Activity and activation state of ribulose-1,5-bisphosphate carboxylase of spruce trees with varying degrees of damage relative to the occurrence of novel forest decline.

The aim was to determine whether a reduced carboxylation efficiency in needles of damaged spruce trees (Picea abies), is derived from a direct impairment of the ribulose-1,5-bisphosphate carboxylase (RuBP carboxylase) or there is an indirect inhibition of the RuBP carboxylase. In 1985, 1986 and 1987 measurements of RuBP carboxylase activity were carried out at three locations. Trees of different ages and degrees of damage were examined. RuBP carboxylase was assayed using both a rapid extraction method to determine the initial activity and an in vitro test after total activation to determine the total activity. The activation state was calculated as the ratio of initial activity to total act…