© 1986 Heron Publishing—Victoria, Canada
Influence of gibberellic acid and stock plant irradiance on carbohydrate content and rooting in cuttings of Scots pine seedlings
(Pinus sylvestris L.)
Arild Ernstsen (1) and Jürgen Hansen (2)
1. Institute of Biology and Geology, University of Tromsø, P.O. Box 3085 Guleng, N-9001 Tromsø, Norway / 2. Institute of Glasshouse Crops, Research Centre for Horticulture, Kirstinebjergvej 10, DK-5792 Årslev, Denmark / Received January 7, 1986
Summary
Seedlings of Pinus sylvestris L. were grown at three different irradiances (12, 30, or 60 W m–2) under a 17 h photoperiod. After six weeks, cuttings were excised and rooted at 30 W m–2. Gibberellic acid (GA3, 5 μl of 2 × 10–4 or 2 × 10–3 M) was applied to each cutting immediately after excision.
Cuttings from stock plants grown at the low irradiance rooted most quickly, whereas the highest number of roots per cutting
was obtained in cuttings from stock plants grown at 30 W m–2. Gibberellic acid delayed rooting and reduced the number of roots in cuttings from stock plants grown at 12, 30, or 60 W
m–2.
The initial carbohydrate content of cuttings increased with stock plant irradiance. For all carbohydrates, except myoinositol
and an unknown inositol derivative, the content per cutting increased during the first 28 days of rooting. The GA3 treatment significantly reduced the starch content of cuttings during the rooting period, but did not significantly change
the content of ethanol soluble carbohydrates.
