Interest Grabber Root Words The word root is not used only by biologists. Working with a partner, read over each of the following sentences. Try to determine the meaning of the boldfaced word(s) in each sentence. Then, explain how each use of the word root is related to the root of a plant. 1. The love of money is the root of all evil. 2. Tired of moving from place to place, he took root in our hometown. 3. The police were determined to root out the criminals.

Section Outline Roots A. Types of Roots B. Root Structure and Growth C. Root Functions 1. Uptake of Plant Nutrients 2. Active Transport of Minerals 3. Movement Into the Vascular Cylinder 4. Root Pressure

Essential Plant Nutrients Section 23-2 Essential Plant Nutrients Nutrient Nitrogen Phosphorus Potassium Magnesium Calcium Role in Plant Proper leaf growth and color; synthesis of amino acids, proteins, nucleic acids, and chlorophyll Synthesis of DNA; development of roots, stems, flowers, and seeds Synthesis of proteins and carbohydrates; development of roots, stems, and flowers; resistance to cold and disease Synthesis of chlorophyll Cell growth and division; cell wall structure; cellular transport; enzyme action Result of Deficiency Stunted plant growth; pale yellow leaves Poor flowering; stunted growth Weak stems and stunted roots; edges of leaves turn brown Thin stems; mottled, pale leaves Stunted growth; curled leaves

Figure 23–7 The Structure of a Root Section 23-2 Epidermis Root hairs Phloem Xylem Apical meristem Root cap Zone of maturation Zone of elongation Endodermis Ground tissue (cortex) Vascular Cylinder Ground tissue (cortex) Epidermis Endodermis Vascular cylinder Cross Section of Plant Root (magnification: 40x)

Figure 23–9 Water Transport in a Root Section 23-2 Figure 23–9 Water Transport in a Root Epidermis Endodermis Cortex Casparian strip Cell wall Root hairs Cortex Cell membrane Active transport of minerals Phloem Xylem Movement of water by osmosis Vascular Cylinder

KEY CONCEPT Roots and stems form the support system of vascular plants.

Roots anchor plants and absorb mineral nutrients from soil. Roots provide many functions. support the plant absorb, transport, and store nutrients root hairs help absorption

There are several parts of a root. root cap covers the tip

There are several parts of a root. root cap covers the tip apical meristem is an area of growth apical meristem

There are several parts of a root. root cap covers the tip apical meristem is an area of growth vascular cylinder contains xylem and phloem vascular cylinder

There are two main types of roots. Fibrous root systems have fine branches. Taproot systems have one main root. Fibrous root Taproot

Stems support plants, transport materials, and provide storage. Stems have many functions. support leaves and flowers house most of the vascular system store water Baobab trees Cactus

Stems support plants, transport materials, and provide storage. Stems have many functions. support leaves and flowers house most of the vascular system store water grow underground for storage Ginger rhizomes Potato tubers

Stems support plants, transport materials, and provide storage. Stems have many functions. support leaves and flowers house most of the vascular system store water grow underground for storage form new plants Strawberry stolons

Some stems are herbaceous and conduct photosynthesis.

Some stems can be woody, and form protective bark.

Primary growth increases a plant’s length. Secondary growth increases a plant’s width.

Tree rings help determine the age of a tree. heartwood bands bark one year of growth sapwood

Leaves—Up Close and Personal Section 23-4 Interest Grabber Leaves—Up Close and Personal Leaves absorb light and carry on most of the photosynthesis that occurs in a plant. For this reason, leaves are important plant structures. Examine the drawings of the three types of leaves shown in the next slide.

Interest Grabber continued Section 23-4 Interest Grabber continued Pin oak Dandelion Eastern white pine 1. Describe the shape of each leaf. 2. Describe the features of each leaf. 3. How is the structure of a leaf related to its function?

Section Outline Leaves A. Leaf Structure B. Leaf Functions 1. Carrying Out Photosynthesis 2. Gas Exchange

Function of Guard Cells Section 23-4 Function of Guard Cells Guard cells Guard cells Inner cell wall Inner cell wall Stoma Stoma Open Stoma Closed

Function of Guard Cells Section 23-4 Function of Guard Cells Guard cells Guard cells Inner cell wall Inner cell wall Stoma Stoma Open Stoma Closed

Figure 23–18 The Internal Structure of a Leaf Section 23-4 Figure 23–18 The Internal Structure of a Leaf Cuticle Veins Epidermis Palisade mesophyll Xylem Vein Phloem Spongy mesophyll Epidermis Stoma Guard cells

Label the Leaf

KEY CONCEPT Leaves absorb light and carry out photosynthesis.

Most leaves share some similar structures. The blade is usually broad and flat. collects sunlight for photosynthesis connects to the stem by a petiole blade petiole

Mesophyll is between the leaf’s dermal tissue layers. cuticle upper epidermis palisade mesophyll spongy mesophyll lower epidermis

Stomata open and close when guard cells change shape. Guard cells surround each stoma. Stomata open and close when guard cells change shape. When stomata are open, water evaporates and gas exchanges. Stomata close at night and when plant loses too much water. guard cells stoma

Leaves may be simple, compound, or double compound. Simple leaf Compound leaf Double compound leaf

Leaf veins may be parallel or pinnate. Pinnate veins Parallel veins

Leaf margins may be toothed, entire, or lobed. Toothed margin Entire margin Lobed margin

Most leaves are specialized systems for photosynthesis. There are two types of mesophyll cells. both types contain chloroplasts palisade mesophyll absorbs sunlight spongy mesophyll connects to stomata xylem phloem cuticle upper epidermis palisade mesophyll spongy mesophyll stomata lower epidermis

Leaves have many adaptations. for extreme temperatures, ex: pine needles

Leaves have many adaptations. for water loss, ex: cactus spines

Leaves have many adaptations. for aquatic environments, ex: water lily

Leaves have many adaptations. for getting food, ex: Venus’ flytrap