Some Effects of Exposure to Sulphur Dioxide on the Metabolism of Scots Pine in the Winter : I. Effects on Photosynthesis and Respiration

1986

S. 229-236

2 Abb., 16 Lit. Ang.

Unselbständiges Werk

200052369

The rates of carbon dioxide exchange were studied during winter depression and emergence from it in shoots of three Scots pine clones, a SO2-tolerant one, a SO2-relatively tolerant one and a SO2-susceptible one, following exposure to 1.0 ppm SO2 for 1, 2, or 3 days 6h a day. The CO2 exchange rates were measured using a infra-red CO2 analyser. The rates of photosynthesis (PN) and photorespiration (RL) were inhibited by SO2 much more in the susceptible clone than in the tolerant one over a 55h period following transfer from natural winter (January) conditions into the laboratory. On the other hand dark respiration rate (RD) was either stimulated or inhibited by SO2 depending on the duration of warm conditions and fumigation with SO2.