Horticulture Science - Pollination, Fertilization, Seedling Establishment

What is the approximate number of pollen grains produced per ovule in a typical apple flower, assuming 5 stigmas each with 2 ovules? A) 70,000 B) 3,500 C) 7,000 D) 250,000

C) 7,000. An apple flower with 20 anthers produces 70,000 pollen grains (20 * 3,500), and with 5 stigmas each having 2 ovules (10 ovules total), this averages to 7,000 pollen grains per ovule.

Which of the following is considered the first step in the overall process leading to fruit and seed production? A) Pollination B) Fertilization C) Flowering D) Anthesis

C) Flowering. The sources state that flowering is the first step, followed by pollination (2nd) and fertilization (3rd).

True or False: Seed development is triggered by fruit development.

False. The sources explicitly state that seed development triggers fruit development.

A plant that requires pollen from a different plant to achieve fertilization is known as an obligate ___.

Outcrosser. An obligate outcrosser is a plant that requires pollen from a different plant because its own pollen will not achieve fertilization due to self-incompatibility.

What is the recommended isolation distance for seed production in wind-pollinated crops like beet, corn, or spinach? A) 1/4 mile B) 1/2 mile C) 1 mile D) 5 miles

C) 1 mile. Wind-pollinated species like beet, corn, and spinach require 1 mile isolation for seed production.

Which of the following processes immediately follows pollen transfer to a stigma in the steps of pollination and fertilization? A) Anthesis B) Growth of germ tube to ovary C) Fertilization of ovule D) Pollen germination

D) Pollen germination.

The sequence of steps in pollination and fertilization is as follows:

•Anthesis (pollen shed)

•Pollination (pollen transfer to a stigma). This can occur within the same flower or plant (self-pollination, e.g., tomato, peach, pea) or between differing plants (cross-pollination, e.g., apple, sweet cherry)

•Pollen germination (on stigma). During this step, the pollen grain is hydrated on the stigmatic surface, and a germ tube begins to grow toward the ovary.

•Growth of germ tube to ovary. The tube grows through the style cells, and a "generative" nucleus divides into two "sperm" nuclei

•Fertilization of ovule. The germ tube enters the embryo sac, and one sperm nucleus fuses with the egg to form an embryo, while the other fuses with polar nuclei to become endosperm (food storage).

A honeybee’s collection of nectar and pollen is primarily for: A) The plant's benefit in pollination. B) Its own food. C) Strengthening the hive's defense. D) Wax production.

B) Its own food. The moving of pollen for the plant is an unintentional side effect of the honeybee's food collection.

Which of the following is a primary characteristic of wind-pollinated flowers, such as those of hazelnut or sweet corn? A) Showy petals B) Scent production C) Nectar production D) Extreme excess pollen production

D) Extreme excess pollen production. Wind-pollinated species are noted for producing pollen in extreme excess, unlike insect-pollinated flowers which are often showy and produce scent and nectar.

During pollen germination, the pollen grain is initially ___ on the stigmatic surface.

Hydrated (or Moistened). The pollen grain is moistened on the stigmatic surface to begin germination.

What is the approximate number of pollen grains produced per ovule for hazelnut? A) 7,000 B) 70,000 C) 250,000 D) 3,500

C) 250,000. Hazelnut produces 250,000 pollen grains per ovule, which is significantly more than apple (7,000).

The "generative" nucleus within a growing germ tube divides to form two __ nuclei.

Sperm. The generative nucleus divides as the tube grows to become two sperm nuclei.

In the process of fertilization, one sperm nucleus fuses with the egg to become the embryo, while the other fuses with the polar nuclei to become the ___.

Endosperm. The endosperm provides food storage for the developing embryo.

Which of the following conditions can lead to failure of fertilization despite successful pollination due to chemical interactions between pollen and pistil? A) Low population of pollinators B) Rain washing off stigmatic secretions C) Self-incompatibility D) Freeze during flowering

C) Self-incompatibility. Self-incompatibility is a mechanism where a plant's own pollen fails to achieve fertilization due to chemical interaction, preventing germination or proper germ tube growth.

True or False: Low temperatures can slow down insect pollinators but do not affect germ tube growth.

False. Low temperatures can slow both insect pollinators and germ tube growth.

