can affect division, elongation, & differentiation of cells to another region of plant where they have an effect

Transcription

1 Note that the following is a rudimentary outline of the class lecture; it does not contain everything discussed in class. Plant Hormones Plant Hormones compounds regulators growth or can affect division, elongation, & differentiation of cells effective at very concentrations synthesized in one region of plant to another region of plant where they have an effect Interact with tissues to causes changes such as growth & fruit ripening may have a in different parts & types of plants Main groups or classes usually many similar hormone molecules in group Abscisic Acid leaves, stems, Effects generally inhibits other dormancy ensures that the seed will germinate only when there are optimal conditions dormancy

2 helps the plant withstand stressful conditions Lecture 6 - Hormones, drought tolerance Auxins embryo of seed, meristems of Effects promotes plant Acid growth hypothesis stimulates lateral & adventitious increased cell division in cambium & influences differentiation of secondary many herbicides are when applied at higher (but still relatively low) concentrations cause abnormal leaf curling & eventually plant death e.g. Cytokinins transported to other Effect affect growth & differentiation stimulate division & growth BIOL

3 dominance Lecture 6 - Hormones, stimulate delay anti-aging effect Apical Dominance ability of a terminal bud to of axillary buds control of dominance,, and other factors interact if the terminal bud is plants become Cytokinins Cytokinins retard of some plant organs by inhibiting protein breakdown stimulating RNA & protein synthesis mobilizing nutrients from surrounding tissues e.g: Gibberellins of apical buds & roots, young, embryo Effects promote germination Barley seed germination stem & leaf growth stimulate flowering & BIOL

4 development of affect root growth & Steps in Barley Seed Germination Seed imbibes water Embryo releases hormones Gibberellins (GA) Stimulate aleurone layer fruit Lecture 6 - Hormones, thin outer layer of the endosperm Aleurone synthesizes and secretes digestive enzymes α-amylase - hydrolyzes starch Enzymes hydrolyze stored foods in the endosperm produce small, soluble molecules Scutellum absorbs sugars and other nutrients from endosperm Sugars are consumed during growth of the embryo into a seedling Gibberellins used commercially to produce fruit e.g. Ethylene tissues of fruits, nodes of stems, leaves and flowers Effects promotes fruit opposes some effects BIOL

5 Lecture 6 - Hormones, promotes or inhibits growth & development of, depending on species e.g. the study of interactions between all aspects of an organism's surroundings 1. Biotic ( ) 2. Abiotic ( ) Environment Biotic environment all organisms that an individual interacts with same different different who eats who, who helps who, who hurts who? these interactions Determine both the of organisms & their Abiotic environment the chemical and physical components of the environment Climatic BIOL

6 Edaphic ( ) Lecture 6 - Hormones, Organismal Population Community Ecosystem Landscape Biosphere Dividing lines between these levels are sometimes fuzzy studies how an organism s structure, physiology, and (for animals) behavior meet the challenges posed by the environment concentrates mainly on factors that affect how many individuals of a particular species live in an area deals with the whole array of interacting species in a community Emphasizes energy flow and chemical cycling among the various biotic and abiotic components Deals with arrays of ecosystems and how they are arranged in a geographic region BIOL

7 Lecture 6 - Hormones, Deals with all ecosystems & atmosphere & hydrologic cycle Controls and patterns of worldwide circulation of energy and nutrients Examine some aspects of Community ecology Biosphere ecology Chains Categorize the organisms in a biotic community on the basis of the kind of utilized Link the trophic levels from Terrestrial food chain Marine food chain Web Can t always categorize organisms neatly a branching food chain with complex trophic interactions Trophic Relationships Energy flows through an entering as & exiting as Energy and nutrients pass from level to level BIOL

8 Trophic Levels Lecture 6 - Hormones, 4th Trophic Level Tertiary Consumers 3rd Trophic Level Secondary Consumers 2nd Trophic Level Primary Consumers 1st Trophic Level Primary Producers Energy & Nutrient Dynamics Trophic Efficiency the percentage of production transferred from one trophic level to the next usually ranges from % to % assume an average value of % loss of energy with each transfer in a food chain can be represented by a of net production Ecological Pyramid Trophic Efficiency Most pyramids show a sharp decrease at successively higher trophic levels A pyramid of represents the number of individual organisms in each trophic level Pyramids General Model of Chemical Cycling BIOL

9 Lecture 6 - Hormones, gaseous forms of,, sulfur, & nitrogen occur in the atmosphere & cycle globally less mobile elements, including, potassium, & cycle on a more local level Includes the main reservoirs of elements and the processes that transfer elements between reservoirs All elements cycle between organic & reservoirs Biogeochemical Cycles Global cycles Water cycle H 2 O moves in a driven by energy Carbon cycle reflects the reciprocal processes of and Localized cycles Nitrogen cycle involves local cycles between Phosphorus cycle relatively BIOL