Holly Springs High School Plants Holly Springs High School Biology

What is brown and really really sticky?

Plant defense Tomato plant releases chemicals that attract wasps: Click HERE Hornworm on tomato plant with wasp larvae. (Shooting Creek, NC 07/16)

Plants -Multicellular -Autotrophic -Eukaryotes -Cell Walls made of cellulose -Carry out photosynthesis using the green pigments chlorophyll a and b

Plant Life Cycle Plant Needs Two alternating phases - Sporophyte – diploid (2n) stage - Gametophyte – haploid (n) stage Plant Needs -Sunlight -Water and minerals -Gas Exchange -Movement/transport of water and nutrients

Overview of Plant Kingdom Gymnosperms Cone-bearing plants Ferns and their relatives Angiosperms Flowering plants Mosses and their relatives Flowers; Seeds Enclosed in Fruit Seeds Water-Conducting (Vascular) Tissue Green algae ancestor ^- thought to have arisen from multicellular green algae (a protist)

1. Bryophytes - Mosses Moss No vascular tissues FOUR MAIN GROUPS OF PLANTS… Moss 1. Bryophytes - Mosses No vascular tissues water transported by osmosis reproduction depends on water. Liverwort Hornwort

2. Ferns Have vascular tissues to transport water. Use spores to reproduce. Have roots, leaves, and stems.

Seed Plants Reproduction in flowers or cones 3. Gymnosperms (cones) naked seeds 4. Angiosperms (flowers) protected seeds Pollination: SEEDS – plant embryo surrounded by a protective covering Vascular tissue Pollen is male gametophyte (sperm)

Gymnosperms Needles – good adaptation…why? Seeds produced on cones Sequoia Cycad

Angiosperms Categorized by the number of seed leaves (cotyledons) Monocot: one cotyledon, Dicot: two cotyledons Monocots Dicots Single cotyledon Parallel veins Floral parts often in multiples of 3 Vascular bundles scattered throughout stem Fibrous roots Two cotyledons Branched veins Floral parts often in multiples of 4 or 5 Vascular bundles arranged in a ring Taproot Seeds Leaves Flowers Stems Roots

Angiosperms *Cool Fact: Angiosperms consist of 235,000 species; 90% of the Plant Kingdom Special adaptations: 1) Flowers: a) attract animals which helps them transport seeds and b) contain ovaries which surround and protect seeds 2) Fruit: Protects seeds and is a bribe to animals to eat and spread the seeds elsewhere

Vascular tissue Function is to transport water and nutrients throughout the plant. “Veins” are a gathering of vascular tissue consisting of: - XYLEM – carries water from roots upward to rest of the plant. - PHLOEM – transports nutrients to the rest of the plant Can transport against gravity

Vascular System

Plant Parts and Function 1) Roots – underground organs that absorb water and minerals, keep plant upright 2) Stems – support & transport structure connecting roots and leaves 3) Leaves – organ where photosynthesis takes place, has adjustable pores for gas exchange *All contain vascular tissue!

Roots Taproots – mainly in dicots, help plant reach waters far below surface. Fibrous roots – mainly in monocots – good at preventing erosion

2) Stems Functions: a) Produce leaves, branches and flowers b) Hold leaves up to sunlight c) Transport substances between roots and leaves buds

3) Leaves Functions: Photosynthesis Transpiration: Plant loses water through leaves Gas Exchange: Take in CO2 and release O2 during photosynthesis. Guard cells open and close in response to water pressure.

Leaf Structures Mesophyll: make up the bulk of most leaves, packed with chloroplasts and carry out nearly all the photosynthetic activity. Palisade mesophyll: just under the epidermis. They absorb much of the light that enters the leaf. Spongy mesophyll: beneath the palisade layer, with many air spaces. Xylem: transport water. Phloem: transport nutrients and products of photosynthesis.

Leaf Structures Stomata: pore-like openings in the underside of a leaf. Allow CO2 and O2 to diffuse in and out. Guard Cells: specialized cells in the epidermis that control the opening and closing of stomata. Each stoma has two guard cells.

Leaf Structure Cuticle Veins Epidermis Palisade mesophyll Xylem Phloem Spongy mesophyll Epidermis Stoma Guard cells

Water and nutrient transport in plants Capillary Action – water moves up wall of tube. Transpiration – when water evaporates out/off, pulling force is created to take in water. Root pressure – when soil moisture is high, water diffuses into roots

Flower Structure Stamen Carpel Stigma Anther Style Filament Ovary Petal Ovule Sepal

Seeds = fertilized zygotes (would become a new plant)

What did the male stamen say to the female pistol? I like your style!

Pollination Pollen (the male gamete) from the anther is released and transported to stigma of other flowers: By insects By mammals By birds By wind Ragweed pollen

Fruits and Seeds Ovule is fertilized, and grows to become seed, protected by seed coat Fruits are mature ovaries, to protect and disperse seeds.

Germination Plant emerging from seed (sprouting) Conditions need to be right… What do you think these conditions are? -temperature -water -oxygen (for aerobic respiration to occur…plant needs to obtain energy)

Patterns of Plant Growth Hormone-producing cells All plants follow a highly regulated pattern of growth that continues throughout the plant’s life. Plant hormones: chemical substances that control a plant’s patterns of growth and development, and the plant’s responses to environmental stimuli. Movement of hormone Target cells

Auxins and Phototropism Auxins: plant hormones produced in the apical meristem. They stimulate cell elongation (with higher amounts being produced in shaded areas). Auxins are also responsible for gravitropism. High concentration of auxin Low concentration of auxin Tip removed Opaque cap Clear cap Opaque shied over base Control

Cytokinins and Gibberellins Cytokinins: plant hormones that are produced in growing roots and in developing fruits and seeds. They stimulate cell division and the growth of lateral buds in plants, and cause dormant seeds to sprout. Gibberellins: plant hormones that cause an increase in the overall size of plants and individual plant structures.

Ethylene Ethylene: In response to auxins, fruit tissues release small amounts of the hormone ethylene. Ethylene then stimulates fruits to ripen.

Plant Responses (“Taxis” aka “tropisms” Phototropism: causes a plant to grow toward a light source. Gravitropism: causes the shoot of a germinating seed to grow out of the soil.

Plant Responses (cont.) Thigmotropism: the response of plants to touch. NASTIC RESPONSE Click ME!

Show lilly grown ppt