1. INTRODUCTION
The plant leaf surface, termed phyllosphere, supports the growth of a diverse microbiota of bacteria and fungi through the utilization of the resources available in this habitat (1; 2; 3; 4; 5). Therefore, phlloplanemicrootganisms occupy prominent positions in plant canopies. Among of this epiphytic phyllosphere community, yeasts are found in a wide variety of trees in temperate and tropical regions (6; 7; 8). They exist both as small colonies and single cells concentrated on the junctions between epidermal cells of leaves. The colonies increase in size by budding, as do true yeasts , but also actively discharge spores, mainly at night (6). Since the leaves of higher plants have evolved as gas-exchange organs ,in their relatively exposed position may act as effective pollutant traps. Leafyeasts are, therefore, in a very exposed position concerning to the physicochemical effects of gaseous and particulate pollutants of the air such as ozone, heavy metal and sulphur dioxide (9; 10; 11). Dowding and Carvill (12) were the first to report the negative influence of urban atmospheres on Sporobolomyces spp. Inhabiting leaves of ash plants growing in a series of urban areas of lreland. Further studies revealed that fungi and leafyeast populations were particularly sensitive to air pollutants, mainly sulphur dioxide (6; 7; 13; 14). Nakase et al. (8; 15) in the course of a survey of yeasts in the phyllosphere from plants in Taiwan, Found yeast strains belonging to the genus Sporobolomyces. However, no reports have been published on pattern of air quality revealed by the impact of pollution over leafyeast populations or another related to the counting of yeasts from the phyllosphere of trees, in Brazil. Our purpose was isolate ballistosporous yeasts from the phyllosphere of Bauhinia forficate (pata de vaca), Tabebuia sp. (ipe), and Terminalia catappa (chapeu de sol), wide-spread tree species in urban environments of Brazil. Two cities from Sao Paulo State (southeast of Brazil) were chosen to be sampled in winter and summer seasons of 2005/2006, one representing high pollution level from industrial activity (Cbatao) and the other, represented high quality of the air (Aguas de Sao Pedro).
1. บทนำThe plant leaf surface, termed phyllosphere, supports the growth of a diverse microbiota of bacteria and fungi through the utilization of the resources available in this habitat (1; 2; 3; 4; 5). Therefore, phlloplanemicrootganisms occupy prominent positions in plant canopies. Among of this epiphytic phyllosphere community, yeasts are found in a wide variety of trees in temperate and tropical regions (6; 7; 8). They exist both as small colonies and single cells concentrated on the junctions between epidermal cells of leaves. The colonies increase in size by budding, as do true yeasts , but also actively discharge spores, mainly at night (6). Since the leaves of higher plants have evolved as gas-exchange organs ,in their relatively exposed position may act as effective pollutant traps. Leafyeasts are, therefore, in a very exposed position concerning to the physicochemical effects of gaseous and particulate pollutants of the air such as ozone, heavy metal and sulphur dioxide (9; 10; 11). Dowding and Carvill (12) were the first to report the negative influence of urban atmospheres on Sporobolomyces spp. Inhabiting leaves of ash plants growing in a series of urban areas of lreland. Further studies revealed that fungi and leafyeast populations were particularly sensitive to air pollutants, mainly sulphur dioxide (6; 7; 13; 14). Nakase et al. (8; 15) in the course of a survey of yeasts in the phyllosphere from plants in Taiwan, Found yeast strains belonging to the genus Sporobolomyces. However, no reports have been published on pattern of air quality revealed by the impact of pollution over leafyeast populations or another related to the counting of yeasts from the phyllosphere of trees, in Brazil. Our purpose was isolate ballistosporous yeasts from the phyllosphere of Bauhinia forficate (pata de vaca), Tabebuia sp. (ipe), and Terminalia catappa (chapeu de sol), wide-spread tree species in urban environments of Brazil. Two cities from Sao Paulo State (southeast of Brazil) were chosen to be sampled in winter and summer seasons of 2005/2006, one representing high pollution level from industrial activity (Cbatao) and the other, represented high quality of the air (Aguas de Sao Pedro).
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