Enzyme Activities Implied in Carbon Partitioning in Spruce Needles under Different Environmental Conditions (Edelmannshof OTC Experiment) : 8. Statuskolloquium

1992

S. 179-188

7 Lit. Ang.

Unselbständiges Werk

200081348

The experiments were conducted in Edelmannshof (Black Forest) on 20-25 years old spruce (Picea abies (L.) Karst.) fumigated in open-top chambers with either untreated or charcoal-filtered ambient air. Two trees outside at the same location were also included. The biochemical studies were made on current- and one-year- old needles harvested from Frebruary 1990 to October 1991. The enzymes implicated in the use of photosynthates were extracted. They comprised glucose 6 phosphate dehydrogenase (G6PDH), ATP- and PPi- dependant phosphofructokinases (PFK and PFP) and fructose 1,6 bisphosphatase (F1,6BPase) participating to the starch-sucrose interconversion, the glycolytic enzyme NAD-glyceraldehyde 3 phosphate dehydrogenase (Gal3PDH) and the mitochondrial enzymes NAD-malic enzyme (NAD-ME) and fumarase (FUM). The main result in Edelmannshof is a clear chamber effect depending on the enzyme and the harvest time. Moreover the individual differences between both trees of the same treatment were very important. Nevertheless, during spring, the PFP specific activity in the young leaves is up to 3 or 4 times higher than in one-year-old needles. However, 3 months later, the levels were similar whatever the needle age. The comparison between the filtered and non filtered treatments showed no real differences due to the pollution effect. We have to conclude that the great individual variability and the chamber effect mask any pollution effect that may exist.