The influence of urban environment on pollen grains of the silver birch (Betula pendula Roth) in conditions of Yakutsk

This paper studies variability of pollen grains of the silver birch in relation to the quality of urban environment. The material was collected in 12 sites. A total of 1,190 leaves and 24,000 pollen grains were examined and measured. The pollen fertility varied within 69–92%. Statistically significant decrease in fertility was observed in conditions of high-intensity traffic load, in the central area of the city, and where the road surface was in poor condition. Under the same conditions a statistically significant increase in percentage of «relatively fertile» pollen grains is observed. We found significant correlation between the level of fluctuating asymmetry (FA) and the share of fertile and half-fertile pollen grains. For fertility Spearman’s rho was –0,71; and for half-fertility, r = 0,66, p < 0,05. A similarly significant correlation (r = –0,7, p < 0,05) was found between the diameter of pollen grains and traffic load, which indicates a consistent organism response to environment deterioration. From the above, it follows that for assessment of environmental condition such characteristics of pollen grains as fertility, half-fertility, and pollen grain size can be used.