EFFECTS OF UV-B TREATMENT ON THE DISTRIBUTION OF WAX TUBES ON SCOTS PINE NEEDLES

A UV-B experiment was conducted during two growing seasons in 1994-199 5 in greenhouses in the University of Oulu, Finland. Biologically effe ctive UV doses were 0 kJm(-2)d(-1), 2.2-6.6 kJm(-2)d(-1) and 5.6-16.8 kJm(-2)d(-1). Grafted Scots pine clones from the Kola Peninsula and pi ne seedlings from Kittila and Inari were used. Wax tube distribution o n needles was studied under a SEM equipped with a phase-analysing syst em. Significant differences in wax tube coverage emerged between the p rovenances, but not between the treatments. Wax tube distribution rang ed from 54-66% of the surface of the Kola Peninsula needles to 47-50% of the Kittila and 27-36% of the Inari needles. (C)1998 Elsevier Scien ce Ltd.