ANALYSIS OF ATMOSPHERIC POLLEN GRAINS IN DURSUNBEY ( BALIKESİR ) , TURKEY

In this study, airborne pollen grains in the atmosphere of Dursunbey (Balıkesir, Turkey) were collected using a gravimetric method. The pollen grains were investigated by light microscopy and a total of 6265 pollen grains per cm were counted. 42 different pollen types were identified of which 24 belonged to the arboreal plants (86.17% of the annual pollen index) and 18 to non-arboreal plants (13.16% of the annual pollen index). A small portion of the pollens (42 grains, 0.67%) were not identified. The most frequent pollen types, which constituted more than 1% of annual pollen count were regarded as the predominating pollen types for the region. The predominating group was determined to be consisted of pollens of Pinus L. (48.23%), Cupressaceae Rich. ex Bartl./Taxaceae Gray (16.74%), Poaceae Barnhart (8.32%), Quercus L.(5.31%), Acer L. (4.07%), Platanus L. (3.10%), Juglans L. (2.26%), Abies Mill. (1.75%), Plantago L. (1.25%), Amaranthaceae Juss. (1.22%) and Olea europaea L. (1.16%). The highest pollen count was determined in May and it is striking that most of the determined predominant pollen types have previously been reported as main causes of pollinosis.


Introduction
Pollen is the male gametophyte that plays an important role in pollination of flowering plants.The movements of pollens from one flower to the others can take place through different ways but wind and insects are the two vectors with the greatest share in pollination.Atmospheric occurences of pollens of wind pollinated plants are considered to be very important in terms of human health.Pollens found in the atmosphere may cause allergic symptoms in susceptible individuals like mucous membrane irritation, chronic bronchitis, allergic rhinitis and asthma, extrinsic allergic alveolitis (hypersensitivity pneumonitis), inhalation fever, humidifier fever or organic dust toxic syndrome, and immunological response impairment (Lacey & Dutkiewicz 1994).It has been reported that the ratio of individuals complaining from pollinosis in Europe reached up to 40% (D'Amato et al. 2007).The changing meteorological conditions and climate along with the increasing air pollution in urbanized areas increase the allergenicity of pollen grains in the atmosphere.For this reason, pollen calendars have been prepared in many countries (Giner et  This study was performed i) to determine airborne pollen types and their densities in the atmosphere of Dursunbey in Balıkesir province in Turkey, ii) to show seasonal variations of pollen types and iii) to prepare a pollen calendar for the sampling area.

Materials and Methods
The study area Dursunbey is located at 39° 34.8' N, 28° 37.8' E in northwest of Turkey at an altitude of 639 m above sea level.It covers an area in the eastern part of Balıkesir and geographically occupy a place in Marmara region of the country.The hilly characteristic of the study area is notable and most parts of the area is covered with Pinus nigra Arn.forests, making Dursunbey a famous region with its timber and a well-known exporter of it.The region has a Mediterranean climate type and the floristic structure shows transitional features between Euro-Siberian and Mediterranean phytogeographic regions.The major vegetation in the study area and its surroundings consists of Pinus nigra Arn.subsp.pallasiana (Lamb.)Holmboe, Abies nordmanniana (Stev.)

Palynological study
A Durham sampler was used as the gravimetric sampler which was operated from January to December 2012.The sampler was placed on the roof of a building at a height of 9 m above ground level.The slides of the sampler were covered with glycerine jelly mixed with basic fuchsin (Charpin & Surinyach 1974) before exposure and were changed weekly with new ones.Weekly slides were examined by light microscopy (Olympus BX51 trinocular light microscope) and the raw data was converted to pollen number in cm 2 .For pollen assignments, Uludağ University Palynology Laboratory reference collection was used.

