Propagation Lab Quiz
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Created by:
robwinfield Plus on February 13, 2012
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English | Math / Symbols |
|---|---|
 3 types of fruit | 1. Non-dehiscent dry fruit 2 Dehiscent dry fruit. 3. . Fleshy fruit. |
| What organs must be formed adventitiously in leaf cuttings? | roots and shoots |
| 3 methods of seed stratification | The first method involves the storage of presoaked seed in a moisture-retaining medium inside a refrigerator. The second approach involves the storage of seed outdoors in pits or raised beds enclosed in wooden frames. The last method of stratification is the direct planting of dormant seed outdoors thus allowing natural environmental conditions to promote after-ripening. The optimum time of sowing is a species-specific requirement which reflects the natural conditions under which the plant is normally found |
| definition of dehiscence | Dehiscence is the opening, at maturity, in a pre-defined way, of a plant structure, most commonly fruits, anthers and sporangia, to release its contents. Sometimes this involves the complete detachment of a part. Structures that open in this way are said to be dehiscent. Structures that do not open in this way are called indehiscent, and rely on other mechanisms such as decay or predation to release the contents. |
| Do roots or shoots form most quickly on leaf cuttings? | roots |
| how does propagation of leaf cuttings differ from leaf-bud cuttings | leaf cuttings produce roots and shoots, leaf-bud cuttings roots only |
| Which seed stratification treatment should work best, the cold treatment or the root temperature treatment? | The cold treatment, seed stratification requires 35° to 45° F |
| What is the ecological advantage to seeds in stratification? | THe seeds dont' sprout in the autumn and die in the winter cold, they require a cold dormancy and then they come up when it warms up in teh spring |
| What two types of dormancy need stratification for germination to occur | Morphological and Physiological dormancy |
| What 4 conditions for successful stratification? | 1. 35° to 45° temperature 2. Aeration 3. Moisture 4. Time -- 1-4 months |
| What is the difference between a plant hormone and a plant growth regulator? | Plant hormone is naturally occurring plant growth regulator is man made |
| what is the naturally occurring auxin and 2 synthetic auxins? Give full chemical name and appropriate abbreviation for each | IAA Indole acetic acid (natural) IBA Indole 3 butyric acid KIBA Indole 3 butyric acid potassium salt |
| Why use synthetic auxins instead of IAA? | because synthetic auxins don't break down as quickly when applied to living tissue |
| 2 undesirable outcomes of too much auxin | callouses and necrosis |
| 3 positive effects of auxin-containing rooting compound on a cutting? | 1. Great percentage of cuttings develop roots 2. Develop roots faster 3. More and longer roots |
| How to collect seed from non-dehiscent dry fruit? | Pods, capsules, cones, siliques, etc. Must collect before seed is released (dehiscent) Collect as fruit changes from green to tan/brown Dry fruits fruits- canvas canvas tray screens paper bag , tray, screens, paper bag Extract seed from fruit - flail, beat, roll Clean/separate seed from fruit - air blast, gravity gravity screening |
| How to collect seed from fleshy fruit? | 11 Maceration . Maceration -crush fruits -mix with water 22 Fermentation . Fermentation -macerated fruit & water sit in vats -2-4 days, room temp, stirring 3. Cleaning/separation -screens to rub fruit through -floatation floatation (pulp & bad seeds float; (pulp & bad seeds float; sound seed sinks) |
| Storage of seeds -- temp and humidity levels | Moisture content - 4-6% is ideal - should be non-fluctuating Temperature - for many seed 0°F is ideal - Others prefer temperatures 35-40°F |
| are beans dehiscent or non-dehiscent? | non-dehiscent -- they don't open up |
| With leaf cuttings, how are roots and shoots formed? | Adventitiously |
| What forms first, roots or shoots? | roots |
| Define totipotency | - ability of all living cells potentially to regenerate whole new individuals (DNA info is there!) |
| Define dedifferentiation | Dedifferentiation - loss of specialized form or function of cells |
| Differentiation of cells | Differentiation - cells or tissues undergo a change toward a more specialized form or function |
| What part of the plant is a leaf cutting? | Either part of the leaf or the whole leaf? |
| Leaf-petiole? | leaf blade plus petiole |
| Leaf-bud cutting | whole leaf and petiole, plus axillary bud and piece of stem |
| What emerges from leaf cuttings? | adventitious roots and shoots |
| What emerges from Leaf Petiole cuttings? | adventitious roots and shoots |
| What emerges from Leaf Bud cuttings | adventitious roots only |
| 7 factors to consider with leaf cuttings | 1. Limited number of species by this method 2. Efficient - lots lots of new plants from single stock plant of new plants from single stock plant 3. Typically a slow process 4. Original leaf not part of new plant 5. Sometimes don't get true-to-type plants back 6. Vasculature is important 7. Dry cuttings of succulent plants to close wound |
