Regeneration cell cultures and adsorption of the combined pdf and word

Cell cultures

1. Regeneration: Development of organized structures like roots, shoots, flower buds, somatic embryo or whole plant from cultured explants or calli derived from them . OR Genesis of an entire plant from cultured explants either directly or indirectly via callus.

2. Morphogenesis : Attainment of biological organization or form . In vitro (through PTC) this can be achieved by two routes: Organogenesis : Formation of individual organs such as shoots or roots. There are two ways Direct organogenesis: Developmental sequence without intervening callus stage. Primary explants----------» Meristemoid ----------» Organ Primordia b. Indirect organogenesis: Developmental sequence involves an intervening callus stage . Primary explants-----» Callus------» Meristemoid -----» Organ Primordia

3. 2 . Embryogenesis (Somatic/ nonzygotic ): Production of somatic embryo. There are two ways Direct somatic embryogenesis: Developmental sequence without intervening callus stage. Primary explants-----» Somatic embryo b . Indirect somatic embryogenesis: Developmental sequence involves an intervening callus stage. Primary explants-----» Callus-----» Somatic embryo

4. Organogenesis: In plant tissue culture it means the genesis of organs like shoots, roots, leaves etc. The development of shoot from explants is called as Caulogenesis ( Caulm = stem) The development of roots from explants is called as Rhizogenesis ( Rhizo = roots). Initially cell regions of high mitotic activity are formed called as merestemoids , further cell division in this merestemoids produces small protuberances on the surface of the calli giving nodular appearances to the tissue and from the primordial either root or shoot are formed.

5. Somatic embryogenesis: Somatic embryos are bipolar structures containing root and shoot axis with a closed independent vascular system and are produced from somatic cells. The developmental pattern of somatic embryo: Generally somatic embryo develops from single cell . Generally induction of somatic embryogenesis (induction of PEDC- Polyembryonically determined cell) in most species requires a high concentration of auxin (Generally 2,4-D) or a mixture of auxin and absiscic acid.

6. These PEDC divide irregularly to form Proembryonal complex (PEC) and then it divides and progress through different structural stages (globular, heart shaped, torpedo shaped, cotyledonary stage) to form Somatic embryo.

7. Stages of Somatic Embryogenesis

8. Application of somatic embryogenesis: Large number of plant clones can be obtained Regeneration potential is high compared to callus mediated regeneration Used in metabolite production under invitro condition. Some compounds are produced only in zygotes . Industrial lubricants from Zizypus jujuba , some lipid components of cocoa butter and compound oleopalmitostearin form Cocoa. Somatic embryo can be used for invitro screening as they are more sensitive to chemicals and antibiotics. Artificial or synthetic seeds can be produced

9. Limitations: They are highly genotype specific. Embryogenic potential decreases with time. Sometimes sterility is observed in plants generated through somatic embryogenesis. E.g. Maize, Oil palm In somatic embryo there is abnormal development under invitro condition.