tehran. These 145 plant species belong to 65 families, including 95 herbaceous species and 50 shrub species. Asteraceae (16 species) and Rosaceae (14 species) had the most species. Among the 131 studied genera, 43 genera were reported to be allergic. Asteraceae with 5 genera and Cupressaceae and Oleaceae with 3 genera had the highest frequency of allergenic species among the studied families. The results of this study showed that allergenic shrubs are more abundant than allergenic herbaceous plants. However, trees and shrubs have more allergenic effects due to more pollen production and wind pollination. The pollen grains of these species are usually small and can be scattered over long distances and have a longer durability in the air. The results of this study show that allergic pollens also have a high morphological diversity, however, the significant effect of pollen grain micro-morphological characteristics on allergies requires more extensive studies.Conclusion: The achievements of this study will serve as a pilot for the study of palynological study, especially in asthma and allergy in the country. The results of this study show that in Tehran, several plant species have been planted without considering allergenic considerations, which should be considered as an important warning for ecological managers of the city.