1-AMINOCYCLOPROPANE-1-CARBOXYLIC ACID, ITS MALONYL CONJUGATE AND 1-AMINOCYCLOPROPANE-1-CARBOXYLATE SYNTHASE ACTIVITY IN NEEDLES OF DAMAGED AND UNDAMAGED NORWAY SPRUCE TREES

Levels of free 1-aminocyclopropane-1-carboxylic acid (ACC), its malonyl conjugate (MACC) and ACC-synthase activity were significantly higher in the needles of damaged Norway spruce trees (Picea abies (L.) Karst) compared with those in undamaged trees during both the diurnal and seasonal courses. The concentrations of ACC and MACC, and ACC-synthase activity fluctuated much more intensively in the needles of damaged trees both in the diurnal and the seasonal courses than in those of undamaged ones, which implies that damaged trees respond more sensitively to the environmental conditions. ACC concentrations were the highest in summer and lowest in fall, while MACC concentrations seemed to increase during the year. The concentrations of ACC and MACC during the diurnal course present the relation of a power function. The results of the measurements on needles of different ages showed that the older the needles were, the more active the ACC-synthase was, and thereby more ACC and MACC were produced in the damaged trees.