| How do you make and plant stem cuttings? | Usually 4-6" long •Stripped of foliage at base •Wounded, plus auxin applied •Maintain humidity around cuttings •Bottom heat |
| 5 features of hardwood stem cuttings | •Dormant, fully matured tissue •Late fall through mid-winter •Usually last seasons growth •Deciduous or evergreen (needle and broadleaf) •Long time to root |
| 3 features of semi-hardwood stem cuttings | Summer dormant, recently matured •August-November •Usually broadleaf evergreens (Ex. rhododendron) |
| 4 features of softwood stem cuttings | •New growth, firm but not completely hardened off •Mostly deciduous plants •Roots quickly •Collect cuttings in early morning |
| 4 features of herbaceous stem cuttings | •Soft tissue from non-woody species •Root very quickly •Low auxin conc. needed •Anytime of the year |
| What 3 things do you do to make stem cuttings, and what happens? | 1. Wound at cutting base 2. remove bark, phloem, cambium 3. 1 or 2 wounds per cutting 1. cell division is enhanced at wound 2. auxins, carbos accumulate @ wound 3. increases hormone uptake 4. creates a break in tough cell layers allowing roots to grow out |
| what is seed dormancy | when seed will not germinate even when provided proper germination environment |
| What is exogenous dormancy? | outside of embryo due to seed coat (allows nothing in or out; inhibitor chemicals) |
| What is endogenous dormancy? | 1) Morphological - embryo not fully developed 2) Physiological - embryo chemically inhibited |
| What are the ecological advantages of seed dormancy? | Permits germination only during times of favorable germination conditions |
| what is seed stratification? | - providing a period of cool, moist chilling 1) Seed must be imbibed (moist) 2) Aeration must be adequate 3) Chilling temperatures (32-45°F) 4) Certain period of time (1-4 months) |
| What are the benefits of auxin? | - providing a period of cool, moist chilling 1) Seed must be imbibed (moist) 2) Aeration must be adequate 3) Chilling temperatures (32-45°F) 4) Certain period of time (1-4 months) |
| What if you get too much auxin? | callous and necrosis |
| what if not enough auxin? | poor rooting or no rooting |
| 3 common auxins | IAA indole acetic acid (natural) IBA indole butyric acid NAA naphthaleneacetic acid |
| 4 auxin carriers | Talc Water Alcohol DMSO (dimethyl sulfoxide) |
| What auxin concentrations in ppm for which kinds of plants (herbaceous to hardwood)? | •Herbaceous none - 500 ppm •Softwood 1,000 ppm •Semi-hardwood 4,000 ppm •Hardwood 8,000-10,000 ppm |
| what concentrations are in Hormodin 1, 2 and 3? | Hormodin #1 1,000 ppm •Hormodin #2 3,000 ppm •Hormodin #3 8,000 ppm |
| In air layering is the stem removed from the mother plant? | no |
| What is the goal of air layering? | develop adventitious roots |
| 5 advantages of air layering | 1. Some plants naturally do it 2. For hard/slow to root species 3. Gets goodies from mother plant 4. Get large plants fast 5. Requires minimal facilities to carry out |
| 4 disadvantages of air layering | 1. Labor intensive 2. Relatively slow process 3. Takes up considerable space 4. Get relatively few new plants per stock plant |
| 4 scenarios where air layering is used | 1. When stems can't bend to ground 2. Bring rooting medium up to shoot 3. Reroot leggy plant 4. Large-leaved plants - where cuttings impractical |
| example where air layering is used | rubber tree |
| 3 requirements for air layering | 1. Girdling 2. Light exclusion 3. Add auxins to cut |
| what does girdling do? | Causes auxin, carbohydrates, rooting cofactors to accumulate Auxin moving basipetally |
| 3 types of Exogenous dormancy | physical mechanical chemical |
| What is physical dormancy and how is it broken? | Physical Dormancy, also called Seed Coat Dormancy, occurs when seed coats or coverings are impermeable to water. The degree of dormancy depends on species and environmental conditions during maturation and storage. This type of dormancy can preserve the seed for many years. Softening or scarifying the seed coat can induce germination. In nature, softening of the seed coat occurs by microorganisms in the soil during warm, moist periods, by the alternating freezing and thawing process, by fire, or by the passage through the digestive tracts of birds and mammals.Horticulturists can artificially scarify seeds with mechanical abrasion such as chipping the seed coat by rubbing with sandpaper, cutting with a file, or cracking with a hammer. Scarification can also be accomplished with acid soaks (sulfuric acid), hot water treatments (180°F), warm/moist treatments, high temperature (fire) treatments or by harvesting immature fruit. This type of dormancy is characteristic of Robinia spp.(Locust) and Acacia spp. |
| what is mechanical dormancy and how is it broken? | The seed covering prevents embryo expansion during the germination process. Generally this dormancy is not the sole nor primary cause of dormancy. To overcome mechanical dormancy, seed coat modification by the same procedures described for physical dormancies can be used. Examples include walnut, pits of stone fruits and stones of olives. |
