© 2003 Heron Publishing—Victoria, Canada
Developmental lignification and seasonal variation in β-glucosidase and peroxidase activities in xylem of Scots pine, Norway
spruce and silver birch
Kaisa Marjamaa (1), Mikko Lehtonen (1), Taina Lundell (2), Merja Toikka (3), Pekka Saranpää (3) and Kurt V. Fagerstedt (1, 4)
1. Department of Biosciences, Viikki Biocenter, P.O. Box 56, FIN-00014 Helsinki University, Finland / 2. Department of Applied Chemistry and Microbiology, Viikki Biocenter, P.O. Box 56, FIN-00014 Helsinki University, Finland / 3. Laboratory of Organic Chemistry, Department of Chemistry, University of Helsinki, FIN-00014 Helsinki, Finland / 4. Author to whom correspondence should be addressed (kurt.fagerstedt@helsinki.fi) / Received May 31, 2002; accepted April 4, 2003; published online September 1, 2003
Summary
We examined the relationship between β-glucosidase and peroxidase activities and xylem lignification in the stems of Scots
pine (Pinus sylvestris L.), Norway spruce (Picea abies (L.) Karst.) and silver birch (Betula pendula Roth) during the 1999 growing season. Examination of stem cross sections stained with safranin and Alcian blue for lignin
and cellulose, respectively, indicated that radial growth of pine and spruce xylem began in late May, whereas the growth of
birch xylem was initiated 2 weeks later. Lignification began soon after thickening of the newly formed cell walls, i.e., upon
deposition of cellulose. Hydrolysis of the synthetic β-glucosidase substrate p-nitrophenyl-β-O-D-glucopyranoside was correlated with radial growth and lignification in the xylem of both conifers, but the relationship between
lignification and the hydrolysis of coniferin by β-glucosidase was not obvious. β-Glucosidase activities in the xylem of silver
birch were low and did not correlate with growth or lignification with either substrate. An increase in peroxidase activity
was detected at the initiation of growth and lignification in the conifers and during growth and lignification in silver birch,
but high peroxidase activities were also measured outside the growth period during late autumn, winter and early spring.
Keywords:
Betula pendula, lignin biosynthesis, Picea abies, Pinus sylvestris, plant peroxidase.
