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
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