Taira H, Teranishi H, Kenda Y
Forest Experiments Station, Toyama Forest and Forest Product Research Center.
Arerugi. 1992 Oct;41(10):1466-71.
We investigated the preseasonal blooming conditions of the male flowers of Sugi (Cryptomeria japonica D. Don) which flowers commonly in spring. We also investigated atmospheric Sugi pollen during all seasons for three years from 1988 through 1991 to determine pollen scattering in autumn. Our results showed that a discernible amount of pollen is scattered from the middle of October into December; this scattering would be expected in the following spring. Almost none of the buds of the flowers collected in October and in November bloomed when incubated at temperatures ranging from 6 degrees C to 20 degrees C after low-temperature treatment to arise the blooms from dormancy. However, small numbers of the male flowers from various Sugi trees bloomed and scattered pollen under these conditions. We found that the ratio of the blooming male flowers was one-third or less per blossom. The ratio changed depending on the growth stage and incubation conditions. In conclusion, the density of airborne Sugi pollen scattering is not high in autumn in general. However, the density would be expected to be high enough to induce allergic reactions and clinical symptoms in some areas of Sugi growth, especially in a good harvest year.
我们研究了通常在春季开花的日本柳杉雄花的季前开花条件。我们还在1988年至1991年的三年间对所有季节的大气中日本柳杉花粉进行了调查，以确定秋季的花粉散落情况。我们的结果表明，从10月中旬到12月会有可观数量的花粉散落；预计这些花粉会在次年春天出现。10月和11月采集的花的芽在经过低温处理以打破休眠后，在6摄氏度至20摄氏度的温度下培养时，几乎没有开花的。然而，在这些条件下，不同日本柳杉树上的少量雄花会开花并散落花粉。我们发现，每朵花中开花雄花的比例为三分之一或更低。该比例因生长阶段和培养条件而异。总之，一般来说秋季空气中日本柳杉花粉散落的密度不高。然而，预计在日本柳杉生长的一些地区，该密度足以引发过敏反应和临床症状，尤其是在丰收年份。
