Plant science & Biotechnology

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. • Ex- Aphids, whiteflies, spider mites & mealy bugs • Piercing • 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 controls- particularly 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, ect

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.

Plant science & Biotechnology