Abstract
Object: Gramineae pollinosis has occurred frequently over the last 10 years. It is an urgent necessity for our allergy clinic to determine the source of airborne antigenic pollens. For an analysis of the Gramineae pollen, regular pollen observation has been performed using Durham's pollen trap since 1987 in Hisai, Mie, Japan; and the pollen count data showed an annual distribution pattern with two or three peaks, each in spring, summer and autumn. This study aimed to identify the Gramineae pollen source of the summer peak. Method: For airborne pollens, the major and minor axis of pollen grains were measured. Then, these measurements were compared with those of the pollen sample from the rice variety "Koshihikari", that is predominantly cultivated in the Hisai area. The comparison was made with the confidence ellipse of the two-variables analysis. Results: Most airborne pollens of the summer peak were almost round in shape and about 45 micron in the major axis, and at least 80% of them were within a 95% confidence ellipse given by the "Koshihikari" pollen. During the past 17 years, the heading date of "Koshihikari" varied from 17 July to 31 July, while the pollen season appeared in less than 7 days before or after the heading date. Furthermore, there was a statistically significant positive correlation between the rice yield/10a and the total count of airborne pollens during July and August. Conclusion: These results suggest that a considerably large number of airborne Gramineae pollens in mid summer originate from rice (Oryza saliva L.) in the middle area of Mie prefecture.
