Why Protect A Dying Leaf?

Why Protect A Dying Leaf?

Chapter #42 – 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 7th Edition in Audesirk, Audesirk, and Byers Chapter #24 – Plant Anatomy & Nutrient Transport

The Art and Science of Living Survive (live) Support the body Obtain water & nutrients Transport water & nutrients Obtain energy Grow and Develop Exchange gases ? 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.

Plant Anatomy Roots & Shoots • Root and shoot systems are made up of basic plant organs: roots, leaves, stems, flowers.

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

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 - 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

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 vesselelements (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