Question
Biology Question on Anatomy of Flowering Plants
In which of the following groups, the majority of plants contain the vascular tissue wherein the vessels and companion cells are absent in the xylem and phloem?
Angiosperms
Thallophytes
Bryophytes
Gymnosperms
Gymnosperms
Solution
Xylem and phloem are complex vascular tissues in plants. Xylem functions as a conducting tissue for water and minerals from roots to the stem and leaves. It is composed of four different kinds of elements, namely, tracheids, vessels, xylem fibres and xylem parenchyma in angiosperms. Gymnosperms lack vessels in their xylem. Phloem transports food materials, usually from leaves to other parts of the plant. It is composed of sieve tube elements, companion cells, phloem parenchyma and phloem fibres in angiosperms. Gymnosperms lack sieve tubes and companion cells.