Kingdom: Plantae

What is a plant?

• Multicellular• Eukaryotic• Cell wall made of cellulose• Develop from multicellular embryos• Carry out photosynthesis• Contain chlorophyll a and b to trap

sunlight.

Life Cycle of Plants• Plant life cycles have

2 alternating phases, a diploid (2n) and a haploid (n) phase, known as alternation of generations.

HaploidDiploid MEIOSIS

Spores(N)

Sporophyte Plant (2N)

Gametophyte Plant (N)

FERTILIZATION

Sperm(N)

Eggs(N)

What plants need to survive?

• Sunlight• Water and minerals• Gas exchange (stomata)• Transport of water and nutrients (xylem

and phloem)

Groups of Bryophytes

• This group lacks vascular tissue therefore it uses diffusion and osmosis to obtain nutrients.

• Mosses Which do not have true roots instead have rhizoids.

• Liverworts• Hornworts

Seedless Vascular Plants

Comparing Spore-Bearing Vascular Plants

CharacteristicsWatertransportation

Structure

Club MossesBy vasculartissue

Look like miniature pine trees; scalelike leaves

HorsetailsBy vasculartissue

True leaves, stems, and roots

FernsBy vasculartissue

Creeping or underground rhizomes (stems); fronts (leaves); some have no roots or leaves

Seed PlantsComparing Features of Seed Plants

FeatureSeeds

Reproduction

Examples

Gymnosperms Angiosperms

Bear their seeds on cones

Can reproduce without water; male gametophytes are contained in pollen grains; fertilization occurs by pollination

Conifers, cycads, ginkgoes, gnetophytes

Bear their seeds within flowers

Can reproduce without water; male gametophytes are contained in pollen grains; fertilization occurs by pollination

Grasses, flowering trees and shrubs, wildflowers, cultivated flowers

are categorized as

that completetheir life cycle in

that completetheir life cycle in

that completetheir life cycle in

Concept Map

Plants

Annuals Biennials Perennials

1 growingseason 2 years

More than2 years

Monocots Dicots

Seeds

Leaves

Flowers

Stems

Roots

Single cotyledon

Parallel veins

Floral parts often in multiples of 3

Vascularbundlesscattered throughout stem

Fibrous roots

Two cotyledons

Branched veins

Floral parts often in multiplesof 4 or 5

Vascularbundlesarranged ina ring

Taproot

Comparison ofMonocots and Dicots

Seed Plant Structures

include

includes includes includes

includes includes

Plant Tissues

Dermaltissue

Meristematictissue

Vasculartissue

Groundtissue

Epidermalcells Xylem Phloem Parenchyma

cellsCollenchyma

cellsSchlerenchyma

cells

Tracheids Vesselelements

Sieve tubeelements

Companioncells

Plant Tissue Systems• Dermal Tissue: consists of epidermal cells that

cover the outer surface.• Vascular Tissue: specialized transport cells1. Xylem: carries water and nutrients up from the

roots. (tracheids and vessel elements)2. Phloem: carries sugars down from leaves

(sieve tube elements and companion cells)• Ground Tissue: contains photosynthesizing

cells and cells that help make plants strong.

Plant Growth

• Meristems are clusters of cells at the tips of roots and stems that are responsible for the growth throughout a plant’s life.

• The new cells produced are called meristematic tissue.

• Apical meristems are located at the tip or end of the root and stem that produces new cells by the process of mitosis.

RootsEpidermis

Ground tissue(cortex)

VascularCylinder

Cross Section of Plant Root(magnification: 40x)

Ground tissue (cortex)

Epidermis

EndodermisVascular cylinder

Root hairs

Phloem

Xylem

Apical meristem

Root cap

Zone of maturation

Zone of elongation

Endodermis

Function and Types of Roots• The roots job is absorb water and

nutrients form the soil and anchor the plant in the ground.

• Types:1. Taproot a long root that extends deep

into the ground.2. Fibrous root: branching root help prevent

topsoil erosion.3. Some plants have both types of roots.

