Method for reproducing conifers by somatic embryogenesis using stepwise hormone adjustment

US5236841A · kind A · utility

Inventors

• Pramod Gupta · Bedburg, DE
• Gerald S. Pullman · Renton, US

Key dates

• Filing date: May 24, 1991
• Grant date: Aug 17, 1993
• Expiry date: May 24, 2011

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C12N5/0025
• WIPO field: Biotechnology
• WIPO sector: Chemistry

Abstract

The invention is a method for reproducing coniferous trees by somatic embryo-genesis using plant tissue culture techniques in a multistage culturing process. A suitable explant, typically the fertilized embryo excised from an immature seed, is first cultured on a medium that induces multiple early stage proembryos. These are multiplied in a second culture having reduced growth hormones. The early stage embryos may then be placed in or on a late stage proembryo development culture with a significantly higher osmotic potential than the previous stage or stages in order to develop very robust late stage proembryos having at least 100 cells. Culturing from this point continues in a cotyledonary embryo development medium having a raised osmotic potential. Exogenous abscisic acid is now required at this stage. The concentration of abscisic acid is decreased over time to low levels either by the use of an adsorbent such as activated charcoal or by stepwise subcultures in which the later cultures have lower ABA concentration. After a period of several weeks somatic embryos having the appearance of zygotic embryos will have formed. These may be germinated before or after storage and transpl…