Submitted to: Biologia Plantarum
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/13/2005
Publication Date: 1/1/2007
Citation: Uzelac, B., Ninkovic, S., Smigocki, A.C., Budimir, S. 2007. Origin and development of secondary somatic embryos in transformed embryogenic cultures of medicago sativa l. cv. zajecarska 83. Biologia Plantarum. 51(1):1-6.
Interpretive Summary: When plants are genetically engineered for some trait, there is usually a very time-consuming process that is required to propagate large numbers of the new plants. We devised methods that enabled us to continually generate new embryos from genetically engineered and normal alfalfa cells that were grown in the laboratory. Over a three-year period, we microscopically examined the cells from both of these cell types and determined that there were no apparent differences in the origin or frequency of embryos that were generated from the genetically enhanced and normal cells. We conclude that this method could serve as a useful approach for rapidly producing large numbers of progeny from genetically engineered alfalfa plants. This information will be of interest to scientists working on increasing the number of progeny to quickly evaluate the potential of a newly incorporated trait in genetically enhanced plants.
Technical Abstract: Non-transformed and transformed embryogenic cultures of alfalfa (Medicago sativa L. cv. Zaje'arska 83), long-term maintained on growth regulator-free medium, were histologically analyzed. In all examined cultures, somatic embryos at various stages of development were observed and secondary embryos were formed in the cotyledonary, hypocotylary and radical region of the primary embryos. Detailed histological analysis of the torpedo shape somatic embryo revealed that secondary somatic embryos arose directly from single epidermal cells of hypocotylary axis. Initials of unicellular origin were formed after an unequal periclinal division. Bipolar proembryos were composed of one smaller cytoplasm rich cell and one larger more vacuolated cell. Further, cell division pattern was similar for both non-transformed and transformed embryos. However, multicellular origin of secondary embryos in a direct process and even from callus can not be excluded.