Question

‘Hadrome’ term is applicable to
A. Phloem
B. Xylem
C. Cortex
D. Epidermis

Answer 1

Hint: Like animals, plants also have a tissue system. Plant tissue can be classified into two types- meristematic tissues and permanent tissues. Meristematic tissues consist of undifferentiated cells that help in plant growth. These tissues also give rise to secondary tissues. Permanent tissues are made up of specialized cells that have an assigned role in the plant body. Both meristematic and permanent tissues can be further subdivided into various types.

Complete answer:
Phloem is a vascular tissue that can transport food to various parts of the plant body. Sieve tubes, companion cells, phloem fibres, and phloem parenchyma cells make up the phloem tissue. Permanent tissues are formed when meristematic tissues differentiate. Apical meristem found on the tips of the root and shoots of a plant differentiates to form the primary phloem.
Xylem is the other vascular tissue that carries water and minerals to various parts of the plant body. This tissue has a woody part and non-woody part. The woody part of the xylem is called hadrome. The specialized cells found in the xylem are tracheids, vessels, xylem fibres, and xylem parenchyma.
Between the epidermal layer of cells and the vascular tissues lies a layer of cells called the cortex. The cortex is made up of parenchyma cells. Parenchymatous cells are a part of the ground tissue system. parenchymatous cells perform functions such as storage of starch, photosynthesis, etc. The parenchymatous cells of the cortex store food in them.
The epidermis is the outermost layer or the surface layer of the plant. The cells of this layer belong to the dermal tissue system. Depending upon the location, the cells of the epidermis layer have different functions. However, one of the main functions of this layer is to protect the inner layer of cells.

Hence, the correct answer is option (B).

Note: The permanent tissue can be classified into three types- dermal tissue, ground tissue, and vascular tissue. Also depending upon the homogeneity or heterogeneity permanent tissue can be classified into- simple (same cell type) and complex (different cells are present) tissues. Examples of cells of the former type are parenchyma, sclerenchyma, and collenchyma. The vascular tissues i.e. xylem and phloem are complex.