HORT 100 Exam 2 Study Guide
HORT 100 Exam 2 Study Guide HORT 100-001
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This 18 page Study Guide was uploaded by Erin Wade on Tuesday October 18, 2016. The Study Guide belongs to HORT 100-001 at Colorado State University taught by Hughes, Harrison G in Fall 2016. Since its upload, it has received 24 views. For similar materials see Horticultural Science in Agriculture / Horticulture at Colorado State University.
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Date Created: 10/18/16
Exam 2 Study Guide Plant Propagation - Sexual propagation (seed propagation is not exactly the same as sexual propagation, because of apomixis) - Asexual propagation (vegetative) - Seed Formation ● Life cycle of a typical plant - ● Megasporogenesis - formation of megaspores inside the ovules, diploid cell in ovule or mother cell undergoes meiosis, and produces four haploid megaspores ● Microsporogenesis - formation of microspores in microsporangia (pollen sacs). Diploid cell in microsporangium or mother cell undergoes meiosis, and produces four haploid microspores ● Double fertilization - joining of female gametophyte with two male gametes ● Zygote - used product of the fusion of two haploid gametes - a fertilized ovum ● Embryo formation - sperm (1N) unites with egg (1N) to produce diploid (2N) embryo ● Food storage material - endosperm ● Seed coverings - protects rest of seed ● Apomixis - not true sexual propagation - Seed storage and viability ● Storage ○ Recalcitrant - highly hydrated when they shed from the plant and ready to germinate, die if stored for long periods of time ○ Orthodox - everything else, relatively dry at time of maturity, stay alive in dry environment ■ Different ranges of time that different seeds can survive ● Viability ○ Float test - determine whether a seed has an embryo and nutrients in it still, if it sinks it is still good ○ Standard germination - tests to determine germination time and seed quality/viability ○ Tetrazolium stain - soak seeds and living seeds will take in the stain ○ Excised embryo test - use for woody plants, excised and incubated and they either grow or decay - Seed dormancy ● Seed coat dormancy - limits gas and water exchange ○ Scarification tmt - damage seed coat using acid, then plant and it wil germinate ● Embryo dormancy - something on the interior is not allowing it to germinate ○ Stratification tmt - hold seed for 6-8 weeks in cool moist condition, breaks down natural chemicals and releases dormancy ● Double dormancy - both seed coat and embryo are dormant ● Rudimentary dormancy - secondary dormancy, where it goes back to being dormant after starting to germinate and not getting enough water ● Chemical inhibitors - slows down reaction ● Why does dormancy occur? ○ In nature these seeds might fall into moist conditions (stratification), it might get washed out and scrape against rocks or break (scarification) ○ Only germinates in wet conditions to make sure the plant will get enough water - Environmental factors ● Quiescent - seeds are resting and waiting for right conditions, but not dormant ● Water - have sufficient water for seed to absorb (60% water in seed) ● Temperature - not too extreme ● Aeration - not just in air, need to respire ● Light - some plant are inhibited by light, others require light ● Freedom from disease and salts - salts reduce moisture, not enough for plant - Seed Certification ● Breeders seed - most pure seed, held by seed company or originator of cultivar, strictly handled ● Foundation seed - offspring of breeder seed ● Registered seed - offspring of breeder or foundation seed and used to produce certified seed ● Certified seed - relative quality is ensured to be able to sell to growers - Planting Seeds ● Mechanization seeding - using machines to do labor intensive planting ○ Seed coating - coating seeds to make them round so that they can be handled more easily, pass through mechanical apparatus and be separated and planted one at a time ● Seeding for plugs - clumps of dirt with seeds in it that can be sold and distributed ○ Seed priming - prepare seed to germinate correctly using enzyme treatment ○ First paper on priming published by someone at CSU Seed Plugs Coated seeds Basis for Aesexual Propagation - Maintain specific genotype, because it has the exact genes we want - May be the only means of propagation for some plants if the seeds have been bred out - May be faster than using seeds, because they can skip the juvenile stage - Create usual forms, they are all uniform Juvenile