BotanyThe Study of Plants

Kingdom Plantae

• General Characteristics

Contain Chlorophyll a

Multicellular

Made up of Eukaryotic Cells

Photosynthetic Autotrophs

Cell Walls made of Cellulose (polysaccharide)

Produce sugars as glucose, transport sugars as sucrose and store sugars as starch. (polysaccharide)

Adaptations plants made to survive on land

• Developed Cuticles – waxy, protective outer coverings which prevent water loss.

• Developed spores/seeds for reproduction.

• Developed vascular tissues for transportation of water and sugars.

• Developed tissues to strengthen stems to overcome gravity.

The Classification of Plants Plants can be classified as Bryophytes or Tracheophytes.

Bryophytes are described as plants that lack xylem and phloem. (vascular tissue)

Xylem is a type of vascular tissue that transports water upward from the roots to the leaves. Phloem is a type of vascular tissue that transports sugars (nutrients) from the leaves downward

Tracheophytes are plants that have xylem and phloem. (vascular tissue)

The Bryophytes are

Moss

The Tracheophytes are divide into five groups….

The largest of the five groups are the:

Non-Seed Bearing Plants

And

Seed Bearing Plants

The Non-Seed Bearing Tracheopytes are:

Ferns(They reproduce using spores)

The Seed Bearing Plants are divided into two

groups:

Gymnosperms (naked-seed Plants)

and

Angiosperms (encased-seed plants)

Seed Plant Life Cycle

The Gymnosperms are:

Cycads – palm-like plants

Ginkgoes – only one species remains, Ginkgo biloba

Conifers – “cone-bearing” plants… pines, firs, redwoods, etc……..

The Angiosperms are theFlowering Plants.

• Angiosperms are divided into two groups:

Monocotyledons (Monocots)

And

Dicotyledons (Dicots)

4 Differences betweenMonocots and Dicots

Monocots DicotsLeaves - venation is Parallel venation is nettted

Petals - multiples of 3 multiples of 4 or 5

Seeds - one cotyledon two cotyledons

Vascular tissues in a monocot stem are arranged randomly as look like “Monkey” faces.

Vascular tissues in a dicot stem are arranged in a ring surrounding the pith.

Monocots Dicots

Leaves - venation is Parallel venation is nettted

Venation of Leaves

Number of Petals

Monocots Dicots multiples of 3 multiples of 4 or 5

Seasonal Adaptations

• Evergreens – plants that remain green year round…. Pine trees.

• Deciduous – plants that lose all their leaves once a year…. Apple trees,

grapes.

Short and Long Day Plants

• Short-day Plants – Flower when the days are shorter than 12 hours… onions, garlic. Chrysanthemum: a Short-Day Plant

• Long-day Plants - Flower when the days are longer than 12 hours… tomatoes, beans.

Growth Cycles(from seed to seed)

• Annuals – complete their entire life cycle in one growing season. Example: mums

• Biennials – complete their entire life cycle in two growing seasons. Example: Broccoli

• Perennials – continue to grow year after year…. Example: Apple trees live for 80 years.

Stem Types

Herbaceous – Green, soft….will wilt is water

loss is extreme…. Sour grass, celery.

• Woody - Brown, rigid…. Will remain erect even after they are dead….

trees

Review of PhotosynthesisPhotosynthesis is the process by which plants use the energy

of sunlight to combine carbon dioxide and water to form glucose and oxygen.

Light Energy + 6CO2 + 6H20 C6H12O6 + 6O2

Reactants Products

Factors which Affect Photosynthesis

• Amount of available Sunlight

• Amount of available Water (rainfall)

• Amount of Carbon Dioxide

• Optimal Temperatures

Tropisms are the responses plants have to stimuli.

A Negative (-) response is “away” from the stimuli

A Positive (+) response is “toward” to stimuli

Phototropism – a plant’s response to light

Gravitropism – a plant’s response to gravity

Hyrdotropism – a plant’s response to water

Chemotropism – a plant’s response to chemicals

Thigmotropism – a plant’s response to touch

Phototropism a plant’s response to light

Gravitropism - (also called Geotropism) a plant’s response to gravity

A Corn Root responds positively to gravity

Thigmotropism a plant’s response to touch…the tendrils of a

bean plant wraps around a garden post.

Plant Hormones

• Cytokinins – promote cell division, promotes the germination of dormant seeds.

• Auxins – promote cell elongation in stems and inhibit elongation in root cells.

• Gibberillins – promotes “bolting” (sudden growth) and cessation of dormancy.

The Bryophytes

Moss• Reproduce by Spores (haploid reproductive cells)

• Lack Xylem and Phloem• Size limited by lack of Vascular tissue.• Reproduce through Alternation of Generations…..

the Two Generations are the Gametophyte Generation (n) which produces the gametes, and the

Sporophyte Generation (2n) which produces the spores.

The Life Cycle of Moss

The Life Cycle of Moss

Gametophyte Generation (n)Gametophyte Generation (n)

The Life Cycle of MossSporophyte Generation (2n)Sporophyte Generation (2n)

The Life Cycle of Moss

The Tracheophytes

FernsReproduce by Spores (haploid reproductive cells)

• Reproduce through Alternation of Generations.

• Have Xylem and Phloem for transportation

The Life Cycle of a Fern

The Life Cycle of a Fern

(n)

¼”

Gametophyte Generation (n)

The Life Cycle of a Fern

Fronds

Rhizome (contains Xylem and Phloem)

Sporophyte Generation (2n)

The Life Cycle of a FernUnderneath the leaflets of the

fronds are the Sori (sorus sng.)

The Sori are made up of the Sporangia

The Sporangia are the Spore-producing

structures.

The Life Cycle of a Fern