Horticulture Exam 3 Penn State

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what is a rhizome what is one example of a plant with a rhizome and how would you propagate it?

-A rhizome is an underground stem that grows horizontally/ just below soil surface. Can be categorized into two types: the thick, fleshy, compressed structure typified by the iris, and the slender, elongated underground stems of lily-of-the-valley. -B/c they are stems, rhizomes have nodes and buds along their length; new plants can arise at these nodes. Other examples of rhizomatous plants include bamboo, sugarcane, and many grasses.

what are 3 advantages and 3 disadvantages of propagating plants by seed?

-Advantages: Increases genetic variation forming hybrids with superior qualities Highly nutritious( yum) Used to propagate majority of crop plants Can be stored for varying lengths of times following harvest -Disadvantages: Due to genetic variation, very difficult to retain superior qualities Trees may take more time to produce seeds than grafted plants Crop production area do not provide best conditions for high quality disease free seeds

How do plants with sexual incompatibility prevent selfing?

-Sexual Incompatibility: genetic trait in which pollen fails to grow down the style of does not germinate on the stigma of a plant with the same incompatibility alleles. -plants with SI have greater chance for genetic diversity. The plant prevents itself physiologically from selfing. Pollen tube could be malformed or something like that. what u put was right

what are tuberous roots and stems list one example of a plant with a tuberous root and one example of a plant with a tuberous root stem how would you propagate each

-Tuberous Roots are enlarged secondary roots; because they are root tissue, not stem tissue, there are no nodes or buds. Examples of plants with tuberous roots are sweet potato and dahlia. Tuberous roots act as storage structures, allowing the plant to survive a dormant period. In the spring, the new, adventitious shoot growth utilizes the food stored in the roots, and the root shrinks and eventually disintegrates. The plant produces new tuberous roots each season. -Tuberous Stems are swollen sections of stem; however, unlike tubers, they don't occur at the tips of underground stems. Rather, they occur on the main stem, often just below the soil level. Tuberous stems generally have a vertical orientation with vegetative buds produced on the upper end (the crown), and roots at the basal end. Examples include tuberous begonias and cyclamen. Unlike tuberous roots, tuberous stems are perennial, and continue to enlarge every year. With begonias, for example, you can dig up the "tubers", store them, and replant them year after year.

What is an offset how is this used in propagation

-an offset is a small, virtually complete daughter plant that has been naturally and asexually produced on the mother plant. They are clones, meaning that they are genetically identical to the mother plant. - In the plant nursery business and gardens, they are detached and grown on in order to produce new plants. This is a cheap and simple process for those plants that readily produce offsets as it does not usually require specialist materials and equipment.

Describe the process you would use to test a "lot" of collected wildflower seed. What are 3 characteristics would you report.

1. Germination 2. Vigor 3. Noxious weed seed contamination

What are the 3 main requirements for seed germination?

Correct Water amount for imbibition, correct Oxygen amount for aerobic respiration, correct Temperature for germination

Describe a seed that would be suitable for use with an automatic seeder? What would you do with a seed that did not have these characteristics to allow an automatic seeder to be used.

A seed with strong enough seed coat to resist being knocked around in the seeder, a similar size and shape seen amongst all seeds - Cover the seed with a protective coating that works much like a seed coat gives general same size and shape to all the seeds, that is removed when coming into contact with water or through the imbibition phase of germination

how do you propagate a hyacinth

As your hyacinth plant grows, you will notice that younger offset bulbs develop at the base of the plant's main bulb. You can actually use these younger bulbs not just for the propagation of the plant, but for developing new cultivars that can produce fancy flowers later on. You will need a good number of offset bulbs to effectively cultivate hyacinths. For this, you can use a technique called scoring to tremendously enhance the growth of offset bulbs in a hyacinth plant. To score the main bulb in a hyacinth plant, make two to four cuts through the basal plate. Within approximately three months, new offset bulbs will develop around the area where the cuts were made. These new bulbs can now be used to propagate new hyacinth plants. One technique you can use involves re-planting the parent bulb along with the new bulbs into a deeper pan. Just allow the offset bulbs to mature for a few weeks. When replanting, make sure that the younger offset bulbs are covered by thin layer of compost. In a few months, the new bulbs will sprout and grow while the parent bulb slowly decays, leaving you with several younger hyacinth plants.

Define apomixis and give an example of why apomixis is important to the horticulture industry.

