Question

Vascular tissues of angiosperms differ from those of gymnosperms in
A. presence of vessels in the xylem.
B. presence of well-developed sieve tubes in phloem
C. presence of companion cells in phloem
D. all of these

Answer 1

Hint: Vascular tissue system is a complex system and consists of one or more than one type of cells. They are found in the vascular system and are associated with some very important functions of the plant. The main cells of the vascular bundles are xylem and phloem and are associated with conduction of water and mineral nutrients.

Complete answer:
The vascular bundles include the important tissues of the plants that are associated with the process of conduction and transport of water, nutrients and other fluids to different parts of the plant. The main tissue types associated with this process are the xylem and the phloem. The xylem tissues are primarily responsible for distribution of water and minerals taken up by the roots and the phloem is responsible for distribution of nutrients and prepared food in form of sugars from the leaves to other parts of the plant.

The vascular system is found in both the gymnosperms as well as the angiosperms. The gymnosperms are the plants that produce exposed or naked seed. The seeds of the gymnosperms develop either on the surface of the leaves or scales as modified cones. Whereas the angiosperms are the plants in which the seeds are enclosed inside a covering or the seed coat.

In addition to the several differences, the properties of vascular bundles in the gymnosperms and the angiosperms are also quite different. In the gymnosperms and angiosperms, the vascular bundles contain two main conducting tissues which are the xylem and the phloem.

The xylem tissues consist of a specialized system of tissues consisting of vessels and tracheid. The vessel elements are also known as the trachea and are one of the different types of cells that are found in the xylem tissues. The xylems of the gymnosperms lack the vessel elements whereas the angiosperms contain vessel elements. In angiosperms, the vessels are the principal water-conducting cells.

Phloem cells are the tissues that are responsible for transportation of foods prepared in the leaves to different parts of the plants. It consists of different types as specialized cells such as sieve tubes, companion cells, phloem fibres and phloem parenchyma cells. The sieve tubes are concerned with the transportation of carbohydrates as prepared food from the leaves to the fruits and the roots. The companion cells and the sieve elements are closely associated with each other. The sieve elements and the companion cells are present in the phloem of the angiosperms while in the gymnosperms these are absent.

Hence, The correct answer is option (D).

Note: The xylem and phloem are the chief conducting cells that are associated with transport of nutrients to different parts of the plants. The xylem and phloem consists of some specialized. Xylem consists of vessel elements and tracheid. The phloem contains the sieve tubes, companion cells, fibres and other parenchyma cells. The gymnosperms do not contain the vessel elements as well as the sieve tubes and companion cells in the vascular system while these are present in the angiosperms.