Abstract
The cultures of bryophyte spores were investigated as a bioassay to evaluate the effects of air pollutants in rain water.
The spores were sown on an agar culture medium added with rain water or distilled water (control), and then cultured at 25±2°C with a 12 hours light period (1, 050-1, 300 lux.). The rate of the spore germination and the protonemal growth were compared with those of the control 10 days after sowing.
The results were as follows:
1) The spore germination and protonemal growth were scarcely inhibited on the medium at the range of pH 5-8, but markedly inhibited below pH 5.
2) Heavy metal ions in rain water such as Cu2+, Zn2+ and Mn2+ had synergistic or additive inhibition on the spore germination and protonemal growth in combination with sea salt (NaCl).
3) The bioassay using rain waters collected by means of deposit gauge for a month showed that the germination and germ tube elongation of the spores cultured with rain waters at the industrial areas were inhibited in comparison with the control.
From the above results, it can be demonstrated that the bioassay of germination and protonemal growth of the spores of epiphytic bryophytes on the agar culture medium is a sensitive indicator for evaluating air pollutants in rain water.