Asexual Reproduction in plants. It is important to help keep purebreds pure and it can help future generations of plants to be resistant to pests and diseases

You are considering the establishment of a small business producing seedlings of native trees and shrubs of eastern Pennsylvania. You have a limited budget so must develop an operation which will require a limited amount of construction, equipment, and other resources in order to get started. (1) What would be your primary needs or the minimum requirements to start this business? (2) What would be your source of seed?

Best sources of seed: Natural, found in the woods or fields, or buying in bulk. Primary needs: A greenhouse. Water. Fertilizer. Soil. Pots. Time. Correct market. Fans. And tags to know what all is what.

Why are some seeds coated with fungicides? Why not coat all seeds?

Certain species have fungicide treatments on their seed to prevent disease problems that may inhibit the plant from establishing. A lot of agronomic crop seeds are coated with fungicide to prevent things like damping off or other fungal problems & to ensure a uniform establishment. This is sort of expensive and definitely not necessary for most non-agronomic species.

List and briefly describe 3 natural methods plants "use" to encourage outcrossing.

Dioecy: dioecious plants have pistillate( female) and staminate( male) flowers present in separate plants such as asparagus and pistachio. Female only flowers= gynoecious. Male only flowers = androecious. This flower arrangement forces cross pollination. Monoecy: plant trait in which the male and female parts are in different flowers but on the same plant. Examples: corn, walnut, oak Dichogamy: genetic trait in which male and female flowers on the same plant bloom at different times

What is secondary dormancy? Provide an example of environmental conditions which could induce secondary dormancy?

Dormancy induced in seeds capable of germinating immediately after ripening by the presence of one or more conditions unfavorable to germination, Photodormancy which occurs in seeds that are inhibited by light when they are exposed to an excess of light

How would you prepare a bed for direct seeding of pine seedlings?

Each pine tree seedling should have plenty of space and no root systems of other plants nearby, choose a well-drained area of soil, mulch often

What is F1 hybrid seed? Describe the process used by a plant breeder or seed producer in producing F1 hybrid seed.

F1 Hybrids:first generation of a planned cross. They result from the cross between seedling populations of two or more inbred lines. the result is a population of uniform but heterozygous plants. Often these populations exhibit greater vigor than parents due to hybrid vigor(heterosis)

You wish to germinate a seed, which has a double dormancy (an embryo dormancy requiring a period of cold stratification and a hard seed coat preventing water uptake). Describe in proper sequence the procedures and conditions required for breaking this dormancy and getting the seed to germinate.

For this, you must break or scratch the seed into a certain level, at that point, the seed should be wetted and planted so it can germinate behind the double seed dormancy.

Describe the process of priming seed? What are the advantages of using primed seed? The disadvantages?

Form of seed preparation in which the seeds are pre-soaked before planting for a pre-determined time interval and halted before first root or radicle emerges from the seed -Advantages - helps in arid countries to overcome soil deficiencies and improve crop rotation, can store primed seeds for later use -Disadvantages - difficult to store sometimes needing cool temperatures, process is time consuming

Which flower parts give rise to: the fruit, the seed, the embryo, the endosperm, and the seed coat or coverings?

Fruit- Matured Ovary Seed- Ovule Embryo- egg cell fusing with 1 generative nucleus Endosperm- polar nuclei & generative nucleus Seed coat- integuments

Describe how the plant growth hormones, gibberellin, ABA, and cytokinin influence dormancy.

High ABA and low GA characterize dormancy in the embryo, for germination to occur ABA must be low and GA must be higher, ABA low embryo growth potential, GA increases embryo growth potential by weakening the seed coat so the radical of the seedling can break through the seed, Cytokinins influence cell division and shoot formation, can be used to overcome dormancy

Describe what is taking place in each of the three stages of a developing seed from the time of fertilization.

Histodifferentiation- The first stage when the seed begins to grow. Auxin form and the roots also begin to emerge. Cell Expansion- When the cell expands due to growth in and outside the soil. Maturation drying-Vascular connection with the mother plant is broken. Seed begins to lose water. Seed is quiescent following drying.

There are three stages in seed development. Histodifferentiation; Cell expansion; and Ripening and drying. Describe the major processes occurring during each stage.

