Question

The balloon shaped structures called tyloses

• A. Are extensions of xylem parenchyma cells
• B. Are linked to the ascent of sap through xylem vessels
• C. Originate in the lumen of vessels
• D. Characterize the sapwood

Answer 1

The correct option is A Are extensions of xylem parenchyma cells

The xylem vessels and tracheids of heartwood do not conduct sap. This is because they get plugged by balloon-like outgrowths of adjacent parenchyma cells into their lumens. They are not linked to ascent of sap as they block the conduction of sap. Tyloses do not originate in the lumen of the vessels. They characterize the heartwood and not the sapwood. Hence, the answer is "are extensions of xylem parenchyma cells".