Question 1

Pollen from a plant with the S₁S₂ genotype is recognized and allowed to germinate on the stigma of the same plant with the S₁S₂ genotype.According to the S-system hypothesis,this indicates that the plant is

Accepted Answer

The S-system hypothesis proposes that self-incompatibility in plants is controlled by a multi-locus gene system, with each individual having two of potentially many S-alleles (S₁, S₂, S₃, etc.). A plant with the S₁S₂ genotype will only allow germination and fertilization of pollen with different S-alleles, but not with the same S-alleles. Therefore, when the pollen from a plant with the S₁S₂ genotype is allowed to germinate on the stigma of the same plant with the S₁S₂ genotype, it means that the plant is self-compatible and can self-pollinate.

Question 2

Cottonwood,aspen,and willow trees have drab-colored flowers with no petals that appear before the tree's leaves are out in the spring;they are dioecious.What does that indicate about these trees?

Accepted Answer

The fact that these trees have drab-colored flowers with no petals that appear before the leaves are out in the spring and are dioecious (having separate male and female trees) suggests that their pollen is likely dispersed by wind rather than by insect pollinators. Color and shape of the flowers are not important for attracting pollinators in these trees.

Question 3

Plants in crop fields such as corn are genetically very similar.What are benefits of this phenomenon? What are pitfalls of that phenomenon?

Accepted Answer

Benefits-Harvest is synchronized;consistent,dependable crops.Pitfalls-Entire crop is genetically susceptible to diseases,insects,and weather problems.

Question 4

What is an essential part of alternation of generations in plants?

Accepted Answer

In alternation of generations, plants undergo mitosis to produce gametes in the gametophyte stage. Meiosis produces spores, not gametes, which then grow into gametophytes.

Question 5

If an ovary contains 50 ovules,what is the minimum number of pollen grains that must land in order to form 50 mature seeds?

Accepted Answer

The answer of If an ovary contains 50 ovules,what is...

Question 6

A summer occupation in the Corn Belt states is de-tasseling the corn: removing unwanted male flowers so that female flowers on the same plant are pollinated by the desired pollen for the hybrid corn.What does this tell you about corn?

Accepted Answer

Corn has separate male and female flowers on the same plant, making it monoecious with imperfect flowers.

Question 7

A population of flowers varies from deep blue to nearly white.Bees are active during the day and prefer color.Moths are active at night,when colors are not very visible and white is more conspicuous.Design a scenario in which the blue and white flowers form two species where there once was one species.You must end with a conclusion that the two new species cannot interbreed (a definition of a species).

Accepted Answer

The answer of A population of flowers varies from deep...

Question 8

What is not true about the carpel of a flower?

Accepted Answer

Meiosis of the megaspore does not form the eight nuclei of the embryo sac. It is the mitotic division of the haploid nucleus in the embryo sac that produces the eight nuclei.

Question 9

The flowering hormone is made in ________ and alters development of ________.

Accepted Answer

The answer of The flowering hormone is made in ________...

Question 10

A gardener in Canada wants to surprise his mother on her birthday and make her favorite Shrubalthea bush flower in May instead of the end of June.The bush is growing in the greenhouse.Which of the following might make the Shrubalthea bush flower early?

Accepted Answer

Grafting leaves of a Shrubalthea that was exposed to short nights can induce earlier flowering, as short nights simulate longer daylight conditions, which can trigger flowering in some plants.

Question 11

It is estimated that animal- or insect-pollinated plants produce 1000 pollen grains for each ovule;wind-pollinated plants produce 1,000,000 pollen grains for each ovule.What does that indicate about pollination systems?

Accepted Answer

The fact that wind-pollinated plants produce 1,000,000 pollen grains for each ovule indicates that wind pollination is less efficient than animal-assisted pollination. Animal-pollinated plants produce far less pollen grains in comparison, but are still able to achieve pollination and seed production. This suggests that wind-pollination may require a higher investment in energy and resources by the plant.

Question 12

The sperm and egg each contribute 50% of the nuclear genetic material to the zygote that becomes the embryo and the new plant.Mitochondria and plastids that become chloroplasts are passed primarily from the female parent.What feature of the male or female gametophytes accounts for this?

Accepted Answer

The female gametophyte, also known as the embryo sac, is formed from one surviving megaspore and therefore has more cytoplasmic content and organelles, such as mitochondria and plastids, than the smaller male gametophyte, which is formed in the anthers. As a result, the majority of plastids and mitochondria are inherited from the female parent.

Question 13

During self-fertilization,which of the following is absent?

Accepted Answer

During self-fertilization, the transfer of pollen from one plant to another is absent because self-fertilization involves the transfer of pollen within the same flower or between flowers of the same plant.

Question 14

What is the male gametophyte made of?

Accepted Answer

The male gametophyte, also known as the pollen grain, is made up of two cells - the generative cell and tube cell. The generative cell will divide to produce two sperm cells, while the tube cell will form the pollen tube which helps transport the sperm cells to the female gametophyte in the ovule.

Question 15

Most plants are adept at asexual reproduction.What is the probable explanation for the energy spent for sexual reproduction?

Accepted Answer

Sexual reproduction mixes up genes, leading to variation in a species, which can be beneficial in adapting to changing environments and avoiding genetic diseases. This provides an advantage over asexual reproduction, which passes on identical genes and limits genetic diversity.

Question 16

Which of the following correctly identifies the function of the flower part named?

Accepted Answer

Sepals protect the flower bud. Petals attract pollinators, not seed-dispersing animals. The stigma receives pollen, and the carpel is the female reproductive part of the flower, not specifically for attracting pollinators.

Question 17

What is the similarity between spores and gametes?

Accepted Answer

The answer of What is the similarity between spores and...

Question 18

While looking at a flower in your garden,you notice that it has carpels with very long styles and stamens with very short filaments.This plant is most likely to reproduce by

Accepted Answer

The long styles suggest that the flower is adapted for receiving pollen from other plants, making cross-pollination the most likely mode of reproduction. The short filaments suggest that the plant may not be well adapted for self-pollination. Asexually reproducing plants typically do not have flowers with carpels and stamens.

Question 19

How are the life cycles of liverworts and angiosperms alike?

Accepted Answer

Both liverworts and angiosperms have a life cycle that involves the production of spores by the sporophyte generation. This means that the sporophytes of both groups are responsible for producing the spores that give rise to the gametophyte generation. Therefore, choice E is the best answer.

Question 20

Home flower gardeners in northern latitudes like to grow plants that flower only in the spring or flower only in the late summer and fall.They are planting flowers that are most sensitive to

Accepted Answer

Flowering in plants is often regulated by photoperiod or the length of day and night. Plants that flower only in the spring or late summer and fall are responding to changes in night length, making option B the correct choice.

Quiz 40: Plant Reproduction