Chapter 22.2, Problem 5MI

Summary Introduction

To determine:

The sequence the layers of cells of roots beginning with the outermost layer.

Introduction:

Roots are the organs in vascular plants that anchorage the plant to the ground and transport water and other nutrients throughout the plant. Roots are of two types, secondary roots and primary roots. Primary roots grow downwards and secondary roots grow sideways.

Explanation of Solution

The root cells are divided into many layers, which are, epidermis, exodermis, cortex, endodermis, and pericycle.

According to the given layers of cells, epidermis is the outermost layer, then comes cortex, after cortex comes endodermis, and then the innermost layer of cells is pericycle.

Epidermis - It is the layer of cells that cover the stem, leaf, flower, root, seeds, and fruit. Epidermis is covered with waxy cuticle that protects plant from infection, injury, and water loss.

Cortex − It is a tissue in plants between the epidermis and the vascular. These cells store carbohydrates, latex, resins, and essential oils.

Endodermis - Single layer of cells that forms a waterproof seal around a root’s vascular tissue.

Pericycle - Layer of cells just within the endodermis that gives rise to lateral roots.