Question

The vascular bundles in the stems of most of dicots are conjoint, collateral and open. In each of these bundles

• A. Xylem completely surrounds the phloem on all sides but the two are separated by cambium
• B. Phloem completely surrounds the xylem and a strip of cambium separates the two
• C. Xylem and phloem are on the same radius with xylem situated towards the pith and phloem situated towards the pericycle and a strip of cambium separates the two.
• D. Xylem and phloem are on the same radius with phloem towards the pith and xylem towards the pericycle without a strip of cambium between them

Answer 1

The correct option is C Xylem and phloem are on the same radius with xylem situated towards the pith and phloem situated towards the pericycle and a strip of cambium separates the two.

In dicot stem, each vascular bundle consists of phloem on the outer side, xylem towards the inner side and a strap of cambium in between the two. Phloem and xylem tissues lie on the same radius . Such vascular bundles are known as conjoint (with both phloem and xylem), collateral (phloem and xylem on the same radius ) and open.

In monocot stem, phloem lies towards the outside and the xylem on the inner side. Cambium is absent as the whole procambium is consumed in the formation of vascular tissues. The vascular bundles are, therefore, conjoint, collateral and closed.

So, the correct answer is "option D"