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Plant Science & Biotechnology Objective: Summarize the chemical physical needs of plants of optimal growth. Chemical Needs of Plants Macronutrients needed for plant growth and development Nitrogen- encourages green color and vegetative growth in plants. Phosphorus- encourages flowering and root growth, necessary for reproduction and photosynthesis Potassium- important for the development of fruit and preparation of plants for winter Activates enzymes, and is more important in osmosis. Chemical Needs of Plants Micronutrients or trace Elements Needed by Plants Calcium, Molybdenum, Sulfur, Iron, Magnesium, Boron, Zinc, ect. Perform a variety of functions in plants- only small amounts are needed, but plants will die in their absence Chemical Needs of Plants Hormones- chemical substances that control physiological responses, including shoot and root growth. Examples: Auxins- Indole Butyric Acid (IBA), Indole Acetic Acid (IAA) Promotes the formation of adventitious root growth in stem cuttings. Cytokinins- Promotes adventitious shoot growth & elongation Gibberrellins- Breaks seed dormancy, stimulates flowering Physical Needs of Plants Water (H2O) Responsible for the transfer of nutrients, maintenance of temperature, preservation of turbidity, and necessary to carry out photosynthesis in plants. Absorbed by tiny root hairs scattered throughout the roots Large trees can absorb hundreds of gallons each day. Physical Needs of Plants Sunlight- absorbed by chlorophyll found in the chloroplasts of the leaves and stems of plants. Provides an unlimited source of energy for plants. Blue & red light spectrums are the most important in photosynthesis. Green light is reflected by chlorophyll, thus of little use for energy. High levels of ultraviolet light damage or destroy plant tissue Physical Needs of Plants Oxygen(O2)- plants need oxygen to produce energy and for the movement of nutrients through the plant Carbon Dioxide (CO2)- absorbed by plants for use in the process of photosynthesis Plant Science and Biotechnology Recognize how plants respond to environmental stimuli Factors affecting food Production Photoperiod-The amount of time a plant is exposed to adequate light energy. Even momentary disruptions of photoperiod can throw off the light cycle requirements of a plant Photointensity- The spectrum and strength of the light to which a plant is exposed. Too much light can be a bad thing and burns plants, while too little decreases food production. Factors affecting food Production CO2 Levels- needed for photosynthesis, like oxygen for humans, often the limiting factor in food production. Special generators are used to raise carbon dioxide levels in some production greenhouses. Factors affecting Plant Growth & Reproduction Oxygen prolonged exposure of the roots of most plants to stagnant water will eventually “suffocate” the plant, limit nutrient intake and stop production of new plants. Factors affecting Plant Growth & Reproduction Nutrients Both macronutrients and micronutrients are needed for plant growth and reproduction in various levels throughout the year. Excessive amounts of any nutrient can burn plants, destroy cells, or prevent the absorption of other nutrients. Factors affecting Plant Growth & Reproduction Geotropism- The directional growth of plant roots and stems in response to the force of gravity. Phototropism- The growth or response of a plant to varying light levels. Plant science & biotechnology UNIT E Objective: Explain the fundamentals of plant disease and infestation Intro to biotechnology Fungal Diseases Can affect any part of a plant- break down plant tissue. Easily spread by contract or spores. Often caused from the application of water on leaves with little airflow Intro to biotechnology Bacterial infection Often occurs in the form of blight Contaminated irrigation equipment is often a cause for the spread. Contaminated soil can also carry bacterial pathogens. Intro to biotechnology Insect Pests Three main types based on Mouth parts Sucking- damage plants by sucking juices from stems and leaves. Piercing Ex- Aphids, whiteflies, spider mites & mealy bugs Ex- leaf bugs & stinkbugs Chewing Ex- grasshoppers, beetle larva, cicadas Intro to biotechnology Japanese beetle larva and other grubs eat roots, while adult insects and moth larva (caterpillars/ worms in order lepidoptera) feed on foliage. Plant Science & Biotechnology Unit E Objective: Outline biological, chemical and physical methods of plant pest management. Integrated Pest management Program of observation and calculation used to maximize pest control while minimizing both damage and the use of harmful compounds and procedures. Limit pesticide damage to the environment. Scouting is critical, as observation allows treatment to proceed prior to a full blown infestation. Increase the effectiveness of all types of controlsparticularly non chemical treatments. Biological Controls Utilize naturally occurring compounds and substances to control plant pathogens Often more expensive, difficult to find, and requiring more frequent application than chemical methods. Increase the value of crops when utilized in place of chemicals. Chemical Controls Center on the use of pesticides, specifically herbicides, insecticides, miticides and fungicides used to kill pant pests Most current insecticides are Organophosphate chemicals that attack the nervous system of insects These chemicals quickly degrade preventing environmental buildup and