Some seeds require light for germination. This process is controlled by the phytochrome system. Which of the following germination treatments would inhibit germination of such seeds?

SCIENTIFIC THINKING The discovery of auxin is a good example of how scientists build upon each other's work. For each of the three sets of researchers discussed in the chapter (the Darwins, Boyle-Jensen, and Went), write a one-sentence summary of what they discovered. If you were going to credit one person as being the 'discoverer' of auxin, who would it be?

A conformational change in a substance called phytochrome __________.

What happens immediately after a phytochrome is activated by light?

You are interested in determining what part of a plant senses the light, which leads to phototropism. A good first experiment would be to __________.

Photoperiodism is __________.

An Alaskan trapper worried about being attacked by grizzly bears left the lights on in his cabin all the time. Plants just outside the cabin flowered a month early. Which of the following best explains this?

A certain short-day plant flowers when days are less than 12 hours long. Which of the following treatments will result in flowering?

What are circadian rhythms?