What specific temperature and duration are recommended for soil pasteurization to prevent fungal pathogens like "damping off"? A) 100˚F for 15 minutes B) 180˚F for 30 minutes C) 200˚F for 60 minutes D) 150˚F for 45 minutes

B) 180˚F for 30 minutes. This specific treatment is recommended for soil pasteurization.

Which of the following is a disadvantage of using seeds for plant propagation? A) Relatively inexpensive B) Convenient for storage C) Genetic segregation of traits D) Long shelf life

C) Genetic segregation of traits. Plants grown from seed may not be genetically identical to the parent plant, which is a disadvantage, especially for self-incompatible plants or F1 hybrids.

Apples grown from seed may take approximately how many years before bearing fruit? A) 1 year B) 2 years C) 5 years D) 10 years

D) 10 years. Apple trees grown from seed may take up to 10 years to bear fruit.

What two conditions are primarily maintained for the long-term storage of most horticultural crop seeds to preserve viability and vigor? A) High temperature, high humidity B) Low temperature, low humidity C) High temperature, low humidity D) Low temperature, high humidity

B) Low temperature, low humidity. These conditions are the opposite of those that promote germination and are crucial for long-term seed storage.

The National Seed Storage Lab, an important gene bank, is located in which state? A) Indiana B) Colorado C) California D) Washington

B) Colorado. The National Seed Storage Lab is in Colorado and stores seeds, often in liquid nitrogen.

Which of the following is NOT an advantage of using seeds for plant propagation? A) Many seeds produced from a single plant B) Disease-free propagation C) Time to maturity D) Naturally dormant in many cases

C) Time to maturity. The long time to maturity for some plants grown from seed (e.g., apples, potatoes) is listed as a disadvantage.

What information is NOT typically required on a seed label in Indiana, according to regulations? A) Percent pure seed B) Seed color C) Percent weed seed D) Date of testing

B) Seed color. Seed labels typically include percent pure seed, percent weed seed, percent germination, and date of testing, but not seed color.

True or False: All seeds will germinate readily under standard conditions once they are mature.

False. Some seeds are dormant and require specific treatments (temperature, abrasion, light) to break dormancy before they will germinate.

The uptake of water into a seed, which initiates germination, is called ___.

Imbibition. Imbibition is the initial process of water uptake by the seed, critical for germination.

After imbibition, a developing seedling is highly sensitive to what environmental stress? A) High humidity B) Dehydration C) Low oxygen D) Excess light

B) Dehydration. Once imbibed and development initiated, the seedling becomes very sensitive to dehydration.

In direct seeding, why is it important to plant seeds at an appropriate depth? A) To maximize exposure to sunlight. B) To allow the seed to dry out quickly. C) To ensure the soil doesn't dry out too quickly and the seedling can emerge before reserves are exhausted. D) To prevent access by soil microbes.

C) To ensure the soil doesn't dry out too quickly and the seedling can emerge before reserves are exhausted. The depth must balance retaining moisture with allowing emergence.

Oxygen deprivation for germinating seeds most commonly results from: A) Excess light exposure. B) Waterlogging or flooding. C) Very high temperatures. D) Dry soil conditions.

B) Waterlogging or flooding. These conditions lead to poor drainage, reducing oxygen availability to the seed.

Which of the following is a common fungal pathogen group known to cause "damping off" in seedlings? A) Botrytis, Penicillium, Aspergillus B) Phytophthora, Pythium, Rhizoctonia C) Rusts, Smuts, Mildews D) Fusarium, Verticillium, Alternaria

B) Phytophthora, Pythium, Rhizoctonia. These are specifically mentioned as fungal pathogens causing "damping off."

True or False: Seedlings are well-protected from pathogens due to fully developed cuticles and defense mechanisms.

False. Young seedlings are relatively unprotected because their cuticle and other defenses are not fully developed.

What is a horticultural practice that aims to break seed dormancy by exposing seeds to specific temperature regimes, often cold and moist conditions? A) Scarification B) Stratification C) Priming D) Pelletization

B) Stratification. Stratification is the process of exposing seeds to specific temperature treatments to break dormancy.

The method of seeding where seeds are germinated in a nursery before being transplanted to the field is called __ seeding.

Indirect. Indirect seeding involves a two-stage process of starting seeds in a nursery then transplanting.

