According to the acid growth hypothesis, auxin works by
A) dissolving sieve plates, permitting more rapid transport of nutrients.
B) dissolving the cell membranes temporarily, permitting cells that were on the verge of dividing to divide more rapidly.
C) changing the pH within the cell, which would permit the electron transport chain to operate more efficiently.
D) increasing wall plasticity and allowing the affected cell walls to elongate.
E) greatly increasing the rate of deposition of cell wall material.

Question

Quizplus · Accepted Answer

The acid growth hypothesis proposes that auxin causes elongation of cells by increasing the plasticity of the affected cell walls. This allows the walls to stretch, leading to cell elongation. The acid part of the hypothesis refers to the role of proton pumps in the plasma membrane that move protons (H+) out of the cell, lowering the pH in the cell wall. This acidification leads to the activation of enzymes that modify the cell wall, increasing its plasticity and allowing it to elongate.

According to the Acid Growth Hypothesis, Auxin Works by