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The Three Pillars of Yield BREEDING Strategically breed plants to create new, more robust seeds that perform better – and longer – in the field. AGRONOMICS Use precision ag, planting density, plant health protection, and conservation tillage to make acres more productive. BIOTECHNOLOGY Supplement breeding advancements by adding special beneficial genes to the plant. ALL THREE ARE CRITICAL IN DELIVERING YIELD TODAY – AND In Vitro Culture The culture of organized living material cell under artificial condition in tubes, glasses, dishes The process of growing organized living materials artificially in the laboratory The culture and maintenance of organized living materials, in sterile, nutritionally (synthetic media) and environmentally (controlled) supportive conditions Organized living material Homogeneous (tissues) Heterogeneous (organs) Tissue Hooke (1665) and Leeuwenhoek (1677) using microscope discovered tissues were made of cells Cells The cells of a particular tissue had a common structure. Cell Taken to its simplest form A plasma membrane… Surrounding cytoplasm… Containing hereditary material. Level of complexity Xavier Bichat (1771-1802): An organ is composed of different tissues Several organs can be grouped together as an organ system (e.g. the digestive system) Organism Organsystem Organ Tissue Cell Level of complexity Purkinje (1835) Observed a fertilised hen's egg (a single cell) could develop into an embryo (many specialised cells in a compact mass) C19th botanists showed that plant tissues consist of many different types of cells. THE CELL THEORY Schleiden (1838) & Schwann (1839) “The cell is the basic unit of living tissue” The cell is an autonomous unit (“a citizen”) grouped together to form an organism (“the society”). « Omnis cellula e cellula » Virchow (1858) “all cells come from pre-existing cells” Cell culture The process by which prokaryotic, eukaryotic or plant cells are grown under controlled conditions. Cell culture was first successfully undertaken in animal cell by Ross Harrison (1907) and in plant cells by Haberlandt (1902) ORGANISMAL THEORY Reichert (a morphologist): An organism has a structured plan Image Credit Frog embryo fate map Plasmodesmata Strasberger (a cytologist): Cells are connected in an organism sometimes by cytoplasmic bridges Acellular organisms Some organisms do not have cellular compartments Unicellular organisms Some organisms only consist of a single cell But these do usually have the cell components (nucleus, membrane, etc) Tissue culture In vitro cultivation of organs, tissues & cells at defined temperature using an incubator & supplemented with a medium containing cell nutrients & growth factors Cells can be cultured away from a body But this often requires elaborate support systems (technology) Organized living material 1.Animal Cells 2.Plant Cells Plant Tissue Culture Plant Tissue Culture “the aseptic culture of plant protoplasts, cells, tissues or organs under conditions which lead to cell multiplication or regeneration of organs or whole plants “ Totipotency …. each living cell has a complete genetic blueprint and therefore has the potential to develop into an entire plant. … cells differentiate … animal cells, plant cells can … unlike living plant cells canliving re-differentiate de-differentiate and then re-differentiate to form different cell types Early Plant Cell Culture …Haberlandt .. early 1900’s … proposed concept of totipotency … cells cultured under right conditions Callus cultured from tree cambium Gautheret et al. (1930). … cells kept alive but did not develop Early Plant Tissue Culture - dependent on discovery of “growth regulators” Cell enlargement … role of auxins Cell division ... role of cytokinins Regeneration from tobacco pith .. (Skoog and Miller) … interaction of auxin and cytokinin gives differentiation. Carrot plants from root cells (Stewart, 1964) Tobacco plants from single cells (Vasil & Hilderbrandt, 1965) Requirement Appropriate tissue (some tissues culture better than others) A suitable growth medium containing energy sources and inorganic salts to supply cell growth needs. This can be liquid or semisolid Aseptic (sterile) conditions, as microorganisms grow much more quickly than plant tissue and can over run a culture Growth regulators, both auxins & cytokinins. Frequent sub-culturing to ensure adequate nutrition and to avoid the build up of waste metabolites Course Outline Introduction to in vitro culture Determining factors in plant tissue culture Micropropagation Pattern of development Micropropation enterprice