Leaf Structure

Veins

XylemPhloem

Vein

Cuticle

Epidermis

Palisademesophyll

Epidermis

Stoma

Guardcells

Spongymesophyll

Leaf Function

• Stomata: gas exchange• Guard cells: open and close the stomata• Mesophyll: contain cells that carry out

photosynthesis.

Transpiration• The pull of water

from the roots to the leaves of the plant

Factors that increase transpiration:

1. Increase temperature

2. Increase wind3. Decreased humidity

Sugar Movement in Plants

Movementof water

Movementof sugar

Sugarmolecules

Source cell

Sink cell

Phloem Xylem

Reproduction with Cones

Reproduction with Flowers

FilamentAnther

StigmaStyle

Ovary

Carpel

PetalSepalOvule

Stamen

Stamens: the male portionOf the flower1. anther: produces pollen2. filament

Carpel (Pistil): female Portion of the flower.1. ovary: contains the ovules.2. stigma: sticky tip that pollen attaches to.3. style: creates the Pollen tube that allowsPollen to reach the eggs.

Haploid (N)

Diploid (2N)

MEIOSIS

FERTILIZATION

Cycle of an Angiosperm

Ovule

Anther (2N) Pollen grains (N)(male gametophyte)

Pollentubes

Haploid cell(N)

Embryo sac (N)(female gametophyte)

Egg cellSperm

Pollen tubeEndosperm nuclei

Endosperm(3N)

Zygote(2N)FruitSeed coat

Endosperm

Embryo(2N)Seedling (2N)

(new sporophyte)

Maturesporophyte

Ovary

Style

Stigma

Comparing Wind-pollinated and Animal-pollinated Plants

CharacteristicsPollination method

Relative efficiency of pollination method

Plant types

Reproductive organs

Adaptations that promote pollination

Wind-pollinatedPlantsWind pollination

Less efficient

Mostly gymnosperms and some angiosperms

Cones

Pollination drop

Animal-pollinated PlantsVector pollination

More efficient

Angiosperms

Flowers

Bright colors, sweet nectar

Wind vs. Animal Pollination

Seed Dispersal

• Animals: sweet, fleshy fruits (blueberries) • Wind and water: lightweight, allowing them

to be carried by air or float in water. (tumbleweeds)

Seed Germination

Plant Hormones• Chemical substances that control a plant’s

patterns of growth and development, and the plant’s responses to environmental conditions.

• Auxin: stimulate cell elongation• Gibberellins: increase size of stems and

fruit• Cytokinins: stimulate cellular division • Ethylene: Stimulate the ripening of fruit.

Auxin and phototropism

Control Tipremoved

Opaquecap

Clearcap

Opaque shiedover base

Highconcentration

of auxin

Lowconcentration

of auxin

Auxin production of the shaded side of plant causes it to Bend towards the light.

Auxin and Gravitropism

Auxin causes stems to grow up and roots to grow down in Response to gravity.

Apical meristem

Lateral buds

Apical meristem removed

Auxins produced in the apical meristeminhibit the growth of lateral buds.

Without the inhibiting effect of auxinsfrom the apicial meristem, lateral budsproduce many branches.

Auxin and Branching Apical Dominance

Auxin-like Weed Killers

• High concentrations of auxins inhibit plant growth.

• Scientists have engineered herbicides like 2,4-D that mimic the hormone auxin and thus kill weeds.

Plant Reponses

• Phototropism: response to light• Gravitropism: response to gravity• Thigmotropism: response to touch

PhotoperiodismMidnight

NoonLong Day

Midnight

NoonShort Day

Midnight

NoonInterrupted Night

Short-Day Plant Long-Day Plant

Photoperiodism:Is reponsible for The timing ofSeasonalActivities such asFlowering and growth

The response To flowering Is controlled byThe amountOf darkness thePlant receives

Winter Dormancy

• As cold weather approaches, deciduous plants turn off photosynthetic pathways, transport materials from leaves to roots, and seal off leaves from the rest of the plant.

Adaptations

• Chemical defenses: manufacture compounds that have a powerful effect on animals. Ex. Aspirin, tobacco

• Epiphytes: Grow on trees to reach sunlight.

• Succulents: reduces leaves, extensive roots, thick stems. (cacti)

• Carnivorous Plants: digest insects.