Deck 25: Plant Reproduction

Question 1

A genus of primarily wind-pollinated plants includes one unusual species that has evolved to be pollinated by insects. Several morphological changes have accompanied this adaptation. The ______________ are more colorful, there is a nectary at the base of the ______________, the ________________ are shorter and produce sticky pollen, and the __________________ are stickier for enhanced pollen capture.

A) petals, stamens, sepals, carpels
B) petals, sepals, stamens, carpels
C) stamens, carpels, petals, sepals
D) petals, sepals, carpels, stamens

Answer 1

petals, sepals, stamens, carpels

Question 2

You are a landscape architect working on the grounds of a large estate. After you plant a dozen trees, the owner says, "There's been a mistake. The flowers on some of these willow trees look totally different! I specifically asked for Salix alba. You must have planted two different species." You refer to your tree guide, and read: "Salix alba - species of willow native to Europe and Asia, noted for the white undersides of leaves. Insect pollinated, dioecious. Grows 10-30m tall." How do you respond to the client?

A) "Sorry about that sir, I will dig up the wrong trees right away."
B) "Don't worry, the trees with the smaller flowers just haven't undergone phase change yet."
C) "Don't worry, when the shorter trees reach full size, they will grow the other kind of flower."
D) "Don't worry, Salix alba is dioecious, meaning each tree has either male or female flowers. That is why they look different."

Answer 2

"Don't worry, Salix alba is dioecious, meaning each tree has either male or female flowers. That is why they look different."

Question 3

Thanks to a novel recessive mutation, a certain plant species has begun to invade colder Arctic regions outside of its normal range. However, this cold-tolerant mutation has not yet become fixed in the population. A second mutation arises that promotes self-pollination. Do you predict that the self-pollination allele will be selected for in the Arctic regions? Why or why not?

A) Yes. The self-pollinated plant is more likely to maintain the cold-tolerant mutation, and plants in the Arctic are unlikely to be visited by pollinators.
B) No. Outcrossing is always beneficial, since it enhances genetic diversity.
C) No. Plants that produce flowers must be cross-pollinated for proper seed development.
D) Cannot make a prediction from the information given.

Answer 3

Yes. The self-pollinated plant is more likely to maintain the cold-tolerant mutation, and plants in the Arctic are unlikely to be visited by pollinators.

Question 4

A gourmet ice cream company started a charitable campaign to save an insect species. Which species are they most likely to care about, and why?

A) Cockroaches. In the 1950s, the company nearly eradicated a certain species of roach, but subsequently learned they are valuable pollinators.
B) Cochineal insects. They are the only natural source of red food dye.
C) The honeybee. They explain that half of their ingredients, and a significant portion of our food supply in general, rely on bee pollination, and bee populations have been suffering from the poorly-understood Colony Collapse Disorder.
D) Butterflies. They explain that half of their ingredients, and a significant portion of our general food supply, rely on butterfly pollination, and butterfly populations have suffered from the spread of "bug zappers" in the suburbs.

Question 5

You and your neighbor each have a holly bush in your yards. You carefully water and care for your bush, but it fails to produce berries. Your neighbor, on the other hand, neglects his holly, yet it produces gorgeous red berries each year. Finally, in frustration, you replace your holly with a rose bush. The next year, your neighbor's holly bush has no berries at all. What happened?

A) Roses compete for the same insect pollinators as holly bushes.
B) Holly plants are dioecious. Yours was a male that was needed to pollinate the neighbor's female.
C) Roses secrete a chemical that inhibits the reproduction of neighboring plants.
D) The neighbor's bush became infected with the same disease that yours had.

Question 6

What is the best description of double fertilization in angiosperms?

A) One sperm fertilizes the egg, which develops into the embryo; the other sperm fertilizes the ovary, which becomes the fruit.
B) One sperm fertilizes the egg, which develops into the embryo; the other sperm fertilizes the polar nuclei, which forms the endosperm.
C) One sperm fertilizes the egg, which develops into the embryo; the other sperm fertilizes the polar nuclei, which forms the seed coat.
D) One sperm fertilizes the egg, which develops into the embryo; the other sperm produces the pollen tube.
E) One pollen grain fertilizes the embryo sac; the other sperm fertilizes the pollen grain.

Question 7

You go to the movies with a friend, and he refuses to share your popcorn. He says that he heard that movie theatre popcorn is triploid. What is the most likely explanation for this?

A) Most corn is genetically modified by large agricultural companies.
B) The buttery topping on movie theatre popcorn causes chromosomal abnormalities.
C) Popcorn is made from a different species of maize than regular corn.
D) All popcorn is triploid, because the starchy part of the kernel is triploid endosperm tissue.

Question 8

Which structure does NOT represent a mode of vegetative reproduction?

A) runners
B) rhizoids
C) adventitious plantlets
D) suckers
E) rhizomes
F) stolons

Question 9

Kentucky Bluegrass is a widespread turfgrass used for lawns throughout the United States. In some regions, strains have developed desirable disease-resistant properties. However, Kentucky Bluegrass typically develops by apomixis. Plant breeders say this creates both a challenge and an opportunity for engineering novel strains. Why?

A) In apomixis, new plants develop from underground horizontal stems. This allows for fast propagation of new strains, but all progeny are identical to the parent.
B) Plants that develop by apomixis are naturally tolerant of herbicides. As a result, herbicide tolerance genes cannot be used as selectable markers for a transgene, but herbicides can be used to keep the resulting culture pure.
C) Since the progeny of apomixis are triploid, hybrids have an imbalance of parental genes. However, this may be desirable if a higher proportion of one allele is beneficial.
D) If a seed develops by apomixis, it will be identical to its parent. Hybridization with another strain requires special techniques. However, once a hybrid strain is developed, apomixis ensures its reliable propagation.

