Enzyme activites implied in carbon paritioning in spruce needles under different environmental conditions (Edelmannshof OTC experiment)

1997

S. 165-174

6 Abb., 7 Lit. Ang.

Unselbständiges Werk

200104679

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. Four trees outside at the same location were also included. The biochemical studies were made on current- and one- to four- years old needles harvested from February 1990 to March 1992. 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 (Gas3PDH) and the mitochondrial enzymes NAD-malic enzyme (NAD ME) and Fumarase (FUM). The main enzymatic changes in Edelmannshof occurred essentially in spring (before and during bud break) and in autumn. During spring, the PFP specific activity in the new leaves of all trees is up to 3 or 4 times higher than in one year-old needles. As concerns the treatment effect, the comparison between the trees in filtered and non filtered conditios showed no real differences due to the pollution effect. The results in Edelmannshof were hindered by a chamber effect depending on the enzyme and the harvest time. Moreover the individual differences between the four trees bearing the same treatment were very important. We have to conclude that in this experiment the great individual variability and the chamber effect mask any pollution effect that may exist.