Which of the following specialized seeding methods involves the spray application of primed seed in a mix containing mulch and fertilizer? A) Liquid drilling B) Hydroseeding C) Direct seeding D) Broadcasing

B) Hydroseeding. Hydroseeding is the spray application of primed seeds in a mix.

What is a key characteristic of the liquid drilling method? A) Seeds are planted dry directly into the field. B) Seeds are coated with insecticide and fungicide before planting. C) Seeds are germinated until the radicle emerges and then mixed into a gel for sowing. D) Seeds are sown by hand to ensure precise placement.

C) Seeds are germinated until the radicle emerges and then mixed into a gel for sowing. This pre-germination step is characteristic of liquid drilling.

True or False: One advantage of indirect seeding is that it generally leads to lower costs compared to direct seeding.

False. Indirect seeding typically involves increased costs due to the two-stage process and higher management.

Which of the following is a common horticultural practice used to promote seedling growth in greenhouses by warming the soil? A) Bottom heating B) Top misting C) Air conditioning D) Light intensity reduction

A) Bottom heating. "Bottom heat" is used in greenhouses to adjust temperature for optimal germination.

Besides controlling moisture, what other preventive measure can be taken to protect seedlings from pathogens? A) Increasing light exposure B) Using purchased sterilized soil mix C) Planting seeds very deeply D) Applying excessive fertilizer

B) Using purchased sterilized soil mix. Other measures include clean containers, clean seed, and fungicides.

Which of the following can be added to seed coatings to inhibit the growth of fungal pathogens? A) Fertilizer B) Insecticide C) Fungicide D) Herbicide

C) Fungicide. Seed coatings can include fungicides to inhibit fungal growth.

What horticultural term refers to pollen provider trees that are carefully selected for cross-pollination in apple orchards?

Pollenizers. Pollenizers are the specific trees chosen to provide pollen for cross-pollination.

Which apple cultivar is specifically mentioned as producing sterile pollen? A) Red Delicious B) McIntosh C) Winesap D) Gala

C) Winesap. Winesap pollen is explicitly stated to be sterile.

For successful cross-pollination in apples, what characteristic of the pollenizer's bloom time is crucial? A) It must be earlier than the crop producer. B) It must be later than the crop producer. C) It must overlap the bloom time of the crop producer. D) It must be completely different from the crop producer.

C) It must overlap the bloom time of the crop producer. Overlapping bloom times ensure pollen availability when the crop needs it.

True or False: Crabapples are never used as pollenizers in commercial apple orchards due to their small fruit size.

False. Crabapples are sometimes used as pollenizers in apple orchards.

One recommended strategy for pollenizer location in an apple orchard involves placing them every third tree of every ___ row.

Third. One pattern shown is every third tree of every third row.

What is a common way horticulturists combat low natural insect pollinator populations in fruit and vegetable growing? A) Applying more pesticides. B) Bringing in hives of honeybees. C) Planting fewer flowering crops. D) Relying solely on wind pollination.

B) Bringing in hives of honeybees. Growers often bring in honeybee hives during flowering to ensure adequate pollination.

Which of the following factors is listed as potentially reducing bee flight? A) High temperature B) Low humidity C) Rain D) High population of other flowers

C) Rain. Rain, along with wind, can reduce bee flight, impacting pollination.

A failure of pollination can occur if rain washes off ___ secretions, which are necessary for pollen adherence and germination.

Stigmatic. Rain washing off stigmatic secretions can reduce pollen adherence and germination.

What happens to the "tube nucleus" once the germ tube begins to grow toward the ovary? A) It divides into two sperm nuclei. B) It guides the growth of the germ tube. C) It fuses with the egg. D) It becomes the endosperm.

B) It guides the growth of the germ tube. The sources state the pollen grain contains one nucleus that is the tube nucleus and one nucleus that will divide.

What is the approximate market value of seeds worldwide for propagating plants? A) $2.3 billion B) $23 billion C) $230 million D) $230 billion

B) $23 billion. The market for seeds used for plant propagation is stated to be a $23 billion market worldwide.

True or False: One disadvantage of indirect seeding is that it generally leads to a later crop maturity compared to direct seeding.

False. Indirect seeding actually results in the crop maturing earlier because seeds are germinated in a nursery first.

