Question

Inner bark is composed of
A. Secondary xylem
B. Secondary phloem
C. Cork
D. Phellogen

Answer 1

In higher or woody plants, stems and roots are covered by an outermost layer called as bark. Examples of plants that bark are trees, shrubs or woody vines. It refers to all the tissues that lie outside vascular cambium.

Complete answer:
Inner bark is composed of Secondary phloem.
The bark includes tissues formed outside the vascular cambium, phellogen, phellen or phelloderm.
In plants, specialized tissues are developed that helps in the transport and conduction of different substances. These tissues are called vascular tissues or conducting tissues. The two types of conducting tissues found in plants are xylem and phloem.
(a) Xylem: Xylem works in conduction of water and minerals from root to different plant organs. It also provides physical support to plants. Xylem is located centrally in vascular bundles and is made up of xylem vessels, fiber, tracheids and xylem parenchyma. Xylem cells are dead cells and so xylem is dead tissues.
(b) Phloem: The function of phloem is conduction of food material from leaves to different organs of the plant body. Phloems is present on the outer side of vascular bundles. It provides mechanical support to plants. It is made up of phloem fibers, phloem, parenchyma, sieve tubes and companion cells. The cells in phloem are living cells so, phloem is a living tissue. The outer bark of plants is mainly made up of dead tissue and is formed by cork cambium and phellogen. Cork cells from the outer layer of stems and roots in wood plants.

Therefore, the correct answer is option (B) Secondary phloem.

Note: Cork cambium is called as phellogen and this is formed by dead cells. The cork, cork cambium and secondary structure together make up the perimeter. The outer bark, which is mostly dead tissue, is the product of the cork cambium (phellogen).