SEASONAL COURSE OF CATALASE ACTIVITY AND CHLOROPHYLL CONTENT IN NEEDLES FROM NORWAY SPRUCE TREES OF DIVERSE GEOGRAPHICAL ORIGIN AT 2 DIFFERENT SITES

In the years 1989 and 1990 the seasonal course of the catalase activit y and chlorophyll content were measured in the needles of three Norway spruce trees (Picea abies [L.] KARST.) of different geographical orig ine. Two of these spruces, which are phenotypically and hence probably genetically different, were 25 years old at the time of the investiga tion: experimental tree Nr. 1 (provenance: Roumanian Carpathians, fast growing, late flushing) and Nr. 2 (provenance: northern Sweden, slow growing, early flushing). They stay in the experimental garden of the Institute of silviculture of the University Freiburg in a valley (420 m above sea level) at the same site, not far from each other. Experime ntal tree Nr. 3, 40 years old at the time of the investigation, is loc ated in the region of the summit of Schauinsland Mountain (1230 m abov e sea level) in the Black Forest. The main goal of this investigation was to test whether an endogenous, genetically determined control of t he catalase activity and chlorophyll content in the needles of trees c ould be demonstrated along with the known exogenous control by light. The following results were obtained: -In comparison to the fast growin g tree Nr. 1, the values of the catalase activity and chlorophyll cont ent based on the needle fresh weight were lower in the low growing tre e Nr. 2 from northern Sweden. - Both parameters showed a pronounced se asonal variation with lower values in the first half of the year and a rapid rise in the second half of the vegetation period. For experimen tal trees Nr. 1 and 3, catalase activity culminated in October, while for tree Nr. 2, this occurred already in September. This was observed not only for the needles of the current year, but also for the 1- and 2-years old needles. - The dry matter content of the needles per unit fresh weight was substantially higher for the tree Nr. 2 from northern Sweden than for the other 2 trees. - The catalase activity and chloro phyll content in the needles of all 3 experimental trees behaved essen tially similarly. They rose with increasing age and shading of the nee dles. These results are discussed, and in agreement with what is known from other investigations, it can be concluded that (1) the seasonall y shifted course of catalase activity in autumn can be inferred to be due to endogenous control. This control could be interpreted as the re sult of an adaptation to the different lengths of the photo- and veget ation periods, (2) with respect to the function of catalase in the cel l, the level of catalase activity possibly corresponds to the intensit y of photosynthesis,and (3) there are indications of a correlation bet ween catalase activity and chlorophyll content.