plants vs. Adult plants - Juvenile plant is incapable of reproducing - doesn’t produce seeds or flowers - Juvenile plant might need support to stay upright - Concepts of maturation ● Ontogenetic - origination and development of an organism ● Homoplastic - leaves are all very similar ● Heteroblastic - leaves start to differentiate - Chimera - organism that contains more than one genotype, mixture of genetically different materials (each layer is genetically different) ● L1 layer - epidermis ● L2 layer - more complex - cortex, part of vascular system, gametes ○ Divides horizontally and vertically ● L3 layer - bulk of vascular system and pith tissue(cross section of stem) ○ Divides horizontally and vertically Ex of chimeras Cutting Propagation - Stem cuttings ● Remove lower leaves from a cutting, so they are not in direct contact with dirt/water and they don’t rot ● Herbaceous - non-woody plants ● Softwood - new growth on woody plants, spring/summer ● Semi-hardwood - partially mature wood, summer/fall ● Hardwood - dormant mature stems, late fall/winter/early spring - Root cuttings ● Used for certain species ● Ex: aspens - Leaf/bud cuttings Layering - Letting a plant root while still attached to the mother plant, maintains moisture through connection while rooting - Blanching - depriving of light after it started growing in light, less differentiation in cells ● Air layering - make cutting from plant and surround cut with moss with as little moisture as possible, or slit the stem and put moss around it ● Tip layering - bend a stem to ground and put dirt over it, this induces root growth in the bend of the stem and the tip grows upwards again ● Mound layering - cut stems back from shrubby plants and mound dirt over it, then new shoots will root at their bases ● Trench layering - Mother plant is planted at an angle, so that new little plants can have dirt put over them in a trench in order to separate them - Stems that propagate by natural layering ● Stolon (runners) - produce new shoots where they touch the growing medium, plantlets can be rooted while still attached to mother plant or can be detached ○ Ex: Spider plant ● Rhizome - main stem growing horizontally ● Tuber - fleshy stem below ground that holds stored nutrients ● Bulb - form next to the old bulbs underground, stored nutrients ● Corm - large corm forms on top of old corm, corms don’t have fleshy scales like bulbs Micropropagation - Terminology ● Plant tissue culture - technique used to grow plant cells/tissues/organs in sterile conditions in a nutrient medium ● Shoot tip culture - culture using the tip ● Explant - transfer living cells/tissues/organs to a nutrient medium - Stages of Micropropagation ● Stage I - growing plantlets in tissue culture ● Stage II - proliferation, multiplying shoots ● Stage III - separate and root ● Stage IV - establish plants outside of test tube - Somaclonal variation - variation in progeny resulting from somatic tissue cloning ● Callus - mass of undifferentiated tissue, primarily collenchyma cells ● Agar - jelly like substance taken from algae - Production of virus-free plants - Protocorms/orchid production Grafting - Reason/basis for grafting - to propagate a plant that may not be rooted by its cuttings, adapt a plant to a different soil, create resistance to a pathogen - Do cuttings and grafts during dormancy - Scion - young shoot or twig cut for grafting - Splice graft ● Slant cut and tie the two pieces together - Whip and tongue ● Cut a sort of lightning shape and fit the two pieces together - T bud ● Bud is attached to root stock ● Bark has to be slipping - vascular cambium is actively growing and can be pulled easily from the stock without too much damage - Cleft graft ● Insert two scions into the sliver of a rootstock that is much larger than the scions - Budding ● T-budding ● H-budding - same as T-budding, except you cut and H - Bridge graft - to repair trees that have been girdled around the trunk (damaged where the bark is removed around the tree) by mice or rabbits, or machinery ● Scions are used to bridge the gap in bark by slipping the ends under the bark - Inarching - to repair trees that have been girdled around the trunk (damaged where the bark is removed around the tree) by mice or rabbits, or machinery as well as on the roots ● Plant the scions around the tree and then slip the top end of the scions under the bark of the tree so that they create sort of new roots for the damaged tree Inarching Bridge grafting - What plants can be grafted - Incompatibility mechanisms ● Localized