Kim YW et al., Plant Biotechnol Rep 1:237–242 (2007)
Summary
We have tested plantlet formation by somatic embryogenesis using immature seeds of Magnolia obovata. Seed collection date appeared to be critical for embryogenic cell induction. The optimal collection date was 3–4 weeks postanthesis. The embryogenic cells proliferated, formed somatic embryos, and were subsequently converted into normal plantlets under optimized culture conditions. Somatic embryo formation from the embryogenic calli was better on sucrose medium than on glucose medium. The optimum level of sucrose appeared to be 3% with an average of 28 somatic embryos per plate. About 25% of somatic embryos were converted into normal plantlets in 1/2 MS medium containing gibberellic acid (GA3). During somatic embryo germination, secondary embryogenesis was frequently observed in the lower part of the hypocotyl or radicle ends of germinating somatic embryos. Finally, about 85% of converted plantlets survived in an artificial soil mixture, were transferred to a nursery, and have grown normally.
Objectives
This study was conducted to develop a micropropagation technique for the species using somatic embryogenesis.
Materials
In 2003, developing fruits (aggregates of follicles) were collected, at about 10-day intervals, from 3 to 7 weeks postanthesis, from three trees growing on the campus of Seoul National University, Suwon, Korea.
Explant
Individual seeds were dissected from the aggregates using a surgical knife and disinfested using the sequence: 70% ethanol, 30 s; 2% sodium hypochlorite 10 min; rinsing four times with sterile distilled water. Seeds were bisected longitudinally with a scalpel and the halves were placed cut, surface downward, on 25 mL semisolid callus induction medium
Initial culture
Seeds were bisected longitudinally with a scalpel and the halves were placed cut, surface downward, on 25 mL semisolid callus induction medium
Shoot multiplication
Using early-cotyledonary-stage SEs, embryo germination was performed on 1/2 MS medium with 1.0 mg/L GA3 and two different gelling agents
Rooting
Acclimation
Normally converted plantlets were transferred to plastic rectangular boxes (40×70×20 cm) containing a mixture of artificial soil (peatmoss–vermiculite–perlite, 1:1:1) and cultivated in a greenhouse