Question

The hypodermis present in the maize stem is

A. Parenchymatous

B. Collenchymatous

C. Sclerenchymatous

D. Meristematic

Answer 1

Hint: Dermis is a Greek word that means skin. The hypodermis is a layer of skin that provides mechanical support to the stem. The hypodermis is made up of different types of permanent cells in different plants.

Complete answer:

The hypodermis present in the maize stem is Sclerenchymatous. Maize is monocot i.e. having single cotyledon, monocot stem have sclerenchymatous hypodermis. Other features present in the monocot stem from outside toward inside are:

i. Epidermis: It is the outermost layer of the primary plant body made up of compactly arranged cells forming a continuous layer, it acts as a protecting barrier. Epidermis cells are parenchymatous, it is usually a single layer thick.

ii. Hypodermis: It is found below the epidermis it is 2-3 layered thick made up sclerenchymatous in monocot stem, collenchymatous in dicot stem.it provides mechanical strength to the stem.

iii. Ground tissue: All the tissue other than the vascular bundle, epidermis, and hypodermis is called the ground tissue; it is made up of parenchymatous cells.

iv. Vascular bundle: vascular bundle consists of xylem and phloem, involved in the transportation of water and food in the plant. Xylem transport water from root to other plant parts, phloem transport food (starch) from leaf to other plant parts. Between xylem and phloem, another tissue called cambium is present which is responsible for secondary growth but it is not present in the monocot stem, monocot stem has a conjoint and closed vascular bundle (cambium is absent).

v. Pith: It is parenchymatous tissue present in the center, pith is absent in the monocot stem but it is large and conspicuous in dicots.

Additional Information: 

Parenchyma, collenchymas, and sclerenchyma are the permanent type of tissue that do not divide further. Whereas meristematic tissue is those which show division all the time. Permanent tissue is formed from meristematic tissue by differentiation.

Note: Hypodermis provide the mechanical support to the stem hence, the cells which constitute the hypodermis are of a thick wall. The collenchymatous cells are thickened in the corner and deposition consists of pectin, cellulose and hemicelluloses.