1 / 69

Somatic Embryogenesis

Somatic Embryogenesis. Parthenocarpy Apomixis In vitro somatic embryogenesis. Soybean – Wayne Parrot, UGA. Somatic Embryos. Bipolar Not connected to explant or callus cells by vascular tissue In most woody plants, tissue must be juvenile or reproductive. Indirect Somatic Embryogenesis.

Télécharger la présentation

Somatic Embryogenesis

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.


Presentation Transcript

  1. Somatic Embryogenesis • Parthenocarpy • Apomixis • In vitro somatic embryogenesis

  2. Soybean – Wayne Parrot, UGA

  3. Somatic Embryos • Bipolar • Not connected to explant or callus cells by vascular tissue • In most woody plants, tissue must be juvenile or reproductive

  4. Indirect Somatic Embryogenesis

  5. Induction • Auxins required for induction • Proembryogenic masses form • 2,4-D most used • NAA, dicamba also used

  6. Development • Auxin must be removed for embryo development • Continued use of auxin inhibits embryogenesis • Stages are similar to those of zygotic embryogenesis • Globular • Heart • Torpedo • Cotyledonary • Germination (conversion)

  7. Maturation • Require complete maturation with apical meristem, radical, and cotyledons • Often obtain repetitive embryony • Storage protein production necessary • Often require ABA for complete maturation • ABA often required for normal embryo morphology • Fasciation • Precocious germination

  8. Germination • May only obtain 3-5% germination • Sucrose (10%), mannitol (4%) may be required • Drying (desiccation) • ABA levels decrease • Woody plants • Final moisture content 10-40% • Chilling • Decreases ABA levels • Woody plants

  9. Rubber tree from somatic embryoCIRAD

  10. Factors that Influence SE • Genotype • Growth regulators • Carbon source • Nitrogen

  11. Maturation and Germination(Conversion)

  12. Micropropagation “… the art and science of multiplying plants in vitro.”

  13. Rapid clonal in vitro propagation of plants: • from cells, tissues or organs • cultured aseptically on defined media • contained in culture vessels • maintained under controlled conditions of light and temperature

  14. Toward Commercial Micropropagation 1950s Morel & Martin 1952 Meristem-tip culture for disease elimination

  15. Commercialization of Micropropagation 1970s & 1980s Murashige 1974 Broad commercial application

  16. Clone Genetically identical assemblage of individuals propagated entirely by vegetative means from a single plant.

  17. Conventional Propagation • Cuttings • Budding, grafting • Layering

  18. Conventional Propagation Advantages • Equipment costs minimal • Little experience or technical expertise needed • Inexpensive • Specialized techniques for growth control (e.g. grafting onto dwarfing rootstocks)

  19. Micropropagation Advantages • From one to many propagules rapidly • Multiplication in controlled lab conditions • Continuous propagation year round • Potential for disease-free propagules • Inexpensive per plant once established

  20. Micropropagation Advantages • Precise crop production scheduling • Reduce stock plant space • Long-term germplasm storage • Production of difficult-to-propagate species

  21. Micropropagation Disadvantages • Specialized equipment/facilities required • More technical expertise required • Protocols not optimized for all species • Plants produced may not fit industry standards • Relatively expensive to set up?

  22. Micropropagation Applications • Rapid increase of stock of new varieties • Elimination of diseases • Cloning of plant types not easily propagated by conventional methods (few offshoots/ sprouts/ seeds; date palms, ferns, nandinas) • Propagules have enhanced growth features (multibranched character; Ficus, Syngonium)

  23. Explant • Cell, tissue or organ of a plant that is used to start in vitro cultures • Many different explants can be used for micropropagation, but axillary buds and meristems are most commonly used

  24. Choice of explant • Desirable properties of an explant: • Easily sterilizable • Juvenile • Responsive to culture • Importance of stock plants • Shoot tips • Axillary buds • Seeds • Hypocotyl (from germinated seed) • Leaves

  25. Methods of micropropagation >95% of all micropropagation Genetically stable Simple and straightforward Efficient but prone to genetic instability Little used, but potentially phenomenally efficient • Axillary branching • Adventitious shoot formation • Somatic embryogenesis

  26. Axillary shoot proliferation Growth of axillary buds stimulated by cytokinin treatment; shoots arise mostly from pre-existing meristems

  27. Shoot Culture Method Overview • Clonal in vitro propagation by repeated enhanced • formation of axillary shoots from shoot-tips or • lateral meristems cultured on media • supplemented with plant growth regulators, • usually cytokinins. • Shoots produced are either rooted first in vitro • or rooted and acclimatized ex vitro

  28. ADVANTAGES • Reliable rates and consistency of shoot multiplication • 3 -8 fold multiplication rate per month • Pre-existing meristems are least susceptible to • genetic changes

  29. mericloning  A propagation method using shoot tips in culture to proliferate multiple buds, which can then be separated, rooted and planted out

  30. First commercially used with orchids - conventional propagation rate of 1 per year. • Through protocorms, 1,000,000 per year. Corm (Swollen stem) Chop into pieces Maturation

  31. Axillary shoot production • Selection of plant material • Establish aseptic culture • Multiplication • Shoot elongation • Root induction / formation • Acclimatization

  32. Selection of plant material • Part of plant • Genotype • Physiological condition • Season • Position on plant • Size of explant

  33. Physiological state - of stock plant • Vegetative / Floral • Juvenile / Mature • Dormant / Active • Carbohydrates • Nutrients • Hormones

  34. Stage 1

More Related