You Are Studying the Cellular Basis of Petal Coloration in the Flowering

question 25

Multiple Choice

You are studying the cellular basis of petal coloration in the flowering plant Ipomoea tricolor. These plants have colorful petals due to the presence of pH-sensitive vacuolar anthocyanins that change color from red/purple in acidic pH to blue at neutral pH. You treat petals with either vanadate (a specific inhibitor of P-ATPases) or bafilomycin (a specific inhibitor of V-ATPases) or both and compare the color with that of control petals, obtaining the results shown in the table below. Which of the following conclusions is consistent with these observations?

• A) Both P- and V-ATPases are required to sufficiently acidify the vacuoles in petal cells.
• B) P-ATPases are sufficient for acidification of the vacuoles in petal cells.
• C) V-ATPases are sufficient for acidification of the vacuoles in petal cells.
• D) Neither P- nor V-ATPases are necessary for vacuole acidification in petal cells.