Results
A total of 6265 pollen grains from 42 taxa were recorded in the atmosphere of Dursunbey annually.Most of the pollen grains (5399 grains of 24 taxa, 86.17%) were found to be arboreal, while 824 pollen grains of 18 taxa (13.16%) were non-arboreal.A small portion of the pollens (42 grains, 0.67%) were unidentified (Table 1).
Pollen types that comprised more than 1% of the annual total pollen number were considered to be dominant.Weekly variations of these dominated taxa are shown in Fig. 3 and pollen calendar that shows pollination seasons of all identified taxa are shown in Fig. 4.
The pollen season of Pinus started by the beginning of March (9 th week) and lasted in the 4 th week of September (38 th week).The highest level of Pinus pollens was recorded in the 4 th week of April (17 th week) with 558 pollen grains (Figs.3-4).Cupressaceae/Taxaceae pollens started to appear in the 1 st week of February (5 th week), the peak value was recorded in the 4 th week of April with 267 pollen grains and disappearance took place in the 3 rd week of October (42 nd week) (Figs.3-4).The relatively short pollen season of Quercus started in the 1 st week of April (14 th week) and lasted in the 3 rd week of June.The highest levels of oak pollen grains were recorded in the 2 nd week of May (19 th week) with 112 grains (Figs.3-4).Pollen grains of Acer were found as a predominating pollen type with an annual percentage of 4.07 (Table 1).The pollen season of Acer started in the 2 nd week of February (6 th week) and lasted in the 1 st week of June (22 nd week).The highest number of Acer pollen grains (117 pollen grains) were recorded in the 3 rd week of May (20 th week) (Figs.3-4).The pollen season of Platanus was very short and started in the 2 nd week of April and lasted in the 4 th week of May (21 st week).The highest pollen number of this genus (73 pollen grains) was recorded in the 4 th week of April (Figs.43-4).The pollen season of Juglans began in the 3 rd week of April (16 th week) and lasted by the beginning of June.The highest levels of Juglans pollens were observed in the 2 nd week of May with 66 pollen grains (Figs.3-4).
Juglans appeared to be one of the main pollen producers with an annual value of 2.26%.The pollen grains of Abies were sampled from the 3 rd week of April until the 3 rd week of August (33 rd week).Maximum pollen load of Abies was recorded in the last week of June (26 th week) with 32 pollen grains (Figs.3-4).The last dominating pollen type was of Olea europaea and showed a very short pollen season, which started in the 4 th week of May (2 st week) and lasted in the last week of June.The highest level of Olea europaea pollen grains (39 grains) was recorded in the 1 st week of June (Figs.3-4).
Poaceae was the most common herbaceous plant whose pollen grains started to be seen from the 2 nd week of April (15 th week) to the end of November (47 th week) with its highest value in the 3 rd week of June (24 th week) with 92 pollen grains (Figs.3-4).The pollen season of Plantago started in the 2 nd week of April and lasted at the end of August.The highest number of Plantago pollen grains was recorded in the 3 rd week of June with 16 pollen grains (Figs.3-4).The pollen season of the family Amaranthaceae was long and started by the beginning of June and lasted in the 1 st week of November (44 th week).The highest number of pollen grains (10 grains) was recorded in the 1 st week of September (35 th week) (Figs.3-4).

Discussion
Airborne pollen grains of arboreal plants were found to be predominant in the atmosphere of Dursunbey with a ratio of 86.17% most probably as a result of the geographical location, climate and vegetation of the study area.The same dominancy for arboreal pollen types have previously been reported in Balıkesir (70.92%) ( The pollen grains of pine was the most frequent pollen type during the investigation period due to widespread pine forests present at higher altitudes of the study area and its surroundings.Pine pollen has previously been recorded as a predominated pollen type with high percentages also in İzmir (57.30%) (Guvensen et  Quercus, one of the main allergenic pollen types (Spieksma 1990, D'Amato et al. 1991) was found as a predominated pollen type with the annual percentage of 5.31% in the atmosphere of our study area (Table 1).Quercus has previously been reported as the main pollen type from many regions in Turkey including Çanakkale (9.28%) (Guvensen et  In conclusion, the annual sampling of the airborne pollen grains in Dursunbey atmosphere showed presence pollens of 24 arboreal and 18 non-arboreal plants.A total number of 6265 pollen grains per cm 2 were counted during the sampling period and the main pollen producers were recorded as Pinus, Cupressaceae/Taxaceae, Poaceae, Quercus, Acer, Platanus, Juglans, Abies, Plantago, Amaranthaceae, and Olea in Dursunbey atmosphere.Most of the predominated pollen types have previously been reported as important allergenic pollen types.We hope the calendar designed by us will be helpful for medical treatment of patients complaining from pollen allergy in Dursunbey and its surroundings.

Fig. 2 .
Fig. 2. The annual percentages of main pollen types determined in the atmosphere of Dursunbey.

Fig. 3 .Fig. 4 .
Fig.3.Main pollen producers and their weekly variations in the atmosphere of Dursunbey.The letters in the X axis correspond to the sampling months.

Table 1 .
The annual pollen numbers and percentages of arboreal plants (AP) and non-arboreal plants (NAP) sampled in the atmosphere of Dursunbey.

Table 2 .
Monthly percentages of airborne pollen grains of arboreal plants (AP) and non-arboreal plants (NAP)in the atmosphere of Dursunbey.