Question 1

If a hypocotyl does not elongate during seed germination and early seedling growth,where will the cotyledons be?

Accepted Answer

If the hypocotyl does not elongate, the cotyledons will remain in the ground with the seed coat.

Question 2

A researcher found a beautiful plant while traveling in Alaska and collected its seeds.When she came back to Florida,she soaked some seeds in pure water and some in water with the hormone gibberellin.When she put seeds to grow in soil,only seeds soaked with gibberellin germinated.The seeds that were soaked in pure water did not germinate because of _____.

Accepted Answer

The answer of A researcher found a beautiful plant while...

Question 3

The egg of a plant has a haploid chromosome number of 12 (n = 12).What is true about the number of chromosomes in the cells of other tissues of this plant?

Accepted Answer

In plants, the endosperm is typically triploid (3n), so if the haploid number is 12, the endosperm would have 36 chromosomes.

Question 4

Endosperm is a major part of monocot seeds.In most dicots,_____.

Accepted Answer

In most dicots, endosperm is formed after double fertilization, but its nutrients are later repackaged into the cotyledons, which become the primary source of nutrients for the developing embryo. Therefore, endosperm is not a major part of dicot seeds.

Question 5

After double fertilization in angiosperms,what development sequence is correct?

Accepted Answer

After double fertilization in angiosperms, the ovary wall develops into the fruit. The embryo in the seed develops into the embryo and the endosperm is formed from the fusion of the polar nuclei with a sperm cell. The ovule itself does not develop into a fruit, but it is enclosed within the fruit. The carpel does not develop into the cotyledons, but the carpel is the female reproductive structure that contains the ovule, which eventually develops into the seed.

Question 6

Which of these events occurs first in seed germination?

Accepted Answer

Water uptake is the first step in the process of seed germination.

Question 7

Angiosperms are unique in having double fertilization that forms endosperm.What is true about double fertilization in angiosperms?

Accepted Answer

In angiosperms, double fertilization involves the fusion of one sperm cell with the egg to form the zygote, and another sperm cell with the two polar nuclei to form the endosperm. Therefore, choice D is the correct answer.

Question 8

Mosses and ferns tend to be most abundant in warm,moist climates.Why do mosses and ferns have problems with reproduction in deserts?

Accepted Answer

Mosses and ferns require water for their sperm to swim to the egg for fertilization, which is challenging in dry desert environments.

Question 9

Charles Darwin experimented with reactions of grass seedlings (monocots)relative to applied auxin (a plant hormone)and light.He used the youngest seedlings with a structure that dicots do not have.What is the name of that structure?

Accepted Answer

The structure that monocots possess but dicots do not is called coleoptile. It is a protective sheath that covers the emerging shoot of the monocot embryo as it grows through the soil. Charles Darwin used the coleoptile of grass seedlings in his experiments on plant hormone auxin and light responses.

Question 10

It is possible to make seedless tomatoes by removing the anthers of the flower and putting a hormone (auxin)on the stigma of the tomato flower.Weekly applications are required.Over the course of development,the stigma and style fall off,and the ovary develops into a normal-looking tomato with no seeds.Normally,seed and fruit formation are coordinated using hormone signaling.What does the application of auxin indicate?

Accepted Answer

The application of auxin indicates that there is a lack of natural auxin produced in the developing seed, which is necessary for seed and fruit formation. The applied auxin must substitute for this natural auxin source in order to prevent seed formation and instead stimulate the development of the ovary into a seedless tomato. Options A and B are incorrect because they describe natural processes that occur during pollination and fruit development, respectively, but do not explain the purpose of the applied auxin.

Question 11

Suppose that 100 pollen grains land on a stigma,and 50 mature seeds are formed in the fruit.What does this indicate about the pollination process and success?

Accepted Answer

The answer of Suppose that 100 pollen grains land on...

Question 12

Which of these events happens first in nearly all seed germination?

Accepted Answer

The radicle, which is the embryonic root, is the first part of the seedling to emerge from the seed and grows downward into the soil to absorb water and nutrients.

Question 13

Gardeners purchase packets of seeds that are put in the ground and germinate.Native plant seeds usually need a scarification treatment or a real or simulated winter (stratification),some seeds need light,and others need a smoke treatment.What do these adaptations to the environmental conditions reveal about where the plants grow?

Accepted Answer

The answer of Gardeners purchase packets of seeds that are...

