1993 Volume 48 Issue 5 Pages 727-730
The chronic effects of 0.1ppm O3 on injury expression and growth in several herbaceous plant species were investigated. Two-week-old morning glory, radish and sunflower were exposed to 0.1ppm O3 for 2 weeks in artificially-lit growth cabinets. Visible symptoms such as white fleck were revealed on leaves in these plants within 1-2 days, and the withering of old leaves was accelerated by O3, especially in radish. Diffusive conductances of lower to middle leaves were more or less reduced by O3. Dry weight growth in these plants was suppressed by O3 after 2 weeks of exposure, especially in radish and sunflower. However, partitioning of dry matter was significantly affected by O3 as observed in the lower root weight ratio (RWR) in O3-exposed morning glory and radish. The possibility of good plant indicator systems for monitoring ambient atmosphere is also discussed.
