Question

Bicollateral vascular bundles are found in
A. Helianthus
B. Zee mays
C. Cucurbita
D. Dracaena

Answer 1

Hint: In bicollateral vascular bundles, xylem occupies the middle section of the bundle and this is flanked by stripes of cambium on both the inner and outer side, and then two patches of phloem.

Complete Answer:
The vascular tissue structure is made up of xylem and phloem, two diverse tissues that constitute discrete strands called vascular bundles. A few layers of meristematic cells are found between xylem and phloem in the stem of gymnosperm and dicotyledon. This is known as cambium. There are four types of vascular bundles.

Now, let us find the solution from the options-
Option A: In Helianthus, collateral closed vascular bundles are found. Therefore, this is the incorrect option.

Option B: In zee mays, collateral open vascular bundles are found and not bicollateral vascular bundles. Therefore, this is the incorrect option.

Option C: Bicollateral vascular bundles with the xylem found in the inner strand of the phloem and located in the stem are a type of conjoint vascular bundle. This is often seen in Cucurbita, the stems of the Cucurbitaceae family. Therefore, the option C is correct.

Option D: In Dracaena, concentric vascular bundles are found and not bicollateral vascular bundles. Therefore, this is the incorrect option.

Thus, the correct answer is option C)Cucurbita.

Note: The phloem is observed to be present on both sides of the xylem in certain bundles. Two cambium stripes also exist concurrently. In the following order, the different elements are arranged: outer phloem, outer cambium, xylem, inner cambium and inner phloem.