Question 10

Walking through the botanical garden with a friend, you spy a rare and beautiful variety of Hosta. "Oh I would love to have one of those!" you exclaim. "But they cost a king's ransom." Your friend snips off a tiny piece of the shoot and says, "I'll grow you one. I'll just take it back to lab and..."

A) "culture an individual plantlet for you..."
B) "use enzymes to break down the cell walls..."
C) "grow up a callus..."
D) "wait for somatic embryos to form..."

Question 11

Your rich uncle, an eccentric botanist, has died. The will states: "Just like my favorite plants, I keep my wealth buried underground." Where do you dig for his treasure?

A) In the peanut field. Legumes have root nodules which house symbiotic ants that harvest honey, a nutritional "treasure".
B) In the herbaceous perennial bed. Perennial stems die each fall, but underground nutrient stores provide energy for regrowth each spring.
C) In the annual plant bed. Annuals store nutrients in extensive underground root systems that allow them to regrow each year.
D) Dig up the roots of the mistletoe plants, which store large quantities of water.

Question 12

Two users of an internet gardening site are arguing. Sarah, an organic gardener from Maine, refers to her snapdragon plants as "annuals". Marco, a farmer from Italy, scoffs and declares them "perennials". Who is right?

A) Sarah is right. A snapdragon plant only returns for 3-4 years, and thus is not a true perennial.
B) Marco is right. With enough inorganic fertilizer, the snapdragon can regrow. All "annuals" are just undernourished perennials.
C) They are victims of bad translation software. The plant Marco refers to reseeds itself year after year and thus is a perennial.
D) They are both right. In a Mediterranean climate, the snapdragon re-emerges from its rootstock each spring. In colder climes, it must be re-planted each year. A plant that is perennial in its native habitat may be an annual in other climates.

Question 13

Heirloom plants are treasured for their flavorful produce and true-breeding progeny that allow gardeners to avoid repeatedly purchasing seed from agribusiness conglomerates. What special effort is required to save seed from heirloom biennials such as carrots?

A) Since carrots produce large roots, they do not devote many resources to seed development. The roots must be trimmed before collecting seed.
B) Since carrots build up so much beta-carotene, they do not devote many resources to seed development. A yellow carrot variety will produce better seeds than a darker one.
C) Since carrots are related to wild weeds, they are often cross-pollinated. The green top must be bagged to ensure self-pollination.
D) Biennials do not produce seed until the second year of growth. Although carrot roots are normally harvested after one season, they must be allowed to grow another year for seed collection.

Question 14

Scientists have confirmed by carbon dating that seeds dormant for up to 2000 years can successfully germinate. Based on the requirements for germination, what research expedition should you join in order to retrieve some ancient but viable seeds?

A) A trip to Indonesia, where the civet cat eats and expels coffee beans, producing a gourmet coffee known as Kopi Luwak.
B) A trip to the Irish marsh, where wet peat creates anaerobic conditions, and your colleagues hope to unearth a bog mummy.
C) A trip to the Burgess Shale in Canada, where your paleontologist colleagues have found fossils from the Cambrian era.
D) A trip to the arid Dead Sea region, where your historian colleagues have found a storeroom of wax-sealed jars.

Question 15

Pea plants are self-pollinators. What can you further deduce about peas? (Check all that apply.)

A) Peas will be more resistant to garden pests than other plants.
B) Peas are less likely to invade highly variable natural environments than other plants.
C) A gardener planning to collect heirloom seeds can plant different varieties of peas near each other.
D) Peas will be more resistant to new plant diseases.
E) To perform his pea cross-pollination experiments, Gregor Mendel must have first removed the stamens from flowers to prevent self-pollination.

Question 16

The gene wooden leg is necessary for development of phloem. If you stained a late-stage embryo with an anti-Wooden Leg antibody, in what tissue would you expect to see staining?

A) endosperm
B) ground meristem
C) procambium
D) protoderm

Question 17

If development of the shoot apical meristem failed in a bean embryo, which tissues would still be able to form? (Check all that apply.)

A) cotyledons
B) leaves
C) root
D) stem
E) suspensor

Question 18

A forest ranger surveys the burned landscape of his park following a destructive wildfire. "Well, there's one silver lining," he says, "We ought to see some unusual plants sprouting up in the next few years." Why?

A) Damage to predator populations will allow vulnerable plants to survive the seedling stage.
B) The growth of plants is normally limited by carbon availability in the soil.
C) Some species' pollen is only carried and activated by smoke.
D) Some seeds are adapted to germinate only when heated by a fire.
E) In many plants, the seedling's suspensor can more easily push into ashes than into overgrown soil.

Question 19

A number of plants in a wilderness area carry a mutation that makes their soft, colorful fruits bitter and unpalatable. Would you expect this mutation to increase or decrease in frequency in the plant's population?

A) The mutation will decrease in frequency.
B) The mutation will increase in frequency.
C) It depends whether they are pollinated by the wind, birds, or insects.
D) It depends whether the plants use sexual or asexual reproduction.

Question 20

Which "vegetables" are technically fruits? (Check all that apply.)

A) lettuce
B) green onion
C) tomato
D) spinach
E) peapod
F) carrot

Question 21

A seed contains an embryo mutant for gibberellic acid (GA) receptors. What phenotype would you expect to result in the seedling?

A) No mutant phenotype until the plant is older.
B) Poor growth due to unusable nutrient reserves.
C) Malformed cotyledons due to defects in development.
D) Yellow instead of green due to chloroplast failure.