Plant Systems & Organization 10B

Specialized Cells Guard Cells Stomata

Guard Cells – open and close the stomata (in epidermis in leaves)

Stomata - opening in epidermis that allows CO2 in and H2O & O2 out

Tissues Dermal Ground Vascular

Dermal Tissue Structure: Epidermis -outer layer, cuticle, root hairs Periderm - inner layer

Dermal Tissue Function: Protection Prevention of water loss

Ground Tissue Structure: Parenchyma - controls photosynthesis Collenchyma – support function in plants Sclerenchyma – support and hardening of plant(structure)

Ground Tissue

Function: Photosynthesis food storage regeneration support protection

Vascular Tissue Structure: Xylem Phloem

Vascular Tissue Function: transport of water and minerals up from roots transport of food (glucose) from leaves to other parts of plant

Response Systems - Tropisms - Plants respond to environment (grow towards or away from external stimulus) by hormones called auxins 3 types: Gravitropism Phototropism Thigmotropism

Auxins Plant hormone that responds to light, gravity, water, and seasonal weather changes

Gravitropism Stems grow up (against gravity), roots grow down (with gravity)

If a plant falls over, auxin accumulates in cells on the lower side of the stem. The stem will respond by growing upward.

Phototropism Plant grows towards light

Auxin accumulated where light is less intense and causes cells to elongate. As a result, the cells that receive less light grow longer than cells that receive more light. In a stem, this growth pattern causes the stem to bend toward the light source.

Thigmotropism Plant respond to touch

Types of Plants Bryophytes Sporophytes Gymnosperms Angiosperms

Bryophytes

Ex: Mosses, liverworts, hornworts Seedless plants that have no vascular tissue Transport water from cell to cell using osmosis & must live in moist or wet environments Usually small in size

Bryophyte Reproduction

Sporophytes

Ex: Ferns Seedless vascular plants Produce spores which in turn produce gametophytes Must be in wet environment so the sperm can fertilize the egg

Sporophyte Reproduction

Gymnosperms

Cone-bearing, vascular plants Ex: pine trees, palms Do not produce flowers but do produce seeds Do not require wet condition for reproduction Sperm is transferred by wind, insects, or animals

Gymnosperm Reproduction

Angiosperms

Vascular, seed producing plants Ex: flower producing plants, lilies, fruit trees Produce their seeds within a layer of tissue that protects the seed Flowers contain ovaries which protect the seeds Flowers attract pollinators Ovary of flower develops into fruit after fertilization

Angiosperm Reproduction