Survival and Regeneration of Somatic Embryos of Juglans regia L. (English Walnut) after Being Frozen in Liquid Nitrogen

1989

S. 159-165

2 Abb., 2 Tab., 34 Lit. Ang.

Unselbständiges Werk

200067857

The develop methods for long term storage of walnut somatic embryos, the somatic embryois of 4 cultivars established from the immature cotyledons of open-pollinated seeds of Juglans regia L. were treated with a cryoprotective either mixture 10% (w/v) of polyethylene glycol (P), 8% (w/v) glucose (G) and 10% (w/v) dimethyl sulfoxide (D, DMSO) or 10% (w/v) DMSO alone frozen at 1C/min to -30C, and then plunged into liquid nitrogen (LN) for 10 min. After storage in LN samples in polypropylene freezing tubes were thawed rapidly in a water bath at 40C, rinsed with a liquid DKW medium and placed on a basal subculture medium lacking growth regulators solidified with the gelrite (Merck Co.) at 0.24% (w/v) for growth comparisons. Growth subsequent to treatment was measured as increasing fresh weight at one week intervals. Following treatments, in Scharsch-Franquete (Formel) cultivar, the fresh weight of unfrozen somatic embryos increased slowly until 3 weeks in culture, thereafter regrew rapidly, whereas post-thawed embryo regrowth was inhibited initialy by up 2 weeks, then they began to regrow at approximately the same rate as unfrozen. The frequency of survival was relatively low in frozen embryos (below 40%) compare with unfrozen (over 90%), but no significant difference between them in production of new embryois (30%) with a excepting unfrozen PGD (50%). Treating the somatic embryos of three cultivars with PGD, SF-2 cultivar survived 10% of embryos after immersion in liquid nitrogen, and they regenerated progeny embryos. Results suggest that preservation of germplasm for future tree improvement may be possible via liquid nitrogen storage of walnut somatic embryos but more effective method development is needed.