Biology 23.1

23-1 Specialized Tissues in Plants

Chapter 23: Roots, Stems, and Leaves

Epidermal Cell

• Cell that makes up the dermal tissue, which is the outer covering of a plant

Vessel Element

• In angiosperms, xylem cell that forms part of a continuous tube through which water can move

Sieve Tube Element

• Phloem cell that is joined end-to-end to similar cells to form sieve tube

Companion Cell

• Phloem cell that surrounds sieve tube elements

Parenchyma

• Type of ground-tissue cell with a thin cell wall and large central vacuole

Collenchyma

• Type of ground tissue cell with a strong, flexible cell wall; helps support larger plants

Sclerenchyma

• Type of ground-tissue cell with an extremely thick, rigid cell wall that makes ground tissue tough and strong

Meristem

• Cluster of tissue that is responsible for continuing growth throughout a plant’s lifetime

Meristematic Tissue

• Tissue that controls the internal movement of materials in the body, as well as external movement

Apical Meristem

• The group of undifferentiated cells that divide to produce increased length of stems and roots

Differentiation

• The process in which cells become specialized in structure and function

• Three of the principal organs of seed plants are roots, stems, and leaves

• Plants consist of three main tissue systems: dermal tissue, vascular tissue, and ground tissue

• Vascular tissue contains several types of specialized cells. Xylem consists of tracheidsand vessel elements. Phloem consists of sieve tube elements and companion cells.

• Meristematic tissue is the only plant tissue that produces new cells by mitosis.