Histodifferentiation: differentiation of the embryo and endosperm mostly due to cell division and embryo reaches the beginning of embryogenesis Cell Expansion: rapid cell enlargement- often called seed filling- due to accumulation of food reserves. Active period with large increases in RNA, DNA and protein synthesis Mature Drying: physiological maturity occurs prior to mature drying where seed has reached max dry weight through reserve accumulation→ stage when seeds can be removed from fruit and show high germination potential. Drying defined by rapid water loss. Water loss occurs from seed coat and natural openings at hilum( scar left from funiculus detach). funiculus= vascular connection to mother plant.

What is the difference between a cultivar obtained through selection and one obtained through hybridization?

Hybridization is a cross between two genetically different parent plants to produce an offspring while selection is producing progenies of a superior line

You are going to be an astronaut on the first Mars mission. It will be far too costly to carry all the food needed for the entire trip with you so part of the mission plan is to supplement the food supply by growing much of the food (60% or more) needed, both while on the planet, and for the return trip, in a production facility you will set up on Mars. You have the responsibility of managing the crop production facility on Mars. You have the choice of superior F1 hybrid cultivars or so-called heirloom varieties obtained from seed banks and "third world" farming communities. Which will you choose and why? Provide at least two reasons for your choice and explain why your choice is superior to the alternative for each. (Consider that cargo weight will be severely restricted on the outbound trip, the transit time on the way back will be about 9 months and you will be on the planet for about 1 year).

I would bring the heirloom varieties. F1 hybrids are a cross between two unique individuals and will yield you good quality, uniform fruit. When you cross the F1 lines, however, the result is not uniform and undesirable. The heirloom seeds can be harvested from the fruit and grown again. Heirloom varieties are also not uniform, but they yield a lot of fruit. Using heirloom would reduce the amount of seed you need to carry to Mars. Plus, heirloom varieties definitely taste better in most crops.

describe the process of crown division list 5 plants you might propagate this way and the time of year you would divide each

If you want a healthy root system, divide spring-blooming perennials after flowering and fall-blooming perennials early in the year. This timing allows the plant to concentrate the energy to the root system so the plant gets a solid start in the new site. Dividing the crowns starts by digging up the plant. Locate the outer edges of the root ball by digging a shallow trench on the outer perimeter of the foliage. This allows you to locate which direction the roots are growing and how big the root system really is in comparison to the plant. A pair of garden forks make quick work of lifting a large intact root ball from the site. Slide one garden fork along one side and under the root ball and the other garden fork along side and under the other side of the roots. With a gentle prying motion, slowly lift the root ball from the planting site. You can see the entire root system when you spray the roots with a garden hose set at a gentle mist. Once you have the root ball lifted and sprayed clean, you have two choices for dividing the crown -- use your hands to pull the roots apart or cut them with a sharp knife. Each divided section of the plant must have at least one bud for the plant to grow new foliage. chrysanthemum, day lily, peony, iris and aster are suitable for this propagation method

what is a contractile root what is its function

In most cases, contractile roots not only produce a strong pulling force on but also push away thesubstratum and create a soil channel in which plant movement is made easier.

What is the difference between a "landrace‟ and a "hybrid‟ seed? What is an advantage and a disadvantage of cross-pollination compared to self-pollinating crops to the producer of horticultural crops?

Landacre: selected portions of a crop which have been saved and used to produce in the next cycle. Results in genetic populations adapted to a localized environment. Provides buffer against environmental catastrophe. Preserves genetic diversity. Hybrid Seeds: population that is produced by cross-pollinating two or more parental lines. Advantage of Cross Pollination: enhanced plant vigor, increased heterozygosity promoting evolutionary adaptations Disadvantages of Cross Pollination: increase in potential for undesirable mutations, more disease Advantages of Self Pollinating: reduced level of plant resource for seed production Disadvantages of Self Pollination: restricts genetic diversity

You are a bedding plant grower. You ordered too much and thus have geranium seed left over this year. Describe how you would store this seed to use it next year. How would you change your process if you had to store it for 5 years?

Lay a clean piece of paper towel on a small plate. Geranium seeds are tiny, a plate with edges prevents them from rolling and falling. Place the geranium seeds on the paper towel and let them sit in the sun for 24 hours in an area protected from wind to dry out completely. Never store wet seeds. Carefully pick up the paper and bend the sides to create a funnel. Pour the geranium seeds into a small and dry canning jar. The canning jar should be airtight. Tightly close the jar and place it in a refrigerator. Chances are these seeds will not be able to be stored for that long and still be viable

what is the most common commercial method of propagation for a daffodil

Micropropagation methods are not used for commercial production but is used for establishing commercial stock.

