© 1993 Heron Publishing—Victoria, Canada
Influence of (22S,23S)-homobrassinolide on rooting capacity and survival of adult Norway spruce cuttings
H. Rönsch (1, 2), G. Adam (1), J. Matschke (3) and G. Schachler (3)
1. Institute for Plant Biochemistry Halle, POB 250, 0-4010 Halle/S., Germany / 2. Author to whom correspondence should be addressed / 3. Federal Research Centre for Forestry and Forest Products Hamburg, Institute for Forest Tree Breeding, 0-1277 Waldsieversdorf,
Germany / Received July 18, 1991
Summary
To determine whether brassinosteroids promote clonal propagation of mature coniferous trees, cuttings of adult Norway spruce
(Picea abies (L.) Karst.) trees were harvested in late March, treated with (22S,23S)-28-homobrassinolide (SSHB), and stored at 2 °C in
darkness until they were planted in May. Treatment of the cuttings with SSHB significantly enhanced the formation of adventitious
roots by increasing percent rooting from 50% in the control cuttings to 92% in the 60 ppm SSHB treatment. N6-Benzyladenine (BA) stimulated rooting slightly although not significantly, but it counteracted the stimulative effect of
SSHB when cuttings were treated with both compounds together.
In a second study, the above-ground parts of medium-sized mature clonal Norway spruce trees were pretreated from the end of
June till August with SSHB or BA or both. Needle retention of cuttings taken from the pretreated trees the following spring
was prolonged until September and the cuttings flushed, but did not root, whereas cuttings from untreated stock plants died
before September. No interaction between BA and SSHB was observed. When these pretreatments were repeated the following year
on the same mature clonal trees rooting of cuttings was significantly improved in the 5 ppm SSHB treatment.
Keywords:
adventitious rooting, auxin, brassinosteroids, clonal propagation, maturity, Picea abies.
