Question

A collateral vascular bundle is the one, in which xylem and phloem strands are present on the same radius with phloem towards :
A. Outer side of the xylem
B. Inner side of the xylem
C. All around the xylem
D. On both sides of the xylem

Answer 1

A vascular bundle is a part of the transport system in vascular plants. The transport itself happens in vascular tissue, which exists in two forms: xylem and phloem. Both these tissues are present in a vascular bundle, which in addition will include supporting and protective tissues.

Complete Answer:
There are four main types of vascular bundles. These are:-
1. Collateral Bundles
2. Bicollateral Bundles
3. Concentric Bundles
4. Radial Vascular Bundle.

1. Collateral bundle is a vascular bundle in which a phloem strand is present outside the xylem strand, on the same radius side by side. Cambium may be absent or present in between the xylem and phloem.
These are the types of collateral bundles: 1. Closed and 2. Open.
2. Bicollateral bundle is a vascular bundle which has the phloem situated on the peripheral as well as inner side of the xylem.
3. Concentric Bundle is a vascular bundle in which one type of vascular tissue surrounds the other type. In this, the phloem either encircles or is encircled by the xylem.
4. Radial Vascular Bundle is a vascular bundle, in which the strands of the primary xylem and primary phloem, are separated from each other by tissues which are not vascular ; and they occur at alternate radial locations. This can be significantly seen at the roots.

Thus, the correct option is A) Outer side of the xylem.

Note: Examples of the Collateral bundle include - Asparagus Stem and Dicotyledonous stem.
- Vascular bundles are also called “fascicles”. The Vascular tissue system in plants comprises these vascular bundles.
- The main parts of the vascular system are xylem and phloem.