• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2005.11a
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• pp.367-370
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• 2005

The risk from genetically modified (GM) plants results from the possibility of gene contamination producing adverse effects on biological diversity by introducing herbicide or insect resistance into related plants or weeds (NAS 2002). The concern about the leakage of genes from GM plants into the environment has primarily focused on pollen that could be wind-borne for long distances. During the period of fisk assessment in Japan, physical containment is applied as a measure of reducing gene flow via the dispersal of pollen from GM plants into the surrounding environment In this study, we tried to estimate the effect of physically contained greenhouse covered by 1-mm fine mesh to reduce pollen dispersal by researching cross pollination rate between non-GM yellow maize in a greenhouse and silver maize outside the greenhouse.

• Journal of Ecology and Environment
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• v.34 no.4
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• pp.371-379
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• 2011

To determine the peak dispersal times of allergenic pollen grains in Ulsan, Korea, we performed continuous airborne pollen counts at three stations (Sts. A, B, and C) in Ulsan from August 2009 to November 2010. Pollen grains were sampled using a Durham sampler. Two peak pollen dispersal seasons were observed per year. The peak seasons generally coincided with the flowering period of anemophilous trees: Taxodiaceae (February), Alnus (March), Cupressaceae (April), Quercus, and Pinus (May), and with the flowering phase of herbs from August to November, e.g., Humulus, Artemisia, Gramineae, and Ambrosia from August through September. The highest concentration of airborne pollen was from Pinus (68%), followed by Quercus (15%), Alnus (6%), and Humulus (2%); whereas very low pollen concentrations were from Taxodiaceae, Cupressaceae, Artemisia, Gramineae, and Ambrosia (${\leq}$ 1% of the annual total airborne pollen concentration). Our findings indicate that Alnus and Humulus pollen are major allergens whereas those of Pinus and Quercus are minor allergens. The concentration of Alnus pollen grains at St. C was over five times that at Sts. A and B. This finding implies that individuals living at or near St. C are exposed to high concentrations of Alnus pollen before and after March, which is the flowering period of the alder tree. From August to September, individuals living at or near St. B are exposed to high concentrations of Humulus pollen. Our study suggests that Alnus pollen may be the major aeroallergen causing pollinosis in the spring at St. C and Humulus pollen may be the major aeroallergen in autumn at St. B.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.55 no.4
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• pp.365-370
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• 2010

The pollen dispersal by wind can make an important to understanding the viability and evolution of plants in ecological and agricultural science. Modelling can be applied to evaluate concerns about the spread of engineered pollens from genetically modified (GM) crops. Here, we are using gamma model to estimate the level of dispersal distance of pollen in the cross-pollination between two different maize (Zea mays L.) cultivars in GMO field of Korea University during the year 2010. The result of estimation of model indicates maximum pollen dispersal distance of estimated proportion of cross-pollination of maize was reached to 0.1% in 525 meter northwest due to the wind. We identify further measurements necessary to improve the accuracy of the model predictions.

• Journal of Plant Biotechnology
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• v.34 no.1
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• pp.47-53
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• 2007

To assess the risk of genetically modified (GM) rice on the agricultural ecosystem, agronomic characteristics, pollen longevity and outcrossing rate between GM (Iksan 483 and Milyang 204) and non-GM (their wild types and female parents) varieties were investigated using the bar gene as a tracer marker in paddy field. The agronomic characteristics of two GM rice were similar to their female-parents (non-GM rice) except heading date and 1,000 grain weight of Iksan 483, and they did not show a difference by the introgression of the bar gene as the genetic traits of rice varieties. Pollen viability was more than 90% just after shedding, and it was rapidly decreased below 50% at 5 minutes after shedding both GM and non-GM varieties. The Pollen longevity was lost after 30 minutes of anthesis. When the distance of gene flow from GM to non-GM rice detected to 6 m from the edge of GM rice plant, the maximum distance of pollen dispersal was 4.5m and 3.9m in Iksan 483 and Milyang 204, respectively, and that was increased in order of west, south, east, and north to the dominant wind direction, west-south. Mean outcrossing rate was very low as 0.003 and 0.001% within 1.5 m from the edge of Iksan 483 and Milyang 204, and the GM hybrids by the pollen dispersal did not detected over 4.5 m from the edge of GM rice plant. The results may help to establish the strategy which reduce the risk of pollen-mediated gene flow between GM and non-GM rice.

