Chapter 33

During winter or periods of drought, which one of the following plant hormones inhibits growth and seed germination? a. ethylene c. gibberellin b. abscisic acid d. auxin

Auxin causes a shoot to bend toward light by a. causing cells to shrink on the dark side of the shoot. b. stimulating growth on the dark side of the shoot. c. causing cells to shrink on the lighted side of the shoot. d. stimulating growth on the lighted side of the shoot.

Plant hormones act by affecting the activities of a. genes. b. membranes. c. enzymes. d. genes, membranes, and enzymes.

Buds and sprouts often form on tree stumps. Which hormone would stimulate their formation? a. auxin b. cytokinin c. abscisic acid d. ethylene

Match each definition with the correct term. a. phytochrome b. photoperiod c. sleep movement d. circadian rhythm e. thigmotropism f. phototropism g. gravitropism Bending of a shoot toward light

Match each definition with the correct term. a. phytochrome b. photoperiod c. sleep movement d. circadian rhythm e. thigmotropism f. phototropism g. gravitropism Growth response to touch

Match each definition with the correct term. a. phytochrome b. photoperiod c. sleep movement d. circadian rhythm e. thigmotropism f. phototropism g. gravitropism Cycle with a period of about 24 hours

Match each definition with the correct term. a. phytochrome b. photoperiod c. sleep movement d. circadian rhythm e. thigmotropism f. phototropism g. gravitropism Pigment that helps control flowering

Match each definition with the correct term. a. phytochrome b. photoperiod c. sleep movement d. circadian rhythm e. thigmotropism f. phototropism g. gravitropism Growth response to gravity

Match each definition with the correct term. a. phytochrome b. photoperiod c. sleep movement d. circadian rhythm e. thigmotropism f. phototropism g. gravitropism Folding of plant leaves at night

A certain short-day plant flowers only when days are less than 12 hours long. Which of the following would cause it to flower? a. a 9-hour night and 15 -hour day with 1 minute of darkness after 7 hours b. an 8 -hour day and 16 -hour night with a flash of white light after 8 hours c. a 13-hour night and 11 -hour day with 1 minute of darkness after 6 hours d. a 12 -hour day and 12 -hour night with a flash of red light after 6 hours

If apples are to be stored for long periods, it is best to keep them in a place with good air circulation. Explain why.

Write a short paragraph explaining why a houseplant becomes bushier if you pinch off its terminal buds.

A plant nursery manager tells the new night security guard to stay out of a room where chrysanthemums (which are short-day plants) are about to flower. Around midnight, the guard accidentally opens the door to the chrysanthemum room and turns on the lights for a moment. How might this affect the chrysanthemums? How could the guard correct the mistake?

A plant biologist observed a peculiar pattern when a tropical shrub was attacked by caterpillars. After a caterpillar ate a leaf, it would skip over nearby leaves and attack a leaf some distance away. Simply removing a leaf did not trigger the same change nearby. The biologist suspected that a damaged leaf sent out a chemical that signaled other leaves. How could this hypothesis be tested?

Imagine the following scenario: A plant biologist has developed a synthetic chemical that mimics the effects of a plant hormone. The chemical can be sprayed on apples before harvest to prevent flaking of the natural wax that is formed on the skin. This makes the apples shinier and gives them a deeper red color. What kinds of questions do you think should be answered before farmers start using this chemical on apples? How might the scientist go about finding answers to these questions?