Why Protect A Dying Leaf? Chapter 42 Opener Each fall color has a purpose, but scientists are still investigating the function of red anthocyanin pigments, which are synthesized just before the leaf drops. Why Protect A Dying Leaf?

Chapter #42 – Plant Anatomy & Nutrient Transport 7th Edition in Audesirk, Audesirk, and Byers Chapter #24 – Plant Anatomy & Nutrient Transport 42.1 - How Are Plant Bodies Organized; How Do They Grow? p. 860 42.2 - The Tissues and Cell Types of Plants? p. 862 42.3 - The Structures, Functions of Leaves, Roots, & Stems? p. 865 42.4 - How Do Plants Acquire Mineral Nutrients? p. 873 42.5 - How Do Plants Move Water Upward from Roots to Leaves? p. 876

Plant Anatomy Systems and Tissues How Are Plant Bodies Organized, and How Do They Grow? Flowering Plants Consist of a Root System and a Shoot System. As Plants Grow, Meristem Cells Give Rise to Differentiated Cells.

The Art and Science of Living Survive (live) Support the body Obtain water & nutrients Transport water & nutrients Obtain energy Grow and Develop Exchange gases ? FIGURE 42-1 Dicot flowering plant structures and functions Protection from Herbivory Reproduce

Angiosperms (Monocots and Dicots) Flowering plants (called Angiosperms) are divided into two groups (monocots and dicots) based on the structure of their flowers, leaves, vascular tissue, roots, and seeds. Largest phylum of living plants. 250,000 + species. Seeds enclosed by fruits.

[Family, Theophrastaceae] Theophrastus (370 – 286 B.C.) Father of Botany. Author of the oldest treatise on pure botany, Historia Plantarum, in which he described about 480 kinds of plants. [Family, Theophrastaceae]

Carl Linnaeus (1707-1778) Swedish naturalist Carolus Linnaeus was the first to formalize the use of higher taxa in his book Systema Naturae (1735), establishing the standard hierarchy taxonomy still in use today. In addition, Linnaeus devised logical rules to classify species that continued to be used by scientists for over 200 years.

Plant Anatomy Roots & Shoots Root and shoot systems are made up of basic plant organs: roots, leaves, stems, flowers. FIGURE 42-1 Dicot flowering plant structures and functions

Root System Functions Anchor plant. Absorb water and minerals. Store sugar as starch. Transport materials Produce some hormones. Interact with soil microbes.

Shoot System Functions Photosynthesis (primarily in leaves) Transport of materials (water, minerals, sugars, and hormones among leaves, flowers, fruits, and roots) Reproduction Hormone synthesis

Structure is used in classification Angiosperms (Monocots and Dicots) Structure is used in classification Monocots have one cotyledon (seed leaf) e.g. grasses, lilies, palms, orchids Dicots have two cotyledons (seed leaves) e.g. deciduous trees (drop leaves in winter), bushes, many garden flowers

Flowers Monocots: flower parts in 3’s Dicots: flower parts in 4’s, 5’s, 6’s

Leaves Monocots: parallel veins in leaves Dicots: network of veins in the leaves

Stems Monocots: small vascular bundles scattered throughout the stem. Dicots: large vascular bundles arranged in a ring around the stem.

Roots Monocots: fibrous root system with no main tap root. Dicots: Main tap root, with smaller side roots branching off.

Seeds Monocots: single cotyledon; endosperm and cotyledon are separate. Dicots: two cotyledons; endosperm is contained in the cotyledon.

Plant Tissues  Dermal Tissue  Ground Tissue  Vascular Tissue - Epidermis - Periderm  Ground Tissue - Parenchyma - Collenchyma - Sclerenchyma  Vascular Tissue - Xylem - Phloem

Dermal Tissue: Epidermis Covers flowers, seeds, fruit. Secretes a waxy substance called cuticle (cuticular membrane - hydrophobic) as waterproofing. May produce special structures such as hairs (root hairs). Why?

Dermal Tissue: Periderm Replaces epidermis on roots and stems of woody plants with age. Composed mainly of thick, waterproof cork cells. Protects stems and roots. Anchor system (doesn’t absorb water & minerals).

Plant Tissues Parenchyma Collenchyma Sclerenchyma FIGURE 42-5 The structure of ground tissue (a) Parenchyma cells are living and serve many functions. They have thin, flexible primary cell walls. These parenchyma cells are used for starch storage in a potato. (b) Collenchyma cells are living and have thickened, but somewhat flexible, primary walls. They help support the plant body (as seen in this celery stalk). (c) Sclerenchyma cells have thick, rigid secondary cell walls and die after they differentiate. Illustrated are "stone cells" that give pear fruit its slightly gritty texture.

Ground Tissue: Parenchyma Non-dermal, non-vascular. Thin-walled cells Alive at maturity Many functions, including photosynthesis, starch storage, hormone production.

Ground Tissue: Collenchyma Flexible support tissue. Elongated cells with irregular shapes and unevenly thickened walls. Living at maturity.

Ground Tissue: Sclerenchyma Support tissue. Elongated cells with thick cell walls. Dead at maturity. Forms long fibers, or smaller sclerids (such as stone cells in pears).

Vascular Tissue: Xylem Sclerenchyma fibers Long, tube-like cells, joined end-to-end, that transport water and minerals from soil to leaves. Two types of cells: tracheids (in conifers) and vessel elements (in flowering plants).

Vascular Tissue: Phloem Tissue that transports dissolved sugars (sap) in a plant. Two types of cells: Sieve tubes (alive but no nucleus) Companion cells

In Review. . . . Monocots

In Review. . . . Dicots

Why Protect A Dying Leaf? Chapter 42 Opener Each fall color has a purpose, but scientists are still investigating the function of red anthocyanin pigments, which are synthesized just before the leaf drops. Why Protect A Dying Leaf?