1993 Volume 48 Issue 5 Pages 723-726
The impact of ozone (O3) on the growth of several woody plants was investigated. Potted juvenile plants were exposed to 0.1ppm O3 continuously for 3-4 weeks in artificially-lit growth cabinets. O3 induced some visible symptoms and defoliation in many broadleaf trees, whereas no visible damage was observed with Japanese red cedar and momi fir. Shoot elongation growth of Japanese red cedar and China laurestine was suppressed remarkably by O3, while growth of some broadleaf trees was accelerated in spite of defoliation. Thermal image analysis suggested that O3 induced stomatal closure in some woody plants after 3 weeks of exposure. O3 should be considered one causal factor of the “forest decline” observed throughout the world.