MCQ IN MEDICINE

Detailed explanation-1: -Tyloses form in xylem vessels of most plants under various conditions of stress and during invasion by most of the xylem-invading pathogens. Tyloses are overgrowths of the protoplast of adjacent living parenchymatous cells, which protrude into xylem vessels through pits (Fig. 6-8).

Detailed explanation-2: -The balloon shaped structures tracheal plugs formed in the xylem vessels of heartwood, due to the intrusions of secondary xylem parenchyma are called tyloses. So, the correct option is ‘Tracheal plugs which plug the lumen of the vessel and tracheids’.

Detailed explanation-3: -These are tracheal plugs found in heart wood, due to which the heart wood becomes non-functional. These are balloon-like swellings of xylem parenchyma cells in the lumen of vessels.

Detailed explanation-4: -Tyloses are found in Secondary xylem. Tyloses are an outgrowth structure on parenchyma cells of secondary xylem vessels. The function of these cells is seen when there are unfavorable conditions like drought or plant or vascular bundles that are affected by some infection.