incompatibility - scion in contact with rootstock don’t work out, but you can put something else between them to make it work (interstock) ● Translocated incompatibility - When you use an interstock that should be mutually compatible with both the rootstock and the scion, but it still doesn’t work because there is something that travels between that is not compatible Life Cycle - Growth ● Indeterminate - keeps growing after important structures are formed ○ Ex: pole beans ● Determinate - growth stops once important structures are completely formed ○ Ex: bush beans ● Terminal Flowering Plant - Environment ● Light - critical, can manipulate growth by providing more or less light ○ Phototropism - plant grows towards light ○ Light influences time of flowering ○ Solarization - sunburn on leaves or fruit ○ Absence of light - pale and softer tissue ■ Asparagus that is a little hard and woody at the bottom has been in the light and grown a little too long, but white asparagus grown without light is very nice and soft, more expensive ● Temperature - some do better in cooler or warmer temps ○ Vernalization - cooling a seed during germination to induce flowering more quickly once they start growing ○ Chilling - plants have different requirements for the amount of time they have to be chilled before they will bloom ■ Flower already exists, but chilling helps it bloom ■ Ex: low chill peaches - have to get cold in order to be released from dormancy and grow ○ Freezing injury vs. chilling injury ■ Chilling injury is damage to a plant that occurs above freezing point (32℉/0℃) ■ Freezing injury occurs when temperatures drop below freezing point ● Moisture - Genetics ● Structural genes ● Regulatory genes ● Operator genes Growing Season - Light frost vs. killing frost - Cool season vs. warm season - Hardiness zones Flowering - Physical aspects ● - Theories ● Nutrition as proposed by E. J. Kraus & H. R. Kraybill in 1918 ○ Carbohydrate - Nitrogen relationships ○ Amount in nitrogen influences flowering ● Hormonal regulation proposed by - Day lengths: ● Short day plants ○ Strawberries ● Long day plants ○ Spinach ● Day-neutral plants ○ Tomatoes ● Can have different types in the same species 670 nm Red; 730 nm Far-red (associated with dusk) Landscape Horticulture - Landscape architecture - Landscape design - create designs - Landscape contracting - puts in designs - Landscape plants - grow the plants that are put in by contractors ● Woody plant material Landscape design process - Site analysis or plot plant - need to know size of land and features of property ● Hardscapes - non living things (sidewalks, patio) ● Softscapes - living things (plant materials, beds) ● Utility lines ● Views that you may want to maintain or screen ● Easement - legal right to go on property that is not yours (for utilities and stuff) - Requirements of the homeowner/checklist ● Favorite plants ● Do they want an area for a grill, a pool, other water features - Area layout plan ● Areas that are in public view ● Private areas ● Service areas - areas that might want to be shielded from view of public and/or homeowner ○ trash cans, woodpiles, dog runs, compost piles - Structural plan ● Structural features ○ basketball hoop, koi pond, cluster of shrubs ● Elements of design/structural elements: ○ Lines of design communicate tone ■ Straight sidewalks to move you along vs. winding sidewalks for leisure ○ Form of features communicate formal, informal, freeform ○ Texture of plants to rocks, patio ○ Pattern ■ Patterns of mowed grass on sports fields ■ How bricks are laid out to give more interest ○ Color ■ emotion/tone invoked by color ● Techniques of design ○ Balance - equilibrium on left and right ○ Proportion - sense that size fits into the overall landscape ■ Designed for children or adults? ○ Scale - size choices that are suitable for setting ■ Colorado blue spruce would be too big next to a ranch home ○ Contrast - use of distinct differences to make the landscape interesting and attractive ○ Dominance - repetition of specific characteristics (rectangular spaces) with one exhibiting dominance ○ Rhythm - repetition of elements in regular measures in order to direct the eye - Planting plan ● Specific shrubs, bulbs, trees, turf etc. that will be grown - Final plan ● All of the other elements put together ● Placement of plants Use of plant material in Landscaping ● Functional uses ○ Screening ○ Shading ○ Wind diversion/insulating to reduce heating ○ Framing house or view ● Aesthetics (Take into account different qualities in different seasons) ○ Form ○ Texture ○ Color ● Plant types ○ Trees ○ Shrubs ○ Vine/lianas ○ Ground covers ○ Herbaceous perennials ○ Annuals 10/10/16 Plant Growth Regulators - Plant hormones vs. growth regulators - Auxins and auxin-like compounds ● IAA - indole acetic acid ● NAA - naphthalene acetic acid ● IBA - indoleacetic acid ● 2,4-D - 2,4-dichlorophenol Auxins - Cell enlargement and elongation - Photo- and geotropism - Apical dominance - Abscission of plant parts - Flower initiation and development - Root initiation - Fruit set and growth - Cambial activity - Tuber and bulb formation - Seed germination Horticulture usage of growth regulators - Rooting - Weed control - primarily 2,4-D - Fruit thinning - NAA only - Inhibitions of stem sprouting - Tissue culture Gibberellic Acid - Stem growth - Cell division and elongation - Enzyme secretion - Associated with flower initiation and sex expression ● Fruit initiation and growth ● Senescence ● Dormancy influenced by GA Cytokinins - Zeatin - natural one - Kinetin - BAP - 6-benzyladenine - Thidiaz… - Promotes cell division - Cell enlargement - Tissue differentiation (combination with auxins) - Dormancy - Phases of flowering and fruiting - Delay of leaf senescence - Found in embryos, germinating seeds and young developing fruit Commercial activities - Primary use is in micropropagation systems ● Stimulate axillary branching ● Stimulate development of buds in calli ● Use in overcoming apical dominance and stimulate lateral bud development Commercial Applications - Fruit ripening - Flower initiation - Changing sex expression-more females - Degreening ,.... - Shoot proliferation in tissue culture: high cytokinin and auxin level promotes shoot growth. Abscisic acid (ABA) - Biologically it has 2 functions: 1. Regulate processes in seed development 2. Initiate responses to cold and water stress - Major hormone implicated in stress tolerance and limiting growth ● Promotes embryo maturation ● Inhibits germination….. Others - Brassinolides ● Steroids - cell division and elongation - Salicylic Acid ● Activates pathogen genes - Jasmonates ● Defense against herbivores - Systemin ● Defense genes against herbivores Auxins - Cell enlargement, role in apical dominance Gibberellins - Cell (internode) elongation, seed germination Cytokinins - Cell division, delays senescence Abscisic Acid - Promotes dormancy, stomatal regulation E - Fruit ripening, senescence, Floriculture - The study of the growing, marketing, and arranging of flowers and foliage plants - Areas within floriculture: ● Cut flowers ● Potted plants ● Foliage plants ● Bedding plants - US department of commerce ● 19.4 billion in 2005, includes farmgate and retail sales - Global scale ● 90 billion in 2005, excludes retail sales - Nursery and greenhouse crops - 7.3% of total agriculture - 78% of all floral consumers are women - 41% of all floral consumers are over 55 - General information ● Greenhouses ○ Glass ones last the longest ○ Used since Roman times ○ Pit houses ○ Cold frames ○ Hotbeds - Trends in Floriculture ● Drop in production with some turnaround with mass marketing ● Cut flowers produced in other countries ● Increase in diversity of plants grown ● Foliage industry -- design and maintenance ● Double poly houses ● Use of hydroponics ● Aquaponics - Cut flowers ● Mums - chrysanthemums x morifolium ● Exhibition (dendranthema) ● Garden Roses - Rosa sp - Rosa Manetti - used for rootstocks - Major cut flower other than mums - 59-62 degrees F at night Carnations - Dianthus caryophyllus - America used to produce a lot of carnations, but not anymore ● Colorado - high light intensity, good for producing carnations - Grown 3-4 years before being harvested - Caging - keep carnations plants upright - Standards - single flower at the tip of a long stem (pinched lateral buds) - Sprays - pinched terminal bud to encourage lateral buds - 100s of cultivars Peruvian Lily - Alstroemeria aurea - Rhizomes - underground rhizome that generates new lateral rhizomes - From south america - Grown/used by Incas Gladioli - Gladiolus x hortulanus - Hybrid of multiple plants - Produced outside in fields - Transported upright so petals aren’t bent - Corms Orchids - Pseudobulbs or tissue propagated Snapdragons - Shipped upright, so tips don’t curl up Potted Plants Mums - Short day plants - Propagated by cuttings, pinched once or twice Poinsettia - Euphorbia pulcherrima - Short day plants - Cold sensitive, tropical Azaleas - R - Needs vernalization to flower - Takes 18 months-2 years to produce flowering Azalea Geranium - Pelargonium x hortorum - Clonal - Seed Easter Lilies - Lilium longiflorum - Bulb - Vernalization - Continue lighting to keep flowers - Remove anthers - Bedding Plants Petunia - Petunia x hybrida Marigold - Tagetes x hybridus - French - African American - Triploid - flowers last a long time, sterile, more robust plant Pansy - Viola tricolor x wittrockiana - Used to be number one bedding flower - Fell out of favor because they don’t do well in the hottest part of the summer - Now sold in the fall - Seed propagated Photosynthesis and Respiration - Metabolic process that involves synthesis or breakdown of biochemical compounds in plants - Photosynthesis produces chemical energy from the sun - Respiration breaks down sugars and releases stored energy Light Saturation and Compensation points Photosynthesis Pathway - Pigment, chlorophyll, captures ligth energy 6CO2 +12H2O → C6H12O6+6H2O+6O2 - Hill reaction (light phase) ● Occurs only in presence of light where light energy is passed via Chlorophyll electrons through the electron transport system to generate ATP + NADPH ● Photosynthesis - break apart 12H2O → 24H+ + 24e- + 6O2 - Electrons from water replace chlorophyll electrons ● Reduces NADP - NADPH - Photophosphorylation - the production of ATP by the addition of phosphate group to ADP using energy of light-excited electrons produced in the light reactions of photosynthesis - Dark reaction calvin-Benson cycle ● Chemical synthesis using NADPH and ATP from light reaction to generate sugar ● Captures carbon dioxide - C3, C4, CAM plants ● C3 plants ○ Fix carbon dioxide via Calvin-Benson pathway of photosynthesis ○ Fairly low to moderate rate of centimeter per hour ● C4 plants ○ Fix carbon dioxide via Hatch-Slack pathway ○ Produces more photosynthate per hour ○ Much faster rate ● CAM plants ○ Primary succulents found in dry desert areas ○ Stomates are closed during day and open at night ○ Modified C pathway ○ Slowest rate ○ Get CO2 from organic acids Carbon dioxide fixation pathways for C3 and C4 plants Respiration - The series of chemical reactions in which one molecule of glucose is broken down and converted to other chemicals which results in the production of many molecules of ATP ● Glycolysis ● Photorespiration - occurs in presence of light ○ C3 plants ○ Does not lead to ATP production ● Dark respiration ○ Occurs regardless of light in mitochondria ○ Drives the system Mitochondria - Respiration occurs here - Three steps: ● Glycolysis - in cytoplasm ○ Splits one 6-carbon into two 3-carbon pyruvic acids ○ Produces 2 ATP (directly), NADH ● TCA (tricarboxylic acid cycle) Krebs/citric acid cycle ○ First product is citric acid ○ Pyruvic acid acceptor, oxaloacetic acid ○ Produces 8 NADH, 2 FADH ● Electron transport chain ○ Takes 2 NADH from glycolysis, 8 NADH from Kreb’s cycle, and 2 FADH from Kreb’s cycle ○ Strips off their H electrons and uses them to produce 3 ATP’s per NADH and 2 ATP’s per FADH ○ Oxygen is the final electron acceptor ○ In the absence of O2, certain cells can switch anaerobic respiration and produce alcohol and a lot less ATP Absorption and Translocation - Movement of materials, organic or inorganic, from one area to another - Osmosis - diffusion through a semipermeable membrane from a region of higher concentration to one of lower concentration - Diffusion - the spread of particles from a region of high concentration to an area of low concentration - Active transport - movement of materials against the gradient, which requires energy Transpiration stream - Flow of water through through a plant from roots to leaves, via the xylem vessels Water potential - Cells with higher water potential will draw water to them Root Hairs - Extension of epidermal layers, water taken in from soil from ● High concentration ● By osmosis ○ Mycorrhiza ○ Fungus ○ Uptake of water and minerals - Theory of how water gets from roots to leaves ● There is no interruptions in stream of water in xylem ● Water molecules adhere by COHESION ● Strong force - Pressure from top pulling ● Dixon-Jolly cohesion-tension theory (transpiration stream) ● Evaporations of water out of leaves causes pulling of water through plant (apple uses 10-20 qts of water per day released through evaporation) Mineral transport - Minerals carried with water and by active transport system - Carrier hypothesis ● Energy to move minerals outside plant to inside Movement of Sugars - Translocation - transportation of food throughout a plant - Sugar from mesophyll cells - Pressure - flow hypothesis - Sugar unloading
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