Exam 37: Regulation of Plant Growth

Suppose that a scientist is experimenting in the laboratory with tissue culture methods. Pith tissue that was isolated has grown an undifferentiated mass of cells (called a callus), and that tissue has been divided up and placed in the following culture media: (1) necessary nutrients plus indoleacetic acid; (2) necessary nutrients plus zeatin (a cytokinin); (3) necessary nutrients plus equivalent concentrations of indoleacetic acid and zeatin; (4) necessary nutrients plus an excess of zeatin and minimal indoleacetic acid. Explain what happens to the mass of tissue under each condition.

Which of the following does not occur during the earliest stages of germination?

A protein pigment called phytochrome is thought to monitor photoperiod because

Which of the following statements about phytochrome P_r is true?

Which of the following is most important for the future survival of a young plant seedling that has not yet been exposed to light?

Genetic mutations that disrupt plant development are usually studied by means of

What hormonal influences are affecting a pea plant from the moment it is planted until its emergence?

Use the following to answer questions : Refer to the diagram below, showing seed germination. -Identify the molecules indicated by D in seed 4. What is their role?

In shoot phototrophic responses, auxin is transported _______ and _______ from the apical meristem.

As a first step in seed germination, the seed must

To be able to respond to environmental stimuli at any stage of development, plants employ sequences of biochemical reactions called

Which process is not directly affected by auxin?

Which of the following is not a plant hormone?

Growth of a shoot tip toward the light, which is called _______, is thought to be mediated by the actions of the hormone _______.

Which of the following suggests that plants produce gibberellins?

Ethylene

Recently, it has been discovered that both auxin and gibberellins have specific protein receptors which, when bound by hormone,

Auxins cause elongation by

Ethylene is produced by what part of a plant?

Which of the following enhance(s) energy storage in a small space?