Exam 27: Regulating Growth and Development: the Plant Hormones

Gibberellins promote fruit development in some species in which auxin does not.

Second messengers do not cross the plasma membrane and enter the cytosol.

Which of the following statements about abscisic acid is FALSE?

The most widespread and active brassinosteroid is:

In the ABA-induced closing of stomata, the following ion fluxes occur across guard cell plasma membranes: first calcium ions flow ______, then anions flow ______, and finally potassium ions flow ______.

In the ethylene signaling pathway in Arabidopsis, when ethylene is absent, then ____ is active.

Gibberellins promote a ______ orientation of the microtubules underlying the plasma membrane, and ethylene promotes a ______ orientation.

In roots, a substance transported in a basipetal direction is transported toward the root tip.

Which of the following statements about second messengers is FALSE?

Dwarf mutant plants are short because they:

Auxin is the only plant hormone known to be transported in a polar manner.

Salicylic acid regulates thermogenesis in members of the arum family.

Which of the following statements about 2,4-D is FALSE?

In stems, polar auxin transport occurs mainly in the:

______ activates the biosynthesis of ________, which then activates the genes that encode protease inhibitors.

One of the principal roles of abscisic acid is in leaf, flower, and fruit abscission.

Based on the results of experiments with cultured mesophyll cells of Zinnia elegans, you would predict that if brassinosteroids were excluded from the culture medium, no tracheary elements would be formed.

In germinating barley seeds, the ______ releases gibberellins, which then diffuse to the ______ where they stimulate the synthesis of hydrolytic enzymes.

The receptors for both auxin and gibberellin are located in the:

In the ethylene signaling pathway in Arabidopsis, when the EIN2 protein is activated which of the following happens next?