1993 Volume 28 Issue 5 Pages 279-287
The effects of simulated acid rain alone, or in combination with O3 on the dry weight growth of Japanese cedar seedlings (Cryptomeria japonica D. Don) were investigated. Two-year-old seedlings were exposed to simulated acid rain at pH 2.5, 3.5, 4.5 or 7.0 (120 ml/pot/day, 2 days/week) with two or three levels of O3 (charcoal filtered air containing O3 at 0.1 ppm, 0.2 ppm or 0.3 ppm, 4 hours/day, 3 days/week) for 12 weeks in open-top chambers.
There were no harmful effects of simulated acid rain and/or O3 on the dry weight growth of the seedlings. The seedlings treated with simulated acid rain at pH 2.5, or with 0.3 ppm O3 showed the increase in the partitioning of assimilates to foliage and the decrease in that to root during the experimental period. The chlorophyll content of foliage in the seedlings exposed to 0.3 ppm O3 reduced, and its color changed from green to yellowish green.
The results of these experiments suggest that high acidity of rain or high concentrations of O3 may induce changes in the partitioning of assimilates to plant organs and the reduction of chlorophyll content of foliage in Japanese cedar seedlings.