| What is chemical dormancy and how is it broken? | Chemical Dormancy is caused by chemicals that accumulate in the fruit and seed-coverings during development and subsequently inhibit germination. "External" chemical inhibition originates in the fruit and seed covering and is overcome by prolonged leaching of the seeds with water or by removing the seed coat. By leaving the seeds under running water, the chemical inhibitors can be washed away. "Internal" chemical inhibition originates inside the seed. Examples are tomatoes, pears and grapes. |
| 2 types of Endogenous dormancy | Morphological and Physiological |
| What is morphological dormancy? | - a broad category of dormancy characterized by plants which do not have fully developed embryos at the time of fruit ripening/seed dissemination. Further embryo development is necessary after separation of the seed from the plant. A period of warm stratification helps to hasten seed germination with this type of dormancy because the underdeveloped embryos need to enlarge after the seeds have imbibed water but before germination begins. |
| 2 kinds of morphological dormancy | rudimentary embryos and linear or undeveloped embryos |
| Rudimentary embryos | - The proembryo is embedded in a mass of endosperm tissue at the time of fruit ripening; chemical germination inhibitors are present in the endosperm which become active with high temperatures. Examples include Ilex spp.(Holly) and Symphoricarpos spp.(Snowberry). Multiple dormancy mechanisms may be involved and dormancy is broken by: 1) exposure to temperatures < 59° 2) alternating temperatures 3) treatment with KNO3 or gibberellic acid |
| Linear or undeveloped embryos | This type of dormancy is due to partially developed embryos that require further growth prior to germination. Temperatures of approximately 68 F and/or gibberellic acid treatment favor germination. Some species require a cold chilling period after warm temperatures (Fraxinus spp.(Ash) and Euonymus spp.(Spindle Tree)). |
| What is physiological dormancy? | This internal dormancy is caused by factors originating within the living tissues of the seed. More than one dormancy mechanism appears to be involved at any given time. |
| Nondeep Physiological Dormancy | Nondeep Dormancy is the primary dormancy that exists in many of the freshly harvested seeds of herbaceous plants. This type of dormancy is often short-lived , disappears during dry storage, and is not usually a problem because the after-ripening is completed by the time the seeds are sowed Seeds that have a requirement for light or dark conditions are photodormant, and are included under the category of nondeep dormancy. Dry storage will often eliminate physiological dormancies with time. After-ripening, for germination is facilitated by short periods of chilling, alternating temperatures, treatments with potassium nitrate and gibberellic acid, and meeting photodormancy (sensitivity to light) requirements. |
| What is Intermediate Internal dormancy? | This is caused by seed covering and storage tissue. Examples of this type of dormancy include Pinus spp.(Pine) and Picea ssp. (Spruce). Chilling, or stratification, greatly accelerates germination. Embryo excision also overcomes dormancy. |
| Deep dormancy | Seeds with Deep Dormancy or Embryo Dormancy require long periods of cold stratification in order to germinate. Excised embryos will not germinate unless given a moist-chilling period of one to four months at temperatures of 35-45°F with adequate aeration. The 1 to 3 months of chilling should occur after the seeds have imbibed water; this is the reason the stratification process is also called moist-chilling by professionals. |
| epicotyl dormancy | Some seeds have separate dormancy conditions that need to be met for the radicle, hypocotyl, and epicotyl before germination occurs. Often, these types of species need a warm period of 1 to 3 months followed by chilling period of 1 to months, or a chilling period followed by a warm period and then another cold period. In nature, this can take 2 full growing seasons to germinate! |
| Double Dormancy | - Double dormancy includes any combination of exogenous and endogenous dormancy requirements that must be relieved sequentially to allow germination. This is also sometimes called Combinational Dormancy. To induce germination, all conditions must be met, and met in a proper sequence, for germination to occur. For example, seed coverings must first be modified to allow water entry. After this, a warm treatment followed by cold stratification is needed to cause after-ripening of the embryo. This type of dormancy is characteristic of tree and shrub species with hard seed coats but whose plants grow in cold winter areas. |
| secondary dormancy | While primary dormancy is an adaptation to control the time and conditions for seed germination, secondary dormancy is a further adaptation to prevent germination of an imbibed seed if other environmental conditions are not favorable. This dormancy occurs after the seed is separated from the plant. Dehydration and dry storage prevent secondary dormancy formation. This type of dormancy occurs in certain seed species when the environment does not permit germination and induces dormancy in seeds that were previously nondormant. These conditions can include unfavorable high or low temperatures, |
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