Question

Water containing cavities in vascular bundles occurs in
A. Sunflower
B. Maize
C. Pinus
D. Cycas

Answer 1

Water containing cavities in vascular bundles is found in a plant that is an angiosperm belonging to the family Gramineae. This plant is a monocot that can be used as a source of food for animals and humans, biofuels, etc.

Complete answer:
Option (A) is incorrect. Sunflower is a dicot stem plant that belongs to the family Asteraceae. It possesses a vascular system that is of collateral, conjoint, and open type. Thus, water containing cavities in vascular bundles does not occur in sunflowers.
Option (B) is correct. Maize is an annual grass that belongs to the family Gramineae. It possesses a vascular system that is of collateral, conjoint, and closed type in which the lowermost xylem vessels and xylem parenchyma dissolve to form the water-containing cavity called protoxylem cavity or lacuna or lysigenous cavity.
Option (C) is incorrect. Pinus is a gymnosperm that belongs to the family Pinaceae. The vascular system of Pinus possess only tracheids and no vessels and thus, the vascular bundle in Pinus is of collateral, endarch, and open type with no water containing cavities.
Option (D) is incorrect. Cycas is a gymnosperm that belongs to the family Cycadaceae and lacks xylem vessels. Therefore, water-containing cavities in vascular bundles do not occur in Cycas.

Hence, the correct answer is option (B).

Note: The monocots possess collateral, conjoint, and closed vascular bundles which means that the phloem is present on the outer side, vascular bundles are arranged in the same radius, and cambium is absent between the xylem and phloem, respectively. The dicots possess open vascular bundles which mean cambium is present between the xylem and phloem that will promote secondary growth.