Norway spruce somatic embryogenesis: high-frequency initiation from light-cultured mature embryos

Abstract

Somatic embryos and rooted plantlets have been regenerated from light-initiated embryogenic callus derived from mature embryos of Picea abies. Under a 16 h photoperiod, mature zygotic embryos were cultured on a modified half-strength Murashige & Skoog medium without NH4 NO3 and supplemented with 5 mM glutamine, 4.5 pM N6-benzyladenine and 10.7/tM naphthaleneacetic acid or 10 #M 2,4-dichlorophenoxyacetic acid. White translucent embryogenic callus, proliferating from the callusing hypocotyl region after 3 weeks incubation, was isolated from the green non-embryogenic tissue and subcultured for over 12 months. Upon transfer of the embryogenic callus through a specific sequence of media, somatic embryos proceeded to mature, elongating and forming rings of cotytedonary leaves similar to those of zygotic embryos. Transferred to medium without growth regulators, the somatic embryos 'germinated' and produced plantlets with green cotyledons, elongated hypocotyls and primary roots.

Brassinolide improves embryogenic tissue initiation in conifers and rice

“…Shortly after sterilization, the seeds were dissected and the integuments and nucellus removed. The female gametophyte was carefully split, the embryo removed, and the embryo and split gametophyte placed next to each other on 10 ml of Verhagen and Wann (1989) initiation medium (medium 56, Table 1) contained in a 15-ml petri plate. Fifty seeds were tested per medium supplemented with 0 mM or 0.1 mM brassinolide and incubated at 23-24C under a 16/8-h (day/night) photoperiod with light supplied by cool-white fluorescent lamps at an intensity of 538 lux.…”

Morphogenic Aspects of Somatic Embryogenesis

“…In Norway spruce, embryogenesis was possible only in complete darkness if ammonium is present in the medium. The removal of ammonium was necessary before embryogenesis is possible in the light [86]. Red light enhanced while blue light decreased the induction of date palm [87] somatic embryos.…”

Somatic embryogenesis in Araucaria angustifolia

“…As a maturation medium, the following combinations were investigated: a) ½ BLG (Verhagen and Wann 1989) supplemented with 0.05 g dm -3 L-asparagin, 0.75 g dm -3 L-glutamine, 7.5 % (m/v) polyethylene glycol (PEG) 4000, 30 g dm -3 maltose, 3 g dm -3 Gelrite ® , and different concentrations of abscisic acid (ABA; 0, 5, 15, 40, 80, 120, 240 μM) b) MSG supplemented with 1.46 g dm -3 L-glutamine, 6 % (m/v) PEG 3350, 60 g dm -3 maltose, 30 g dm -3 sucrose, 3 g dm -3 Gelrite ® , and ABA (0, 15, 40, 80 μM). EC were maintained in the dark at 25 ± 2 °C and subcultured every 8 weeks.…”