Question

Balloon like swellings formed by xylem parenchyma inside the xylem vessels through pits are called ?

• A. Compound sieve plates
• B. Specialized secretory cell
• C. Callose plugs
• D. Tyloses

Answer 1

The correct option is D Tyloses

Tyloses are balloon like swellings formed by xylem parenchyma inside the xylem vessels through pits of vessel members and block water movement.

Tyloses are the parenchymatous outgrowth from vessel-parenchyma which pairs into the lumen of tracheary elements. These are naturally formed in heartwood and are observed in the xylem of leaves during senescence. Tyloses form in xylem vessels in response to various environmental stimuli.

Pollen tube walls of flowering plants contain callose that resides in the tube wall and forms the plugs that separate the growing tip from the evacuated tail. The callose plug keeps the pollen cytosol within a reasonably small volume and therefore has been thought to play an important role for fertilization.

Sieve plates are mostly located on the overlapping adjacent end walls. Specialized secretory cells predominate in the secretory tubules of control animals and appear as transitional cells in the tubular epithelium of salt-stressed animals.

Thus, the correct answer is option D.