Some Effects of Exposure to Sulphur Dioxide on the Metabolism of Scots pine in Winter : II. Effects on the Photosynthetic Carbon Metabolism

1986

S. 237-246

2 Abb., 28 Lit. Ang.

Unselbständiges Werk

200052380

The effect of sulphur dioxide was examined on the uptake of 14CO2 and the distribution of 14C among photoassimilates during the winter depression of activity and emergence from it in SO2-tolerant, SO2-relatively tolerant and SO2-susceptible clones of Scots pine (Pinus sylvestris L.). Detached twigs were treated with 1.0 ppm SO2, 6h daily over 3 consecutive days. The fumigated twigs were then exposed to 14CO2 for 5 min. Low winter temperatures and exposure to SO2 inhibited the subsequent total 14CO2 uptake, decreased the percentage of label in starch, glycolate, glycine and serine. On the other hand there was a marked increase in the percentage of label in sucrose, aspartate, glutamate, alanine and malate. The degree of inhibition or stimulation varied with the susceptibility of trees to SO2 and was greatest in the most susceptible one.