• Atmosphere
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• v.25 no.2
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• pp.221-233
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• 2015

Pollen is closely related to health issues such as allergenic rhinitis and asthma as well as intensifying atopic syndrome. Information on current and future spatio-temporal distribution of allergenic pollen is needed to address such issues. In this study, the Community Multiscale Air Quality Modeling (CMAQ) was utilized as a base modeling system to forecast pollen dispersal from oak trees. Pollen emission is one of the most important parts in the dispersal modeling system. Areal emission factor was determined from gridded areal fraction of oak trees, which was produced by the analysis of the tree type maps (1:5000) obtained from the Korea Forest Service. Daily total pollen production was estimated by a robust multiple regression model of weather conditions and pollen concentration. Hourly emission factor was determined from wind speed and friction velocity. Hourly pollen emission was then calculated by multiplying areal emission factor, daily total pollen production, and hourly emission factor. Forecast data from the KMA UM LDAPS (Korea Meteorological Administration Unified Model Local Data Assimilation and Prediction System) was utilized as input. For the verification of the model, daily observed pollen concentration from 12 sites in Korea during the pollen season of 2014. Although the model showed a tendency of over-estimation in terms of the seasonal and daily mean concentrations, overall concentration was similar to the observation. Comparison at the hourly output showed distinctive delay of the peak hours by the model at the 'Pocheon' site. It was speculated that the constant release of hourly number of pollen in the modeling framework caused the delay.

• Korean Journal of Plant Resources
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• v.28 no.1
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• pp.101-110
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• 2015

Parameters of mating system and pollen flow of a Pinus densiflora population in Buan, South Korea, were estimated using seven nuclear microsatellite markers. The expected heterozygosity ($H_e$) was 0.614 in mother trees and 0.624 in seeds. Fixation index (F) was 0.018 and 0.087 in each generation. There was no significant genetic difference between the generations (P > 0.05). From MLTR, the outcrossing rate ($t_m$), the biparental inbreeding ($t_m-t_s$), and the correlation of paternity ($r_p$) were 0.967, 0.057, and 0.012, respectively. tm was larger but $t_m-t_s$ and $r_p$ were smaller than those of allozyme markers in Pinus densiflora. These values were similar to those of microsatellite markers in other pine species. The optimal pollen dispersal model from TwoGener was the normal dispersal model with the effective density of 220 trees/ha and its level of genetic differentiation in pollen pool structure (${\Phi}_{ft}$) was 0.021. The average radial distance of pollen flow (${\delta}$) was calculated as 11.42 m, but no correlation between the pairwise-${\Phi}_{ft}$ and the geographical distance among mother trees was at Mantel test (r = -0.141, P > 0.05). Although the effective pollen dispersal in the population seems to be restricted, the amount of genetic variation might be maintained in each generation without a loss of genetic diversity. It might be because the genetic diversity in pollen pool was high but the genetic difference between pollen donors was small under the complete random mating condition in the Pinus densiflora population in Buan.

• Journal of Korean Society for Atmospheric Environment
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• v.29 no.6
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• pp.780-788
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• 2013

This study attempted to determine important meteorological parameters related to airborne pollen concentrations in urban areas. Hourly pollen measurement data were prepared from a regular sampling with a volumetric Burkard spore trap at a site in the Ulsan city, during the spring season (March~May) of 2011. Results showed that the daily mean and maximum concentrations for total pollen counts during the spring season were statistically significantly correlated with both air temperature and wind speed; daily mean pollen concentration was the most highly related to daily maximum temperature (r=0.567, p<0.001). It was also identified that pollen concentration has a stronger relationship with wind speed at the rural site than at the urban one, which confirms that strong wind conditions over the pollen sources area can be favorable for pollen dispersal, resulting in increases in airborne pollen concentrations downwind. From the results of an oak-pollen episode analysis, it was found that there was a significant relationship between hourly variation of oak pollen concentrations and dynamic meteorological factors, such as wind and mixing height (representing the boundary layer depth); especially, a strong southwestern wind and elevated mixing height was associated with high nocturnal concentrations of oak pollen. This study suggests that temperature, wind, and mixing height can be important considerations in explaining the pollen concentration variations. Additional examination of complex interactions of multiple meteorological parameters affecting pollen behavior should be carried out in order to better understand and predict the temporal and spatial pollen distribution in urban areas.