For most horticultural crops, viability and vigor are maintained when seeds are stored under conditions that are the _ of those that promote germination.

Opposite. Storage conditions (low temperature, low humidity) are opposite to germination conditions (adequate moisture, appropriate temperature).

What is "germplasm" in the context of the National Seed Storage Lab? A) A type of fungicide coating for seeds. B) A specialized nutrient solution for seed germination. C) A gene bank for preservation of genetic material. D) A pathogenic organism affecting seedlings.

C) A gene bank for preservation of genetic material. The National Seed Storage Lab is described as a repository for many species, important for germplasm preservation as a gene bank.

Potatoes grown from seed take approximately how many years to produce tubers? A) 1 year B) 2 years C) 3 years D) 5 years

B) 2 years. Potatoes grown from seed take 2 years to produce tubers.

The process of breaking seed dormancy by physically abrading or weakening the seed coat is called ___.

Scarification. Scarification involves physical treatments like abrasion to break dormancy.

In a well-drained, porous medium, what is readily available for seed germination? A) Carbon dioxide B) Oxygen C) Excess moisture D) Sunlight

B) Oxygen. Oxygen is readily available if the seed is planted in a well-drained, porous medium.

True or False: Controlling moisture is a key preventive measure against pathogens, as many thrive under high humidity conditions.

True. Many pathogens thrive under high humidity, so controlling moisture helps prevent them.

Which of the following is an example of a self-pollinating plant? A) Apple B) Sweet Cherry C) Tomato D) Hazelnut

C) Tomato. Examples given for self-pollination include tomato, peach, and pea.

The growth of the germ tube is influenced by compounds secreted by the _ tissue.

Style. The style tissue secretes compounds that influence the growth rate of the germ tube.

What are the two major uses of seeds in agriculture, as mentioned in the sources? A) For pest control and soil enrichment. B) As a plant part harvested for food and for propagating plants. C) For biofuel production and pharmaceutical extraction. D) For genetic engineering and hybridization.

B) As a plant part harvested for food and for propagating plants. These are the two major uses outlined.

When seed development occurs, it triggers the development of what?

Fruit. Seed development triggers fruit development.

True or False: Low temperature can accelerate germ tube growth, making fertilization more likely.

False. Low temperature slows germ tube growth, potentially hindering fertilization.

Which of the following is explicitly mentioned as a factor that can reduce natural insect pollinator populations? A) Excessive rainfall B) Strong winds C) Habitat destruction D) High weediness

C) Habitat destruction. Habitat destruction, disease, and pests (mites) are listed as reasons for low natural insect populations.

What is the main benefit of "primed seed" used in hydroseeding? A) It allows for longer storage. B) It prevents genetic segregation. C) It promotes rapid seedling growth. D) It makes seeds lighter for spraying.

C) It promotes rapid seedling growth. Pre-germinated or "primed" seeds promote rapid growth.

Why is careful selection of pollenizer trees necessary for apple orchards? A) To ensure uniform fruit color. B) Because apples require cross-pollination. C) To reduce the need for irrigation. D) To prevent disease spread.

B) Because apples require cross-pollination. Apples explicitly require cross-pollination, making pollenizer selection critical.

If an apple orchard uses the pollenizer location strategy of "every fifth row," what might be the variety planted in those specific rows? A) Winesap B) Red Delicious C) McIntosh D) Honeycrisp

C) McIntosh. The example given for "every fifth row" showed McIntosh as the pollenizer variety.

Which of the following is considered a “prenatal” care aspect for plants according to the seedling establishment objectives? A) Promoting seed germination. B) Monitoring soil moisture for seedlings. C) Protecting from pathogens after emergence. D) Transplanting seedlings to the field.

A) Promoting seed germination. This relates to the initial stage of the plant's life, prior to seedling growth.

What is the purpose of the endosperm that forms after fertilization? A) It becomes the plant's root system. B) It provides food storage for the embryo. C) It develops into the fruit wall. D) It aids in pollen germination.

B) It provides food storage for the embryo. The other sperm nucleus fuses to become endosperm (food storage).

True or False: In commercial seed sales, seed quality is of minimal importance once the seeds are distributed.

False. Seed quality is important in commercial sales, and federal and state regulations exist to ensure it.

