Question

Tyloses are
(A) Tracheal plugs which plug the lumen of the vessels and tracheids
(B) Compound sieve plates
(C) Specialised secretory cells
(D)Laticiferous channels

Answer 1

Tyloses are spheroidal protoplasmic bulges or outgrowths that are generally formed when the adjacent parenchyma cells, axial parenchyma, or ray cells, protrude into the dead axial conducting cells. Tyloses are present only in land plants. Tyloses help in forming a stronger heartwood by slowing the process to rot.

Complete answer:
(A) The balloon-shaped structures called tracheal plugs in the xylem vessels of heartwood, due to the intrusions of secondary xylem parenchyma are called tyloses. So, the correct option is (A) Tracheal plugs that plug the lumen to the vessel and tracheids.
(B) Sieve plates and sieve tubes and sieve bundles are found in the angiosperms. Sieve plates are the pores in the plant cell walls that facilitate the transport of materials .each sieve tube element is normally. This option is wrong.
(C) Most secretory cells are specialized cells obtained from materials belonging to other tissues, mainly epidermis of parenchymatous tissues. So, this option is wrong.
(D) A laticifer is the elongated secretory cell that is found in the leaves and stems of the plant. These plants produce latex and rubber as secondary metabolites.these are divided into many types. So this option is wrong.

The right answer is (A) – ‘Tracheal plugs which plug the lumen of the vessels and tracheids’.

Note: Tyloses are formed because of stress occurred due to drought and infections. They are outgrowths on parenchyma cells of xylem vessels of secondary heartwood. Tyloses will fall from the sides of cells and form a dam-like structure in the vascular tissue to prevent /block further damage to the plant.