• Journal of Forest and Environmental Science
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• v.28 no.1
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• pp.1-7
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• 2012

Tropical forests whether fragmented or undisturbed or be they equatorial or deciduous, remain the storehouse of biodiversity for hundreds of thousands of plant and animal species. This unique characteristic continues to attract a wide range of scientists and international organizations to study and attempt to understand tropical forest ecosystems. Gene flow is mediated by pollen, seed and seedling dispersal, and factors affecting this gene flow include phenology, spatial distribution, population structures, seed predation, sexual and mating systems as well as physical and biological barriers to gene flow. Two methods are used in measuring gene flow: direct method that relies on the actual observation of seed and pollen dispersal, whereas indirect methods involve the use of genetic markers such as allozymes and DNA techniques. Political strife, extreme natural and artificial disasters, the lack of a comprehensive forestry research vision, coupled with difficult socio-economic conditions in Africa have made the environment quite difficult for sustained research activities on the part of those undertaking or wishing to undertake such studies. Gene flow studies in this region are few and far between. This review elaborates on the mechanisms of gene flow mediation in Sub-Saharan Africa.

• Asian Journal of Atmospheric Environment
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• v.7 no.4
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• pp.191-198
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• 2013

Cryptomeria japonica pollen is the most common pollen, which are scattering during each spring season in Japan. Japanese cedar (Cryptomeria japonica) pollinosis is one of seasonal allergic rhinitis that mainly occurs in Japan. In addition, long range transportation of Yellow Sand from the East Asian continent was also found during the pollen scattering seasons in Japan. Therefore, the interaction or impact between pollen and Yellow Sand should be concerned. In this study, our objective was to investigate the airborne behaviour of Cryptomeria japonica pollen grains and its size-segregated allergenic (Cry j 1) particles as the airborne tracer of Cryptomeria japonica pollen during the Yellow Sand events. Airborne Cryptomeria japonica pollen grains and its size-segregated allergenic particles were collected at roadside of urban residential zones of Saitama city during the pollination periods from February to March in two year investigation of 2009 and 2010. The overlap of Yellow Sand events and dispersal peak of pollen grains was observed. According to the Meteorological data, we found that the peaks of airborne pollen grains appeared under higher wind speed and temperature than the previous day. It was thought that Yellow Sand events and airborne pollen counts were related to wind speed. From the investigation of the airborne behavior of the size-segregated allergen particles by determining Cry j 1 with Surface Plasmon Resonance (SPR), the higher concentrations of the allergenic Cry j 1 were detected in particle size equal to or less than $1.1{\mu}m$($PM_{1.1}$) than other particle sizes during Yellow Sand events, especially in the rainy day. We conclude that rainwater trapping Yellow Sand is one of the important factors that affect the release of allergenic pollen species of Cry j 1. Therefore, it is very important to clarify the relationships between Cryptomeria japonica pollen allergenic species and chemical contents of the Yellow Sand particles in further studies.

• Animal cells and systems
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• v.5 no.2
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• pp.101-106
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• 2001

AFLPS (amplified fragment length polymorphisms) were used to estimate the genetic diversity of seven populations of Brassica campestis L. ssp. napus var. nippo-oleifera Makino between naturalized and cultivated populations. The seven Korean populations maintained a high level of genetic diversity. For example, all eight primers were high polymorphic, with an average of 3.2 effective alleles per primer set, and the expected heterozygosity was also high. The majority of genetic variance resided within populations The combinations of an insect-pollinated, outcrossing breeding system, large populations sizes, a high degree of gene flow and a propensity for high fecundity may explain the high level of genetic diversity within cultivated populations. Estimates of genetic similarity on the proportion of shared fragments ranged from 0.952 to 0.999. The high level of gene flow In Korean naturalized populations is mainly caused by seed dispersal via sea tide and the gene flow of cultivated populations may be enhanced in part by artificial pollen dispersal.