What is one disadvantage of direct seeding, particularly for very small seeds? A) It requires extensive mechanization. B) It is not well suited for very small seeds. C) It ensures a good stand of plants without soil preparation. D) It makes crop maturity later.

B) It is not well suited for very small seeds. Direct seeding is convenient and mechanized but not ideal for very small seeds.

Which term describes the condition where a seed will NOT germinate under standard conditions and requires specific treatments to break dormancy?

Dormancy. This refers to seed dormancy where seeds require specific treatments to germinate.

What can happen to pollen shed or movement in wind-pollinated species during periods of rain? A) It can be enhanced. B) It can be prevented. C) It becomes more targeted. D) It encourages insect activity.

B) It can be prevented. Rain can prevent pollen shed or movement, especially in wind-pollinated species.

Besides habitat destruction, what other biological factors can lead to low natural insect pollinator populations? A) Excess pollen production. B) Disease and pests (mites). C) Competition from other pollenizer trees. D) Self-incompatibility in plants.

B) Disease and pests (mites). These are specifically mentioned alongside habitat destruction.

Which of the following is a criterion for seeds used in propagation related to their overall vigor? A) Percent pure seed B) Rate of germination C) Percent weed seed D) Storage temperature

B) Rate of germination. Viability and vigor are measured by percent seed germination, rate of germination, and rate of seedling growth.

When a plant exhibits self-sterility, its own pollen may fail to achieve fertilization due to a ___ interaction between the pollen and pistil.

Chemical. Self-incompatibility is explained as a chemical interaction preventing fertilization.

True or False: For seed production in insect-pollinated plants, a 1-mile isolation distance is generally needed.

False. Insect-pollinated plants typically require a 1/4 mile isolation distance for seed production, unlike wind-pollinated plants which need 1 mile.

The germ tube grows between and through cells of the ___.

Style. The tube grows between and through style cells.

What is the approximate number of pollen grains per anther in an apple flower? A) 20 B) 3,500 C) 70,000 D) 7,000

B) 3,500. An apple flower has 20 anthers, each with 3,500 pollen grains.

What is the primary purpose of using plastic wrap in greenhouse (indirect) seeding? A) To provide structural support for seedlings. B) To retain water and maintain moisture. C) To block excessive sunlight. D) To prevent pest infestations.

B) To retain water and maintain moisture. Plastic wrap is used to retain water, though caution is advised due to pathogen growth in high humidity.

If a plant is a "self-incompatible obligate outcrosser," what characteristic of its pollen would you expect? A) Its pollen would germinate readily on its own stigma. B) Its own pollen would not achieve fertilization on itself. C) It would produce very few pollen grains. D) Its pollen would be sterile on all other plants.

B) Its own pollen would not achieve fertilization on itself. An obligate outcrosser cannot be fertilized by its own pollen.

What is the process where a pollen grain, after being hydrated, begins to grow a tube towards the ovary?

Pollen germination. This is the third step in the process, following anthesis and pollination.

Horticulturists consider pollination and fertilization to be critical processes in the production of what two plant parts?

Fruit and seed. These processes are critical for fruit and seed production.

True or False: Competition for insects from other flowers (weediness) can negatively impact pollination success in a crop.

True. Avoiding weediness is mentioned as a way to prevent competition for insects.

In liquid drilling, what is mixed with the pre-germinated seeds to be sown in the prepared field? A) Dry powder fertilizer B) A gel containing fertilizer C) Mulch D) Water only

B) A gel containing fertilizer. The germinated seeds are mixed into a gel that contains fertilizer.

What is the benefit of "clean seed" in preventing seedling pathogens? A) It helps the seed germinate faster. B) It reduces the introduction of pathogens that might be carried on the seed. C) It makes the seed more attractive to pollinators. D) It ensures genetic purity.

B) It reduces the introduction of pathogens that might be carried on the seed. Using clean seed is a preventive measure against pathogens.

Which step in the process of pollination and fertilization involves the fusion of one sperm nucleus with the egg to form the embryo? A) Pollination B) Pollen germination C) Fertilization of ovule D) Growth of germ tube

C) Fertilization of ovule. This fusion is the definition of fertilization in this context.

What defines "anthesis" in the context of plant reproduction? A) The growth of the germ tube. B) The transfer of pollen to a stigma. C) The shedding of pollen. D) The fusion of nuclei.

