Question

The bark of the tree comprises
A. All the tissues inside the cork cambium.
B. All the tissue outside the vascular cambium
C. Only the cork.
D. The cork and the secondary cortex.

Answer 1

Hint: Bark is a term used for tissues outside the vascular cambium. It is the outermost layer of woody plants. Bark refers to periderm and secondary phloem. It can be formed early or late in the season.

Complete answer:
Bark refers to all tissues outside the vascular cambium, including secondary phloem. Bark alludes to various tissue types, viz, periderm, and secondary phloem. The bark that is shaped early in the season is called an early or delicate/soft bark and the bark that is shaped in the late season is called late or hard bark. The bark is also differentiated into outer bark or rhytidome (consisting of dead cells tissues outside phellogen or cork cambium) and inner bark (of living cells e.g., secondary phloem, secondary cortex). The outer bark is constantly peeled off. The peeling of the bark may occur in sheets e.g., Eucalyptus or in irregular strips (Pinus). The vascular cambium is defined as the growth of tissues in the stem and roots of plants. The vascular cambium produces secondary xylem inwards, towards the pith, and secondary phloem outwards.

So, the correct answer is option B.

Note: The phellogen is a couple of layers thick. It is made up of slight walled and rectangular cells. Phellogen cuts off the cells on two sides. The outer cells differentiate into the cork, while the inner cells give rise to the secondary cortex or phelloderm. Phellogen, phellem and phelloderm are collectively known as periderm.