Section 1: Plant Tissue Systems Preview Bellringer Key Ideas Plant Tissues Dermal Tissue System Vascular Tissue System Ground Tissue System Summary

Bellringer Think of outdoor plants and how their leaves, stems, and roots are adapted to the plants environment.

Key Ideas What three types of tissue are found in vascular plants? What is the dermal tissue system? What are two types of vascular tissue? What is ground tissue?

Plant Tissues Vascular plants have three tissue systems—the dermal tissue system, vascular tissue system, and ground tissue system. Dermal tissue forms the protective outer layer of a plant.

Plant Tissues, continued Vascular tissue forms strands that conduct water, minerals, and organic compounds throughout a vascular plant. Ground tissue makes up much of the inside of the nonwoody parts of a plant, including roots, stems, and leaves.

Structure of a Vascular Plant

Dermal Tissue System Dermal tissue covers the outside of a plant’s body. In the nonwoody parts of a plant, dermal tissue forms a “skin” called epidermis. Extensions of the epidermal cells on root tips, called root hairs, help increase water absorption.

Dermal Tissue System, continued Pores called stomata (singular, stoma) permit plants to exchange oxygen and carbon dioxide. A pair of specialized cells called guard cells border each stoma. Stomata open and close as the guard cells change shape.

Visual Concept: Dermal Tissue Systems in Plants

Control of Stomatal Opening

Visual Concept: Stomata

Vascular Tissue System Vascular plants have two kinds of vascular tissue, called xylem and phloem, that transport water, minerals, and nutrients throughout the plant. These tissues are composed of cells that are stacked end to end like sections of pipe. Xylem and phloem allow most vascular plants to grow to much larger sizes than nonvascular plants, which do not have xylem and phloem.

Vascular Tissue System, continued Xylem is composed of thick-walled cells that provide support and conduct water and mineral nutrients from a plant’s roots through its stems to its leaves. Phloem is made up of cells that conduct sugars and nutrients throughout a plant’s body.

Structure of Xylem

Visual Concept: Xylem

Structure of Phloem

Visual Concept: Phloem

Ground Tissue System The third type of tissue in vascular plants is ground tissue. Ground tissue makes up much of the inside of most nonwoody plants, where it surrounds and supports vascular tissue. Ground tissue contains many cell types, each with specific functions based on where the cells are located in a plant.

Visual Concept: Ground Tissue System in Plants

Summary Vascular plants have three tissue systems—the dermal system, vascular tissue system, and ground tissue system. Dermal tissue covers the outside of a plant’s body. In the nonwoody parts of a plant, dermal tissue forms a “skin” called the epidermis. Vascular plants have two kinds of vascular tissue, called xylem and phloem, that transport water, minerals, and nutrients throughout the plant body.

Summary, continued Ground tissue makes up much of the inside of most nonwoody plants, where it surrounds and supports vascular tissue.