Question

The distinct cavity (lacuna) found in mature vascular bundle in maize stem is formed due to

• A. Lysis of xylem parenchyma with metaxylem vessels
• B. Dissolution of common walls between a few metaxylem elements and their consequent coalescence
• C. Disruption of protoxylern as well as lysis of adjacent xylem parenchyma
• D. Disruption of protoxylem with metaxylem

Answer 1

The correct option is C Disruption of protoxylern as well as lysis of adjacent xylem parenchyma

The xylem along with phloem makes up as the important aspect of the vascular system of the plants. The xylem contains parenchyma and fibers.
The protoxylem vessel in maize, which has been torn, because the stem continued to elongate long after the vessel finished differentiation - primary wall and its secondary wall become ripped apart and gives a tubular space, known as the "lacuna". This is due to the disruption of protoxylem and lysis of adjacent parenchyma cells.

The protoxylem vessels are formed early in the season, but during growth they are partly broken down and form an inter-nodal cavity.