Botany Study of Plants General Characteristics Autotrophs Eukaryotes

Botany Study of Plants

General Characteristics • • • Autotrophs Eukaryotes 400, 000 known species Cell walls Plastids Create food and habitat for animals

Phylum Bryophyta • Non-vascular plants (no true roots, stems or leaves) • Must live in moist environment • Must be small and close to ground

• • • P. Bryophyta, Class Muscopsida Mosses 9500 species Small, grow in clumps Reproduce by spores Pioneer plants

P. Bryophyta, Class Hepaticopsida • • Liverwarts 6000 species Very small Moist, warm environments

Vascular Plants • Have vascular tissue • 250, 000 species • Cell walls contain lignin (tough material for support) • Adapted to survive in tough conditions

Structure 1 • Roots – Absorb moisture and nutrients, anchor plants • Leaves – Use chlorophyll to produce food • Stems: Transfer materials between roots and leaves

Structure 2 • Vascular Tissue: • Xylem – Water and minerals from roots to other parts of the plants • Phloem – Sugars and organic material from leaves to other parts of the plants

Vascular Plant Groups • Seedless Plants • Seed Plants

Seedless Plants • Have sperm that swim to egg cells (in dew) • Simple plants • Do photosynthesis • 4 groups

Seedless Group 1 • Phylum Psilophyta – Whisk Ferns

Seedless Group 2 • Phylum Sphenophyta – Horse Tails

Seedless Group 3 • Phylum Lycophyta – Club Mosses

Seedless Group 4 • Phylum Pterophyta • – Ferns

Seed Plants • Reproduce with seeds • Seeds contain plant embryo and cotyledon (embryonic leaves) • Seeds help survive poor conditions

Groups of Seed Plants • Gymnosperm – naked seeds • Angiosperm – Flowering plants

Gymnosperms • Seeds in cones • Usually evergreens • Leaves needle-like or scale-like

Phylum Coniferophyta • Cone Bearers • Pine Trees

Phylum Cycadophyta • Cycads, • palm-like • (but not palms) • Ancient group

Phylum Ginkgophyta • • Gingko Leaves fan-shaped Only one species Ancient group

Phylum Gnetophyta • Ex: Welwitschia, Ephedra • About 70 species • Assumed to be the closest related to flowering plants

Angiosperm • Flowering Plants • About 235, 000 species

Phylum Anthophyta • Mature seeds are enclosed in fruits • Most species of plants • Flowers are reproductive structures

Class Monocotyledon • Produce seeds with 1 embryonic seed leaf • Flower parts usually in threes • Leaves with parallel veins • Almost all are herbaceous • Vascular bundles scattered • Roots diffuse

Examples

Class Dicotyledon • 2 Embryonic leaves (dicots) • Flower parts in 4 or 5’s • Leaf veins in a network • Vascular Bundles in a circle • Taproot

Examples of Dicots

Roots, Stems, and Leaves Plant Organs

RECORD ALL DETAILS ON SLIDES 31, 49, 50

• Roots: *Absorb water and nutrients *Anchor plants in ground • Stems *support plant body *transport nutrients among plant parts • Leaves *carry out photosynthesis *funnel water to roots sites for oxygen and *exchange carbon dioxide

Root, Stem, and Leaf Tissues Section 23 -1 Leaf Stem Root Dermal tissue Vascular tissue Ground tissue

Tissue Systems • Dermal: Page 581 *outer covering of plants *single layer of epidermal cells *covered with waxy cuticle that protects against water loss • Vascular: *xylem and phloem carry water and nutrients through the plant Page 582 • Ground: *parenchyma, collenchyma, schlerenchyma, support the plant and site of Page 583 photosynthesis • Meristematic: *only in tips of shoots and roots, responsible for plant growth Page 580

Fibrous Roots vs. Taproots • Fibrous roots are shallow and wide-reaching • Taproots are DEEP and concentrated downwards See pages 584 -585 in text

Figure 35. 14 Primary growth of a root

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

Figure 35. 3 Radish root hairs

Figure 35. 18 Organization of primary tissues in young stems

Layers of a Tree Trunk Section 23 -3 Wood Bark Contains old, nonfunctioning phloem that protects the tree Xylem: Heartwood Contains old, nonfunctioning xylem that helps support the tree Cork Cambium Produces protective layer of cork Phloem Transports sugars produced by photosynthesis Xylem: Sapwood Contains active xylem that transports water and minerals Vascular Cambium Produces new xylem and phloem, which increase the width of the stem

Stem adaptations • • See page 594 Tuber – stem growing underground (potato) Bulb – central stem surrounded by leaves (amaryllis) Corm – thickened stem that stores food (gladiolus) Rhizome – horizontal, underground stem (ginger)

Figure 35. 5 Simple versus compound leaves

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

Section 23 -5 Transpiration A B Evaporation of water molecules out of leaves. Pull of water molecules upward from the roots.

Section 23 -4 Function of Guard Cells – gas exchange (CO 2 in, O 2 out) Guard cells Inner cell wall Stoma Open Stoma Closed

Figure 35. 6 Modified leaves: Tendrils, pea plant (top left); spines, cacti (top right); succulent (bottom left); brightly-colored leaves, poinsettia (bottom right)

Water tranport • Capillary action – water moves upward through narrow tubes against the force of gravity (adhesion and cohesion)

Food Transport • Movement from source (where sugars are produced by photosynthesis) in leaves to where sugars are used or stored

Compare/Contrast Table Section 24 -1 Comparing Plant Propagation Methods Method Procedure Cuttings A length of stem that includes lateral buds is cut from the parent plant and partially buried in soil or rooting mixture to take root. Grafting A piece of stem is cut from the parent plant and attached to another plant. Budding A piece of lateral bud is cut from the parent plant and attached to another plant. Vegetative reproduction: takes place naturally; parent plant puts out runners that grow new plants (Ex. Strawberries)

Plant Responses (ADAPTATIONS) • Tropisms: responses of plants to environmental stimuli • Types of tropisms: gravitropism phototropism thigmotropism

Gravitropism and Phototropism Gravitropism: response of a plant to gravity – stems go up, roots go down Phototropism: response of a plant to light (“bending” toward the light)

Meristems control plant growth….

Thigmotropism • Response of plants to touch • Can stunt growth • Can cause “twining” of plant tendrils with vines and climbing plants *can have as a quick response – Venus flytrap

Photoperiodism and Flowering Section 25 -2 Short-Day Plant Midnight Noon Long Day Midnight Noon Short Day Midnight Noon Interrupted Night Long-Day Plant

Compare/Contrast Table – plant adaptations Section 25 -3 Comparing Carnivorous Plants, Epiphytes, and Parasites Characteristics Carnivorous Plants Epiphytes Parasites Environment bog host plant Method of obtaining nutrients leaves that trap and gather moisture digest insects from rainfall and produce their own food extract moisture and nutrients from host plant pitcher plant, sundew, Venus’ flytrap dodder, mistletoe Examples Spanish moss, orchid