Shoots from Douglas-fir cultures

Abstract

Whole Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seed embryos were placed on defined medium containing 0.05 or 0.1 mg/ℓ BAP (benzylaminopurine). One vigorous shoot usually grew from the tip of each swollen cotyledon on the 0.05 BAP medium, but small multiple shoots were produced on the 0.1 BAP medium. After transfer of embryos or excised cotyledons to medium without hormones, the vigorous shoots developed normally but the small multiple shoots did not. However, when cotyledons were grown on medium containing auxin and cytokinin, callus was produced that was isolated and subcultured monthly to fresh medium. Shoots were produced from subcultured cotyledon callus in 11 of 35 cultures, for a frequency of 31%. Two of 30–50 excised shoots rooted after treatment with 10 mg/ℓ IBA (indolebutyric acid). A few shoots were also produced from subcultured needle callus and from stem explant callus from young seedling material.