1). Flowers must
a). be insect pollinated.
b). show indeterminate growth.
c). be part of the angiosperm life cycle.
d). be self-incompatible.
2). In Iowa, a company called Team Corn works to ensure that fields of seed corn outcross so that hybrid vigor can be maintained. They do this by removing the staminate (i.e., pollen-producing) flowers from the corn plants. In an attempt to put Team Corn out of business, you would like to develop genetically engineered corn plants that
a). contain Z-genes to prevent germination of pollen on the stigmatic surface.
b). contain S-genes to stop pollen tube growth during self-fertilization.
c). express B-type homeotic genes throughout developing flowers.
3). Monoecious plants such as corn have either staminate or carpelate flowers. Knowing what you do about the molecular mechanisms of floral development, which of the following might explain the development of single-sex flowers?
a). Expression of B-type genes in presumptive carpels will generate staminate flowers.
b). Expression of A-type genes in presumptive stamens will generate carpelate flowers.
c). Restricting B-type gene expression to presumptive petals will generate carpelate flowers.
d). All of these are correct.
4). You have been asked to collect plant sperm for a new plant breeding program involving in vitro fertilization. Which of the following tissues would be a good source of sperm?
5). Street trees (those lining the roads) are generally male. This reduces the cleanup of the streets because the trees only produce pollen, not fruits. Therefore, the kinds of trees that are normally chosen as street trees are
d). trees producing perfect flowers.
e). You cannot have a tree that is only male.
6). If you wanted to create a super tobacco plant to increase the number of leaves/acre on a tobacco farm, which of the following strategies would potentially work?
a). Suppress more root growth in the plants.
b). Decrease expression of the LEAFY gene in the shoot apical meristem.
c). Harvest lower leaves as the plant is growing so that flowering is delayed.
d). Remove flowers so that the plant will produce more vegetative internodes than normal.
7). One of the most notable differences between gamete formation in animals and gamete formation in plants is that
a). plants produce gametes in somatic tissue, while animals produce gametes in germ tissue.
b). plants produce gametes by mitosis, while animals produce gametes by meiosis.
c). plants produce only one of each gamete, while animals produce many gametes.
d). plants produce gametes that are diploid, while animals produce gametes that are haploid.
8). If you were to discover a flower that was small, white, and heavily scented, its most likely pollinator would be
9). Under which of the following conditions would pollen from an S2S5 plant successfully pollinate an S1S5 flower?
a). If you used pollen from a carpelate flower, to fertilize a staminate flower, it would be successful.
b). If the plants used gametophytic self-incompatibility, half of the pollen would be successful.
c). If the plants used sporophytic self-incompatibility, half of the pollen would be successful.
d). Pollen from an S2S5 plant can never pollinate an S1S5 flower.
10). You have been commissioned by kindergarteners across the country to develop a dandelion-breeding program to improve the quality of dandelion bouquets to give to mom. Initially, you are very excited about this project until you remember that
a). dandelions reproduce asexually using runners.
b). dandelion flowers set seed without fertilization.
c). if dandelion flowers are not yellow, they will fail to attract the correct pollinators.
d). dandelions are really gymnosperms.
Answer: b Test Your Visual Knowledge
1). Describe what is taking place in this figure, and predict the genotypes of the staminate and carpelate tissue.
Answer: This must be an example of gametophytic self-incompatibility. Some but not all of the pollen that lands on the stigma fails to develop fully. Since pollen is haploid, you can infer that the staminate tissue had an S1 S2 genotype and produced pollen that was either S1 or S2. The carpelate tissue would have to have one of the alleles, but not the other. Let's say that the carpelate tissue was S1 S3. In this case, the S1 pollen would not fully develop, but the pollen with the S2 allele would be fine.
Apply Your Knowledge
1). We often have the impression that plants lack the ability to move around in the environment. This, however, is far from the truth. Discuss the variety of ways that plants successfully move throughout the environment.
Answer: Plants use animals to move across large distances. The flowering plants are particularly good at dispersing their offspring. Animals carry fruit and seed over long distances. Pollen can be carried to another plant of the same species by wind or an animal pollinator allowing plants to mate even though they are quite far apart. Unlike most animals, however, the plant does not have its own organs for locomotion and must piggyback on an animal to get around in the environment.