Question

The youngest layer of secondary xylem in a five year old dicot stem is found

• A. Just outside the cambium
• B. Just inside the cambium
• C. Adjacent to pith
• D. Adjacent to cortex

Answer 1

The correct option is B Just inside the cambium

In a dicot stem, by the end of the first year, the primary structure shows the growth of vascular and cork cambiums. The growth of the secondary xylem becomes continuous with the primary xylem. The secondary growth occurs both in the stele and cortex and though simultaneously, is caused by separate strips of secondary meristem. The cambial ring exhibits mitotic activity on both the sides and ones towards the inner surface results in the formation of xylem cells.