1、Chapter 14 Plant Biotechnology I. IntroductionA. Shrubs that “Glow in the Dark“B. Traditional and Modern BiotechnologyII. Traditional Vegetative PropagationA. Introduction1. Grafting Defined the permanent union of parts of two plants2. Ancient practicesa. Chinese practiced grafting by 1000 B.C.b. Th
2、eophrastus discussed grafting in his book, Causes of Plants,B. Stem Cuttings1. Cuttings defined pieces of a plant that are induced to produce roots and are then planted to grow on their own2. Example of navel oranges. First mutation originated in Brazil 1820. In 1873 it was shipped to Washington DC
3、then to Riverside, California 3. ProceduresC. Leaf Cuttings examples; African violets, peperomias, begoniasD. Root Cuttings,E. Layering1. Tip layeringa. Tips of stem (canes) in blackberries and boysenberries are covered with a mound of soilb. Roots and shoots form on the buried portionc. New plants
4、can be separated from parent stems2. Air layeringa. Wounded stem is wrapped in damp sphagnum moss and covered with plastic filmb. Adventitious roots develop from injured areas on stemc. Cut stem below root growth and plant in soil,F. Propagation from Specialized Stems and Roots1. Rhizomes, tubes, an
5、d corms divided and grow into new plant2. Bulbs hyacinth, grape hyacinth induced to form bulblets by wounding3. Fleshy storage roots sweet potatoes, dahlias,III. GraftingA. Grafting Process insertion of a short stem portion, the scion, into another stem, the stock, containing a root systemB. Grafted
6、 Part Must Be Related can not graft maple wood to an apple tree,IV. Traditional Plant BreedingA. The Green Revolution1. Defined development of high yielding strains of wheat and other grains2. Norman Borlauga. “Father of the Green Revolution“b. Awarded Nobel Prize in 1970 for developing new strains
7、of wheat in Mexico3. Drawbacksa. Plentiful water supply required (i.e., irrigation water)b. Extensive applications of fertilizer required,B. Hybridization1. Crossing of different varieties yield F1 seed with hybrid vigor2. Corn grown in North America comes from F1 hybrid seed3. Bread wheat hybrids,C
8、. Polyploidy1. Defined flowering plants that have more than two sets of chromosomes2. Typesa. Alloploidy hybridization followed by a doubling of the chromosome numberb. Autoploidy chromosomes doubled when pairs of chromosomes fail to separate during mitosis or meiosis3. Artificially creating polyplo
9、idsa. Treating seeds with colchicine interferes with spindle formation during mitosisb. Wounding and callus formation e.g. tomatoc. Application of heat to seeds e.g. corn,D. Mutations1. Defined involves a change in a gene or chromosome2. Induced mutationsa. Radiationb. Chemicals3. Usefulness of muta
10、tions some induced mutations have yielded better strains of Penicillium mold,V. Tissue Culture and MericloningA. Tissue Culture1. Defined a mass of callus tissue growing on an artificial medium2. Techniquesa. Isolate plant tissues from meristems or pithb. Place in sterile growth mediumc. Rapid multi
11、plication of cells occursd. Tissue may differentiate into roots, shoots, or plant embryos3. Crop improvement through tissue culturea. Can select desirable traits from large population of cellsb. Can subject cells to stresses such as herbicides, heat, cold, etc., then select the survivors that are re
12、sistant to applied stress,B. Shoot Meristem Culture (Mericloning)1. Defined growth of a new plant by removing the apical meristem and placing it on sterile growth medium2. Advantages tissue growth can be subdivided and cultured to yield many identical plants3. Examples orchidsC. Artificial Seeds1. G
13、enetically identical embryos are mass-produced through tissue culture2. Embryos packaged with a food supply, hormones, and a biodegradable protective coat3. Identical plants produced which may lessen the expense of harvesting the crop,D. Protoplast Fusion1. Cell walls are digested which leaves naked
14、 protoplasts2. Protoplasts minus their walls can then fuse or hybridize3. Hybrid cells can be selected for and cultured4. Somatic hybrids are the result of a fusion from two different protoplastsE. Clonal Variants1. Cells with slightly different characteristics are frequently found in cultures2. Var
15、iant cells are grown into desirable plants in a shorter time than normal plant breeding techniques would permit,VI. Genetic Engineering or Recombinant DNA TechnologyA. Process of Genetic Engineering1. Remove a gene from its normal location2. Insert gene into a circular form of bacterial DNA called p
16、lasmid DNA3. Plasmid DNA carrying gene is transferred into cells of another speciesB. Isolation of Plasmid DNAC. Restriction Enzymes1. From bacteria2. Break a circular plasmid at a specific nucleotide sequenceD. Repair Enzymes1. Called DNA ligases2. Links two fragments of DNA together,E. Instruments
17、 that Facilitate Gene Cloning1. Protein sequencer can determine the amino acid sequence of a protein2. Gene synthesizer can synthesize specific nucleotide sequences of a geneF. Polymerase Chain Reaction (PCR) Technology,G. Cell Bombardment and Electroporation1. Cell Bombardmenta. Shoot DNA-coated pa
18、rticles into plant cellsb. 2% of bombarded cells take up foreign DNA2. Electroporationa. Cells placed in an electrical fieldb. Cell wall becomes permeable to admit foreign DNA,H. Other Applications of Genetic Engineering1. Early Experimentsa. Transgenic mice (1980) foreign gene introduced into ferti
19、lized mouse eggsb. Transgenic plants gene from French bean transferred to cell of sunflower plant, called “sunbean“,2. Later Developmentsa. Herpes virus vaccineb. Hepatitis B vaccine produced in plantsc. Genetically engineered pesticided. Genetically altered canolae. Insect resistant seedsf. White b
20、lood cells with “tracking“ gene injected into terminal cancer patientsg. Sun lotion to protect against cancer-causing radiationh. Flavr Savr tomato (Calgene, Inc., Davis, California) first engineered food product to reach market (1994)i. Rust resistance beansj. Antifreeze gene from Antarctic fish,I. A Few Pros and Cons of Genetic Engineering1. Fear of release in the environment of genetically altered species2. Promise of genetically altered plants that require less herbicides3. Promise of improved human quality of life with genetically engineered products,
