Which of the following statements best summarizes the acid growth hypothesis in an actively growing shoot?
A) Auxin stimulates proton pumps in the plasma membrane and tonoplast.
B) Auxin-activated proton pumps lower the pH of the cell wall, which breaks bonds and makes the walls more flexible
C) Auxins and gibberellins together act as a lubricant to help stretch cellulose microfibrils.
D) Auxins activate aquaporins that increase turgor pressure in the cells.
E) Auxins and gibberellins are transported to the vacuoles to build up turgor pressure.

Question

Quizplus · Accepted Answer

The acid growth hypothesis states that auxin activates proton pumps in the plasma membrane and tonoplast to lower the pH of the cell wall, making it more flexible by breaking bonds between cellulose microfibrils. This allows for the stretching of the cell wall and overall growth of the shoot. Option A is partially correct but does not fully explain the acid growth hypothesis. Options C, D, and E are incorrect and do not relate to the acid growth hypothesis.

Which of the Following Statements Best Summarizes the Acid Growth