plant biology - systems

Systems: Roots and ShootsPlant Parts: root, stem, leaf, flowerPlant Biology Part 1 -

Systems

Plant Body Systems

Two types of systems:Root SystemShoot System: stem, leaf, flower

Plant organs: root, stem, leaf, flower referred to as plant parts

Root System Function Anchorage

Keeps plant in the soil

Prevents soil erosion Holds stem in place

Absorption water dissolved minerals

Storage Starch Other nutrients

Types of Rootshttp://www.bio.miami.edu/dana/pix/taproot_fibrousroot.jpg

http://tchefty.wikispaces.com/file/view/rootsystems1.jpg/260637884/rootsystems1.jpghttp://kentsimmons.uwinnipeg.ca/2153/rootsystems1.jpg

Taproot

Large long primary root Penetrate deep into the ground Small thin roots grow laterally off main

root Strong anchoring system Examples: evergreen trees

Taproot

Specialized to store water, food, nutrients

Better chance at drought survival

Examples: carrot, beet, turnip, radish

http://www.ontarioweeds.com/media/jpg/tropr_root.jpg

Fibrous Root

Many small roots that branch

Increases surface areaBetter absorption of water

and mineralsLess structural supportExamples: peas, beans,

lettuce

Root Hairs Small fibrous

objects that branch off roots

Absorbs water and minerals

Root ZonesZone of maturation:

cells differentiate into different types of cells

Zone of elongation: allows the root to get deeper within the soil

Meristematic region: rapid mitosis of undifferentiated meristematic cells

Root cap: protects the meristematic region

Shoot System

Stem – structure and transportLeaf – photosynthesis Flower – reproduction

Stem

Raises and supports branches, leaves and flowers

Transport of water and nutrients

In trees the main stem is the tree trunk

http://www.pxleyes.com/images/contests/bw%20tree%20trunks/fullsize/bw%20tree%20trunks_4b6283790291c.jpg

Stem

Young green stems can perform photosynthesis because they have chloroplast in their epidermal cells

StemSome are specialized for food storageExamples: sugar cane, potatoes

http://upload.wikimedia.org/wikipedia/commons/9/96/Sugar_Cane.jpg

4 Types of Modified Stem

StolonRhizome

TuberBulb

Modified Stem: Stolon Grow on surface of ground

horizontally Enable plant to colonize

large areas asexually from a single parent

Example: Strawberry runners

http://plant-passion.typepad.com/.a/6a00e551cf6c9a88330120a5344f62970b-pihttp://strawberryplants.org/wp-content/uploads/2010/05/strawberry-plant-runners.jpg

Modified Stem: Rhizome

Horizontal growth underground (an underground stolon)

Example: Edible base of ginger planthttp://nogmoseedbank.files.wordpress.com/2010/10/zingiberofficinale-thum.gif

Modified Stem: Tuber Swollen ends of

rhizomes specialized for food storage

Example: potato, yam, taro, cassava, sweet potato

http://database.prota.org/dbtw-wpd/protabase/Photfile%20Images/Adenia%20digitata%20tuber%20B.%20Wursten.jpg

Adenia digitata is poisonous. The Tswana people of Botswana have used the fruit for homicide. Accidental poisoning mainly occurs when the root of Adenia digitata is mistaken for edible tubers. To treat skin ailment, leprosy or ulcers, the Nyanja people of Malawi and Zambia rub the skin with boiled roots or a root decoction.

Modified Stem: Bulb

Vertical underground swollen base Example: Onion bulb

http://4.bp.blogspot.com/-YTxeUV00GQI/TbFydVLx6WI/AAAAAAAAB7Q/_Ae2T2c1ico/s1600/spring_onionR.jpghttp://69.39.232.84/~ecofrien/oniongardening.com/wp-content/uploads/2007/02/harvestonions.jpg

LeafMain function: Photosynthesis Parts of the Leaf:

Cuticle Epidermis Guard Cells & Stoma Palisade cells Spongy Layer Vascular Tissue

Epidermis Outer layer

of cells Leaf

epidermis produces cuticle

http://www.goldiesroom.org/Multimedia/Bio_Images/05%20Nutrition/15a%20Cross%20Section%20of%20a%20Leaf.jpg

