Question

Bark includes?
A)Primary xylem and periderm
B)Primary phloem and primary xylem
C)Periderm & secondary phloem
D)Periderm and pith

Answer 1

Hint: In woody plants, the tissues that are located external to the vascular cambium or the tissue that are located outside the wood from the bark. The outer bark is composed of dead tissues and produces a bast. The dead tissues are termed as phellogen.

Complete answer:
The outermost and external layer of stems and roots of the woody plants is termed as bark. Shrubs, woody vines, and trees possess bark. The tissue that is located outside the vascular cambium produces the bark. It is composed of outer bark and inner bark which overlays the wood.

The living tissues in the older stems help to produce the inner bark and it constitutes the innermost area of the periderm. The xylem that is produced during the primary growth from the procambium of the apical meristems is also located in the primary xylem. The
inner soft bark or bast is established from the vascular cambium and primarily consists of secondary phloem tissue.
The dead cells in the barks are needed for gaseous exchange and are known as lenticels.

Hence, the correct answer is option (A)

Note: Bark gives rise to the thinner parts than the woody tissues of the stem. Both outer and inner bark is produced by the vascular cambium. The outer bark is composed of secondary xylem whereas the inner bark contains secondary phloem. The inner bark assimilates dead tissues and the outer bark sloughs off dead tissues.