Majid Beheshti; Ahmadreza Mehrabian; Farzaneh Khajoei Nasab; Mohammad Reza Fazlollahi
Abstract
Tehran is one of the metropolises of Asia as well the world that needs careful ecological assessments as well management planning. Providing a pollen database is one of the important measures in order to manage the environment of this city. This database is the primary step of the Pollen Atlas of Iran ...
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Tehran is one of the metropolises of Asia as well the world that needs careful ecological assessments as well management planning. Providing a pollen database is one of the important measures in order to manage the environment of this city. This database is the primary step of the Pollen Atlas of Iran as well pollen calendar, the management of asthma and allergies, as well as archaeological studies in Tehran. Up to now little attention paid to this scope, so it seems to be necessary to preparation the mentioned data base. Plant samples of this study were collected from parks and various urban green spaces of Tehran. As well deposited in the herbarium of Shahid Beheshti University (HSBU). These specimens were identified using scientific sources as well valid flora such as Flora of Iran, Flora Iranica and etc. The pollen grains were photographed using Scanning Electron Microscopy (SEM). The 12-20 pollen grains were evaluated using Image Tools 3.6 software to evaluate quantitative morphological traits. Finally, a comprehensive description of the quantitative and qualitative morphological traits of pollen grains was prepared. In this study, pollen grains of 92 species belonging to 42 trees and herbaceous plant genera were studied. The Asteraceae with 11 species has the highest number of species in this study. The pollen grains including monad (91) tetrad (1). Also 70 species are isopolar and 22 species are heteropolar. Sculpturing including 16 different types. This study is the first illustrated pollen data base on Tehran that is an important reference to history of agriculture and archeology in the region. The data of this study showing several species in Tehran have been planted regardless of their allergic effects, so, it should be considered in the expansion of green space.
Tayebeh Akbari; Raziyeh Lak; Reza Shahbazi; Kamallodin Alizadeh; Ashraf Asadi; Mehrnoosh Ghadimi
Volume 13, Issue 3 , October 2015, , Pages 89-102
Abstract
Abstract: In this research we tried to investigate the respond of high part of Zagros Mountains to past climate change by studying a 300cm core was extracted from Lake Gahar. This region is as an important biome of oak forest of Iran. Then the aim of this investigation is to detect past climate condition ...
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Abstract: In this research we tried to investigate the respond of high part of Zagros Mountains to past climate change by studying a 300cm core was extracted from Lake Gahar. This region is as an important biome of oak forest of Iran. Then the aim of this investigation is to detect past climate condition by palynology and modeling. According to the pollen percentage diagram of Lake Gahar (Fig. 3, 4, 5), four main local pollen assemblage zones consisting of two older zones GHA(depth of 300 to 210 cm), GHB (210 to 65 cm depth) and two more new zones GHC (depth 65 to 30 cm) and GHD (depth 30 to 0 cm) were identified. For interpretation the pollen diagram we reconstructed the annual mean precipitation and temperature data over 40000 years by MCM (Macrophysical Climate Model). By calculation the Z-score index four major thermal and moisture period found in Gahar region: 1- Cold and dry period (40000-30000 Yr. B.P) 2- Warm and dry period (30000-20000Yr. B.P) 3- Cold and wet period (20000-11900 Yr. B.P) and 4- Warm and dry period (11900-now Yr. B.P). The indices and our data showed that two zones GHA and GHB beyond depth 300-60cm may have been exposed to cold and wet period around 20000-11900 Years B.P..The mentioned zones have vegetation of forest- steppe with dominant species of oak trees. It seems that the disappearing of arboreal pollen, especially Quercus at a depth of 50 and 60 cm at the boundary between the two zones GHB and GHC is associated with unfavorable conditions for plant growth during the last glacial period. There are also upland herbs pollen types such as Poaceae crealia types and polygonium, and also arboreal pollen such as Corylus, Juglans, olive and Vitis can be considered as evidence of the destruction of the region as a result of anthropogenic effects and heavy grazing and farming operations. It is approved that consecutive period of cold/wet and warm/dry period in the past climate of Gahar region by comparing the results with other lakes in the north west of Iran.