Cuticle Waxy

substance that coats the exterior

Water proofing

Protect interior tissues

Blocks passage of gases

http://www.goldiesroom.org/Multimedia/Bio_Images/05%20Nutrition/15a%20Cross%20Section%20of%20a%20Leaf.jpg

Guard Cells & Stoma Stoma (Greek for

“mouth”) Pore-like openings in the

plant’s epidermis Opening size controlled

by two guard cells permits gas exchange

between the leaf’s interior and external environment.

larger opening, faster gas exchange

Guard Cells & Stoma

Spongy Layer

Where water is stored

Where the vascular tissues reside

Palisade Cells Contains many

chloroplast for photosynthesis

Cells stand tall and upright Top end

exposed to light Bottom end

exposed to the gases in the spongy layer

Chloroplast Structure Thylakoids are flat

disc-like structures where chlorophyll is embedded

Grana are thylakoids arranged in a stack

Chlorophyll is a pigment that captures light energy

Site for starch (a type of sugar) storage

Site for photosynthesisReaction involves

trapping light energy to create food in the form of sugars

Starting substances are carbon dioxide and water

CO2 + H2O + energy O2 + glucose

Chloroplast Function

Leaf Cross Section Scanning electron microscope image

of a leaf from a Black Walnut tree. (Dartmouth Electron Microscope Facility/Dartmouth College)

http://cache.boston.com/universal/site_graphics/blogs/bigpicture/micro_11_14/m04_walnut_leaf.jpg

Modified Leaf: Cactus

Poinsettia Leaves

Flower

Specialized structures developed for sexual reproduction known as pollination

Can contain both male and female reproductive structures in the same flower

Flower PartsMale reproductive organ: stamenFemale reproductive organ: pistil

http://www.exploringnature.org/graphics/teaching_aids/flower_parts_color72.jpg

Flower Parts Male gametes: pollen grains found on anther Female gametes: ovule housed in ovary

Pollination Act of sexual reproduction in plants Pollen reach stigma, travel down the

style into the ovary to fertilize the ovule

Pollen grains blown by wind

Plants are often small and drab but produce a large amount of pollen

Example: grass

Methods of Pollination: Wind

http://www.vcbio.science.ru.nl/images/pollen/pollen-grass-stigma.jpg

Methods of Pollination: Wind

All conifers are non-flowering

Produce male and female pine cones

Use wind to pollinate

http://www.sciencephoto.com/media/17620/enlarge

Methods of Pollination: Animals

Insects, birds, bats

Insects pollinate about 70% of all flowering plants

Crops pollinated by bees provide 30% of human food

Attracting Pollinatorsnectar

http://4.bp.blogspot.com/_Xla0E3fwLto/S4CL_NstZuI/AAAAAAAABP4/PgoWyz-Mk2w/s400/4342259001_e10572466d_b.jpg

Attracting Pollinators

Fragrant flowers (scent)Big Pollen Load

http://guelph.ca/uploads/Healthy%20Landscapes/Pollination_Bee_Dandelion_Zoom.jpg

Attracting Pollinators Large Stigma

Attracting Pollinators

Large Petals

Attracting Pollinators Bright colours

Attracting Pollinators Pollen

guides/indicator

Pollination videos (BBC David Attenborough)Titan Arum’s scent (2:29)

http://www.youtube.com/watch?v=FHaWu2rcP94&feature=related

Hoverfly and pollen guides (2:29)

http://www.youtube.com/watch?v=MQlq5QtRI9o

Orchid mimics female wasps (2:59) http://www.youtube.com/watch?v=-h8I3cqpgnA

After Pollination

Zygote (fertilized egg) becomes the seed

Ovary becomes the fruit

After Pollination

Zygote (fertilized egg) becomes the seed

Ovary becomes the fruit

http://www.biosci.ohio-state.edu/~plantbio/osu_pcmb/pcmb_lab_resources/images/pcmb101/flwrs_sds_frts/where_fruit.jpg

After Pollination

http://greatneck.k12.ny.us/gnps/shs/dept/science/krauz/bio_h/images/38_09FruitDevelopment_L.jpg