What is an orthodox seed? How would you store, pack and ship orthodox seed for commercial propagation or distribution? How does this differ for recalcitrant seed?

Most annual crops are orthodox. This means that the seed can withstand very low levels of moisture and can tolerate drying around 5% & low temperature. So for ' shipping, you would want to pack the seeds in a cool, dark place with low moisture levels. A recalcitrant seed is one that is sensitive to drying and can not withstand moisture content below 12-30% depending on the seed type. They are also sensitive to low temperatures.

How would you harvest seed of a plant like tomato?

Once the fruit is fully ripen, you can scoop out the seeds (along with the gunk surrounding then) from the fruit. Place in a jar with some water and wait a few days until the seeds sink to the bottom. Then you can pour out the liquid and collect the seeds before drying them in a paper towel. Store in a cool, dry place.

What is parthenocarpy? Describe the importance of parthenocarpy to commercial horticulture using at least one example.

Parthenocarpy: the formation of fruit without seeds Important because the number of seeds within a fruit strongly affects the fruit size in species like apples and strawberries. Commercial Horticulture Example: greenhouse cucumber fruit development because there are no reliable insect pollinators in the greenhouse

You wish to propagate a seed that has both a (1) physical dormancy, due to a hard seed coat and (2) an immature embryo. Describe the procedures, in proper sequence that you will need to take to germinate this seed.

Physical dormancy( Exogenous), due to a hard seed coat is broken with scarification Immature Embryo( Endogenous): embryo lacks growth potential to penetrate seed covering. Dormancy can be broken by weakening seed coverings

What does the provenance of collected woody plant seed refer to? Why would you, a commercial nursery propagator in Pennsylvania care?

Provenance refers to where the plant, from which you selected seed, was grown. A propagator would want to know this to understand what environmental conditions the plant was growing in. Depending on where a plant is grown, it may show vast differences in phenotype, performance, etc.

what is the function of the seed coat or other seed coverings give one example of how the seed coat influences commercial seed propagation practices

Seed Coat: Also termed Testa is derived from ovule. Protects the seed from physical, temperature related, or water-damage. Provides mechanical protection for the embryo, making it possible to handle seeds without injury, and thus permitting transportation for long distances and storage for long periods of time.

Describe the process of seed priming and its relationship to the three phases of seed germination. You may use a labeled diagram to aid in your answer. Also, list two advantages and two disadvantages of priming seeds?

Seed Priming: Controlled seed-hydration treatment that can reduce the time it takes for seedlings emerge Advantages: primed seeds show higher seed vigor than raw seeds. Faster more uniform seedling emergence for field and greenhouse crop Disadvantages: additional cost. Must be stored in a cool temperature. As seeds deteriorate the 1)lose vigor 2)capacity for normal germination 3)viability

Define imbibitions. How does medium matric or osmotic potential influence imbibitions? How is this relationship used in commercial propagation?

Special type of diffusion when water is absorbed by solids-colloids causing an increase in volume and for germination to break the seed coat for the emerging radicle

describe the scaling of a Lily

Step #1. Start with fresh-harvested, locally grown bulbs. The lily's reproductive cells need to be on a natural cycle for best vitality. Do not use cheaply obtained lily bulbs, either in spring or September, from questionable sources. These usually are bulbs that were left unsold from the greenhouse forcing market and have been unnaturally stored in freezers for over a year. Dehydration from long storage will cause their growth to be marginal when compared to fresh bulbs. Best results are from lily bulbs fresh from the garden, scaled in October, with the new bulblets planted outdoors in March. Step #2. To begin, remove all of the outer two rings of scales and discard. Carefully break off the remaining layers of bulbs, completely down to the "pit" - the center of the bulb, where the shoot emerges. Step #3. Set out the "scales" and the "pit" to dry overnight. DO NOT wash the scales to "clean them," or you risk contamination. They will air-dry and the broken surface will callous, naturally protecting the scales from fungus. The next day you may replant the lily bulb core. It will put up a pathetic-looking stem the first year, but should recover the following season with a bloom or two. Step #4. Place scales between layers of slightly damp vermiculite or peat (sterilized) in a plastic bag that is loosely folded at the top. Place in a warm, evenly heated location of about 70?F. for 8 to 10 weeks. Do not allow any lily scales to come in direct contact with the plastic bag. If water droplets form on the plastic, there is too much moisture - open the bag immediately to allow in more air. Step #5. When bulblets are about the size of green peas or shelled filberts (their growth depending on the type of lily) they are moved into cold storage for their first "winter." After six to eight weeks of temperatures just above freezing, the bulblets are ready to be planted either outdoors or in a greenhouse. Step #6. Scatter in weed-free, perfectly drained ground, covering the bulblets with only one inch of soil. Keep bulblets evenly moist the first summer, checking soil moisture before irrigation. Do not allow the soil to completely dry, or all growth will stop for the summer. Most cultivars will send up tiny stems from 4 to 12 inches in height, depending on the Lilium type. Step #7. These yearlings may be harvested and moved to a permanent location in October. Most will have one or two flowers the second year, but Asiatics require an additional two years of growth and Orientals, three years, before they are of commercial size.

