Open top chamber experiment "Edelmannshof": Carbohydrate and energy metabolism in needles and trunks from Norway spruce fumigated with unfiltered or charcoal-filtered air in comparison with untreated trees

1997

S. 133-164

4, Tab., 23 Abb., 30 Lit. Ang.

Unselbständiges Werk

200104678

As part of a five-year-lasting open-top-chamber experiment at the "Edelmannshof" site (Welzheimer Wald) we analyzed Norway spruce trees (Picea abies (L.) Karst.) with regard to carbohydrate and energy (ATP/ADP ratio) metabolism. End products, intermediates, and a regulator ofn carbon allocation (starch, sucrose, hexoses, fructose-2,6-bisphosphate) as well as enzyme activities involved in sucrose metabolism (sucrose-P synthase, sucrose synthase, acid invertase) were determined in needle and trunk samples of the different treatments (charcoal-filtered, unfiltered, ambient air). Changes of these parameters were documented annually and with regard to needle development (up to 2 years after bud break), and diurnally during a ozone period in midsummer. Samples from trees grown in an unfiltered atmosphere showed relatively high sucrose and hexose contents of the needles. The capacities of sucrose-P synthase (increased; sucrose synthesis) and acid invertase (decreased; sucrose cleavage) were affected in an opposite manner, indicating some preponderance of sucrose formation. While this difference was perpetuated during the vegetation period, episodically increased ratios of ATP/ADP coincided with increased ozone and SO2 concentrations. In addition, starch levels in needles treated with unfiltered air were decreased during an ozone period (July 1991). Taken together, these data indicate some short-time metbolic response with respect to transiently increased levels of, e.g., ozone, which could be taken as evidence for an increased glycolytic consumption of photoassimilates (ATP/ADP ratio increased; F26BP with a tendency to higher levels). These responses, however, appear to be reversible and only of limited nature with respect to the whole plants, as trunk parameters are not affected.