Question 14

The hammer orchids resemble female thyranide wasps and release a chemical signal called pheromone to deceive male thyranide wasps and accomplish pollination.Compared to food-deceiving orchids,is it more or less likely that pollen of hammer orchid will be transferred to the flower of the same species than to flower of the different species?

Accepted Answer

The hammer orchid's mimicry of female wasps is a highly specialized form of deception, targeting a specific pollinator. This specialization increases the likelihood that the pollen will be transferred to flowers of the same species, as the male wasps are more likely to visit other hammer orchids in search of mates.

Question 15

Which of these is not a step in the formation of an embryo from a zygote in the seed?

Accepted Answer

The emergence of the root and shoot systems from the seed occurs after the embryo has formed and the seed germinates, not during the formation of the embryo from a zygote.

Question 16

Use the following information when answering the corresponding question(s).
Whitebark pine (Pinus albicaulis)is an important tree at timberline in the Rocky Mountains and Sierra Nevadas.Its large seeds provide food for grizzly bears,squirrels and other rodents,and many birds,including its major seed disperser,the Clark's nutcracker (Nucifraga columbiana).The Clark's nutcracker has a pouch below its tongue for carrying seeds,which it deposits 10 m to 12 km from a tree.Clark's nutcrackers often store many more seeds than they need for survival;in a single year,one bird can store more than 30,000 seeds.They store 3-5 seeds from one cone in each cache and typically use the seeds for food during spring and summer.When these birds do not harvest the seeds,the seeds germinate and form new whitebark pine trees.(D.F.Tomback.1982.Dispersal of whitebark pine seeds by Clark's nutcracker: A mutualism hypothesis.Journal of Animal Ecology 51:451-67. )
-Refer to the paragraph on whitebark pine seed dispersal by Clark's nutcracker.To conclude that the Clark's nutcracker is a mutualistic seed disperser,not just a predator,you would need to determine that _____.

Accepted Answer

The mutualism hypothesis is based on the assumption that the seeds dispersed by the Clark's nutcracker have a higher probability of germinating and producing seedlings than seeds eaten by other animals or left on the ground. Therefore, it is essential to determine if the seeds in the caches can germinate and establish new trees to support the idea that the Clark's nutcracker is a mutualistic seed disperser. Option A is not relevant since it is clear that the whitebark pine can still spread without the Clark's nutcracker. Option B is incorrect as it suggests that the bird is not benefiting from the dispersal process. Option D is not supported by the information in the paragraph since it is stated that bears and other animals also eat whitebark pine seeds.

Question 17

Use the following information when answering the corresponding question(s).
Whitebark pine (Pinus albicaulis)is an important tree at timberline in the Rocky Mountains and Sierra Nevadas.Its large seeds provide food for grizzly bears,squirrels and other rodents,and many birds,including its major seed disperser,the Clark's nutcracker (Nucifraga columbiana).The Clark's nutcracker has a pouch below its tongue for carrying seeds,which it deposits 10 m to 12 km from a tree.Clark's nutcrackers often store many more seeds than they need for survival;in a single year,one bird can store more than 30,000 seeds.They store 3-5 seeds from one cone in each cache and typically use the seeds for food during spring and summer.When these birds do not harvest the seeds,the seeds germinate and form new whitebark pine trees.(D.F.Tomback.1982.Dispersal of whitebark pine seeds by Clark's nutcracker: A mutualism hypothesis.Journal of Animal Ecology 51:451-67. )
-Refer to the paragraph on whitebark pine seed dispersal by Clark's nutcracker.Clark's nutcracker stores seeds in caches.What type of spatial distribution of whitebark pine would you expect to find in an area with a high population of Clark's nutcrackers?

Accepted Answer

Since Clark's nutcracker only stores seeds in certain locations, the spatial distribution of whitebark pine would be clumped around those cached seed locations.

Question 18

Unripe fruits protect seeds from predation and early germination.What is the major function of ripe fruits?

Accepted Answer

The major function of ripe fruits is to disperse the seeds to new locations, increasing the chances of successful germination and growth.

Question 19

You find a fruit that has little hooks around the outside of the pericarp.You can assume that _____ is/are the pollinator.

Accepted Answer

The answer of You find a fruit that has little...

Question 20

Before plowing a field,a farmer thought the bare field looked weed-free.Three days after plowing and turning over the soil,he was amazed to see thousands of tiny seedlings.What is the most likely reason for the mass germination of seeds?

Accepted Answer

Plowing the field likely exposed small seeds to light, which is a common trigger for germination in many plant species.

Quiz 40: Plant Reproduction