transfer. (common to former pesticides like DDT) Chemical Controls Chemicals are synthetically manufactured in a variety of forms. Common forms dust, wettable powder, granular, liquid, foam. Systemic pesticides enter the plant, and are transferred to nearly all plant tissue. Usually kill either by contact or digestion. Ex- Malathion, Sevin Dust, Roundup, etc. Physical controls Hand removal, destruction or capture Often the most cost effective and environmentally friendly, but labor intensive and slow Traps Cost effective and environmentally friendly. Must be carefully monitored and instituted early to be effective EX Yellow sticky cards used to capture whiteflies and other small insects in a greenhouse. Japanese Beetle traps used pheromones (scented reproductive hormones) to capture adult beetles. Plant Science & Biotechnology Objective: Discuss the development and utilization of virus, herbicide, and insect resistant crops. Biotechnology and Plant pest control Creating Resistant plants Recombinant DNA can be used to create a resistant variety of nearly any type of plant, IF AN EDFFECTIVE GENE FOR RESISTANCE IS KNOWN The most effective method has been inserting gene sequences from other resistant organisms into a DNA of the target organism. The Bt gene & Bt crops The Bt gene is used to provide plants with systemic resistance to chewing insects responsible for damaging leaf tissue Functions by causing plants to produce to toxin, harmless to most organisms, but deadly to insect pests Causes internal bleeding in insect digestive systems. Herbicide Resistant Plants Plants that are not affected by the use of certain systemic herbicides. Allow production agriculturalists to apply pesticides more effectively, killing weeds without damaging plants. Virus Resistant Plants Few instances of successful implementation Usually functions by creating a protein coat around entire virus molecules. Prevent virus molecules from parasitizing normal cells Plant science & biotechnology Objective: Apply proper experimental design techniques related to field plot design and management Approval of field trials for transgenic Organisms Should be sought from APHIS Most often requires a significant amount of information produced from controlled trials in a contained environment. A plan for the trial, including practices to prevent the spread of genes from the organism must also be developed Agencies involved in the regulation and monitoring of transgenic organism fields trials include the USDA, EPA, & APHIS The FDA regulates GMO’s used in foods, but do no play any role in field trials . Implementing integrated Pest management Guidelines Plans should include as little dependence on harmful chemicals as possible. IPM does however utilize some chemicals, sometimes quite often. Biological and physical means of control are preferred. Implementing integrated Pest management Utilize VARYING & RESPONESIVE methods of control Most important part of IPM behind scouting, helps to insure that the overuse of one method of control does not produce insect resistance One reason for the use of buffer zones around Bt crops, so that resistant insects will breed with non resistant insects, preventing the development of resistant strains. Plant science & biotechnology Objective: Demonstrate proper techniques in the micropropagation of various plant tissue Selection Material for culture Selecting Material Only healthy actively growing material should be selected for use in tissue culture Meristimatic tissue from growth points and stem tips seems to work particularly well in small amounts Material should also be hardy/ resistant to decay, easy to manipulate and easily sterilized in solution. Selection Material for culture Sterilizing material Prior to use in tissue culture, all plant material must be sterilized. The most common means is to: Rinse plant material in sterile water for several seconds. Swirl plant material in a solution of diluted household bleach for a number of minutes. Remove plant material from bleach solution (under an active flowhood) and rinse several times with sterile water. Culturing Plant Material Steps in the culturing Process Prepare the agar media for use to be remelted in it container if shape has been compromised, Agar media should only be mixed and exposed to air under an active flowhood to prevent bacterial contamination. Place tissue on the media Place tissue firmly on agar media. In most cases, slightly one edge of the tissue to insure adequate contact with the agar, and limit movement. Tissue may be placed relatively close on agar, as shot and root development will be compact. Place tissue on the media POLARITY MUST BE MAINTAINED FOR SHOOTS, SCALES & OTHER CUTTINGS. Placing some plant material in media upside down will prevent the formation of either shoots or roots. Immediately following tissue placement all containers should be tightly sealed with the seal wrapped in perifilm decreased any risk of airborne contamination. Transfer of tissue After successful development of roots & or shoots, plantlets must be divided and with redistributed to new gels, or planted and placed in a controlled environment for hardening off. Most often plant material is encouraged to form shoots prior to the formation of roots. Agar high in cytokinins is used to promote shoot growth. Agar high in auxins is used to promote shoot root. Transfer of tissue Tissue should be carefully separate using a sharp sterile scalpel to cut apart shoots on a sterol petri dish under an active flowhood.