how can you propagate a tulip

The commonest form of commercial propagation is by twin-scaling, in which the bulbs are cut into many small pieces but with two scales still connected by a small fragment of the basal plate. The fragments are disinfected and placed on nutrient media. Some 25-35 new plants can be produced from a single bulb after four years.

define Bulb

The definition of a bulb is any plant that stores its complete life cycle in an underground storage structure.

What is DNA fingerprinting? Explain how you might use it in seed production or propagation.

This is a test that separates fragments of DNA to determine genetic purity. It is really accurate and can identify a large number of plant cultivars. This allows seed producers and breeders to differentiate lines that are only slightly different.

What is endosperm? Why is endosperm important in some seeds?

The major storage tissue in seeds. It is derived from the haploid female gametophyte in gymnosperms( naked seeds), while in angiosperms( flowering plants) it is the result of gamete fusion that forms a triploid( 3n) storage tissue

what is a corm what is 1 example of a plant with a corm how would you propagate your example

a rounded underground storage organ present in plants such as crocuses, gladioli, and cyclamens, consisting of a swollen stem base covered with scale leaves. Ex. Water Chestnut Corms are similar to bulbs but do not have fleshy scales. Corms are either rounded or slightly flattened at the top and have dry scale-like scales held together at the basal plate where the roots grow. The parent corm dies back but produces cormels or cormlets from buds on the top or side of the original corm. Large new corms may flower the following year, but the smaller cormels may take several years to bloom. Cormels can be divided from the shriveled parent corm and planted separately. Gladiolus and crocus are examples of corm plants.

what is the difference between a tunicate and a nontunicate bulb

There are two types of bulbs - Tunicate or Non-tunicate. Tunicate bulbs have a papery (tunic) covering and solid bulb scales. Nontunicate bulbs have no tunic covering and the bulb scales are loose.

Describe how you would determine the optimum temperature for germination of a "lot" of conifer seed collected from a squirrel cache in Southern PA? You have another lot of seed collected in Northern Vermont. Would you expect the optimum to be the same? Why or why not?

Through an experiment that the only variable is temperature, test 100 of these seeds through a range of temperatures and mark which ones had most success -Temperature is one of the main parts of seed germination, the optimum temperature might not be the same due different species and different climates, also the success for seed germination might be different from two different places based on the other two factors of germination Water and Oxygen

How would you harvest seed of a plant like impatiens?

Wait until you see spent flowers, a seed pod should be forming at the base of each flower. There are tons of little seeds inside of this pod so place it inside a bowl or envelope to collect them. It may mature & open on its own or you may need to gently split it by hand. Store seeds in a cool, dry place.

What are the 3 stages of seed germination? How does seedling fresh weight change during each stage? used in commercial propagation?

tep 1-Water imbibition results in rupture of seed coat, uniform imbibition is important and approximately optimum temperatures are required Step 2-The imbibition of the seed coat results in emergence of the radicle and the plumule, the cotyledons get unfolded. It is important that the temperature and photo period are required in optimum amounts Step 3-This marks the final step in the germination of the seed where the cotyledons are expanded which are the true leaves

what is a tuber what is 1 example of a plant with a tuber how would you propagate your example

your example plant? a much thickened underground part of a stem or rhizome. Potato Research has shown that a seed piece this size has the adequate amount of carbohydrates levels for shoot initiation and growth. If the tubers are cut, the usual procedure is to let the cut pieces to suberize or cure, for about 10 days. Suberization in tubers allows them to develop a corky layer around the seed piece that prevents the seed piece decay by the entrance of several kinds of pathogens.