C) The shedding of pollen. Anthesis is defined as pollen shed.

True or False: Genetic segregation of traits means that plants grown from seed are always genetically identical to the parent plant.

False. Genetic segregation of traits means that plants grown from seed may not be genetically identical to the parent plant.

Why are seeds considered convenient for storage? A) They are always very small. B) They are naturally dormant in many cases. C) They require continuous watering. D) They have a very short shelf life.

B) They are naturally dormant in many cases. Their dormancy allows for convenient, long-term storage.

What is a specific defense mechanism that is not fully developed in young seedlings, making them vulnerable to microbes? A) Root hairs B) Cuticle C) Chlorophyll D) Stomata

B) Cuticle. The cuticle and other defenses are not fully developed in young seedlings.

Which of the following is an example of a cross-pollinated plant mentioned in the sources? A) Pea B) Peach C) Tomato D) Sweet cherry

D) Sweet cherry. Sweet cherry and apple are given as examples of cross-pollinated plants.

If the germ tube grows too slowly, it can lead to what issue? A) Failure of anthesis. B) Failure of fertilization even with successful pollination. C) Excessive pollen shed. D) Self-pollination.

B) Failure of fertilization even with successful pollination. Slow germ tube growth is listed under "What Can Go Wrong?" for failure of fertilization.

Why might a horticulture grower choose indirect seeding over direct seeding, despite the increased costs? A) To minimize overall crop management. B) To delay crop maturity. C) To ensure good stand establishment. D) To simplify mechanization.

C) To ensure good stand establishment. Indirect seeding is chosen because it ensures good stand establishment and earlier maturity, despite higher costs and complexity.

The overall process of successful establishment of seedlings requires a rapid transition from dry seed to an ___ plant.

Autotrophic. The conclusion states that successful establishment requires a rapid transition from dry seed to an autotrophic plant.

What is the approximate shelf life of many seeds that makes them convenient for storage? A) Short B) Average C) Long D) Indefinite

C) Long. Long shelf life is listed as an advantage of using seeds for propagation.

What are the two types of nuclei contained within a pollen grain that is ready for germination? A) Embryo nucleus and endosperm nucleus. B) Generative nucleus and sperm nucleus. C) Tube nucleus and generative nucleus. D) Polar nucleus and egg nucleus.

C) Tube nucleus and generative nucleus. The pollen grain contains one tube nucleus and one generative nucleus.

True or False: For optimal germination, field planting should strictly adhere to the calendar date, regardless of environmental conditions.

False. In the field, planting depends on environmental conditions and weather, not necessarily the calendar.

What common issue, especially in temperate regions like N. Georgia, can determine a fruit grower's profitability in apple orchards? A) Soil erosion. B) Pollination & Fertilization. C) Pest resistance. D) Water availability.

B) Pollination & Fertilization. P&F is a critical aspect of fruit production in these regions, determining profitability.

How often are seeds typically regrown at the National Seed Storage Lab to maintain germplasm? A) Annually B) Every few years C) Decennially D) Only when requested

B) Every few years. Seeds are regrown every few years at the National Seed Storage Lab.

Which of the following conditions can reduce pollen adherence to the stigma and pollen germination? A) Strong wind B) High temperature C) Rain washing off stigmatic secretions D) Low pollinator population

C) Rain washing off stigmatic secretions. This specifically impacts adherence and germination.

What is a specific benefit of applying fertilizer as a seed coating? A) To make the seed heavier. B) To stimulate growth. C) To prevent insect damage. D) To inhibit fungal growth.

B) To stimulate growth. Fertilizer is applied as a coating to stimulate growth.

True or False: A major objective of studying seed germination and seedling establishment is to learn about horticultural practices that promote these processes.

True. One of the stated objectives is to learn about horticultural practices that promote seed germination and seedling growth.

The "second step" in the critical processes for fruit and seed production is ___.

Pollination. Flowering is the 1st step, pollination the 2nd, and fertilization the 3rd.

If a grower avoids "weediness" in their fields, what problem are they trying to mitigate in relation to pollination? A) Soil nutrient depletion. B) Competition for insects from other flowers. C) Excessive water runoff. D) Spread of fungal diseases.

B) Competition for insects from other flowers. Avoiding weediness helps prevent competition for pollinating insects.