Background Image http://www.respect-texas.org/bluebonnets.jpg
Plant Systems
The Texas Bluebonnet (Lupinus texensis) is our state flower and a plant native to Texas.
Remember that plants are NOT dead, but very much alive and composed of eukaryotic cells!
In this unit we will discuss the systems in plants, specifically transport, reproduction, and response.
Review of Plant CellsPlants are multicellular
eukaryotes w/ cell walls made of cellulose.
Plants are autotrophs that carryout photosynthesis to obtain energy.
To carry out cellular functions, plants need: – Sunlight– Water– CO2– Minerals
http://www.terrebonneonline.com/plantcell1.jpg
Review of Photosynthesis6CO2 + 6H20 + LIGHT C6H1206 +
602 (Carbon dioxide) (water) (glucose)
(oxygen)
Photosynthesis – the process by which plants convert light energy and carbon dioxide into sugars as a food source for the plant.
http://s2.hubimg.com/u/701793_f520.jpg
The Second Part of PhotosynthesisCalvin Cycle or Light Independent Reaction• Also called Carbon Fixation or C3 Pathway• Uses energy (ATP and NADPH) from light reaction to make sugar (glucose).• Occurs in the Thylakoid membranes
Cell Specialization
Plants have cell specialization (different cell types perform specific functions).
EX Root cells, stem cells, and flower petal cells all have specific functions (jobs) that they carry out for the plant.
http://www.bio.txstate.edu/~wetlands/Kids_and_Teens_Page/parts%20of%20a%20plant.jpg
3 TYPES OF PLANT TISSUES
DERMAL – PROTECTION FOR THE PLANT (WAXY COATING)
VASCULAR – TRANSPORT FOOD & WATER
GROUND TISSUE – Cells that lie between dermal and vascular tissue make up the ground tissue.– CONTAINS CELLS THAT ARE THE
SITE OF PHOTOSYNTHESIS
Veins in a plant are called VASCULAR TISSUE
There are 2 types of Vascular Tissue:1. Xylem – transports water
from roots to the rest of the plant
2. Phloem – transports sugars and other nutrients throughout a plant (FOOD)
MERISTEMATIC TISSUEUndifferentiated – has
not yet become specialized
These cells are produced in the apical meristems (tips of roots & stems)
Meristematic tissue is the only plant tissue that produces new cells by mitosis!
Specialized Tissues - Leaves
Leaf is the organ where most photosynthesis, and transpiration [evaporation from plants] occurs.
Remember, photosynthesis is used by plants to create energy.
Through the leaf run veins transport water, sugars, and minerals to the plant cells.
http://www.ecomagic.org/fruition/leaves-1.jpg
LeavesStomata are pores or holes in
the epidermis of the leaf that allow gas exchange (stoma – singular)
Carbon dioxide comes in through the stomata and oxygen leaves through the stomata
Guard cells on each side of the stomata control its opening and closing
Water is also lost through the stomata in a process called transpiration, so plants only leave stomata open long enough to do photosynthesis
When water pressure within the guard cells is high (lots of water inside of plant) the thick outer walls of the cells are forced into a curved shape, which opens the stoma.
When water pressure within the guard cells is low the inner walls pull together and close the stoma.
Stoma & Guard Cells
Specialized Tissues - StemsStems are specialized
cells that support leaves to hold them up to sun and transport water, sugars, and nutrients through the plant.
Some stems are also modified for sugar [glucose] storage areas.
http://www.arboretum.fullerton.edu/grow/images/plant_organs.jpg
In most plants, stems contain distinct nodes, where leaves are attached, and internodes regions between the nodes.
Monocot – scattered vascular bundles
Dicot – vascular bundles arranged in a ring
Secondary Growth of StemsTakes place in lateral
meristematic tissues called–Vascular cambium – produces vascular tissues and increases stems thickness (wood)
–Cork cambium – makes the outer covering (bark)
Specialized Tissues - RootsRoots are underground organs that absorb
water and minerals necessary for transport in the plant and anchor [hold] the plant in the soil.
They help to prevent soil erosion.
http://www.kidsgardening.com/onlinecourse/Diagrams/c5/c5-1root.gif
PARTS OF A PLANTROOTS – ABSORB WATER
AND NUTRIENTS AND ANCHOR THE PLANT TO THE GROUND
TWO TYPES OF ROOTS:– FIBROUS (Clump of
short, threadlike roots)
– TAPROOT (Single, large central root)
Just like in animals, vascular [vein] tissue is the transport system for the plant.
Xylem – transports water (W X Y Z for w=water, xy=spelling xylem and z=the way the word sounds) in stacked cells to form tube like drinking straws; movement is UP from roots to leaves
Phloem – transports sugar/food; movement can be up and down
Transport Tissues
http://3.bp.blogspot.com/_b8o0_bDa4QI/RsKvBY5ZufI/AAAAAAAAAF0/BmCafNOYe6A/s400/xylem1%5B1%5D.gif
Alternation of Generations–Diploid
(2n)–Haploid
(1n)
Reproductive Tissues - Flowers
Flowers are a reproductive organ (but not all plants have flowers).
They have male and female parts. – pollination – transporting
pollen (sperm) from the male to female parts (ovule)
– fertilization – union of sperm with egg (creates a plant embryo [seed] which grows into a mature plant).
http://www.prairiefrontier.com/pages/families/flwrparts.jpg
Flower PartsMale
– Stamen – consist of the anther (produces pollen) and filament (supports anther)
– Pollen – contains spermFemale
– Pistil – consist of the stigma (where pollen lands), style (connects stigma to ovary) and the ovule (develops into the fruit)
– Ovule – develops into an egg, eventually becomes the seeds when fertilized
Non-sexual– Petals – colored parts, attract pollinators (EX bees)– Sepals – green parts, protect flower parts
Flower Parts Cont.
http://www.microscopy-uk.org.uk/mag/artoct08/bj-peru.html
Reproductive Tissues - Seeds
A seed consists of an embryo surrounded by a food source.
Seeds are encased in a protective covering called a seed coat.
EX fleshy fruit such as strawberries, apple, tomato, peach, cucumber
EX dry fruit such as walnuts and acorns
http://asm.wku.edu/courses/Biol115/Wyatt/Plants/seeds/seed.gif
http://urbanext.illinois.edu/gpe/images_rev/seed-pics.jpg
Seedless Reproduction
Seedless plants do not form hard seeds (EX mosses and ferns) they produce spores and therefore MUST have water for the sperm to swim to the egg.
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http://biology.uwsp.edu/courses/plantid/cp-seedless/images/cp-seedless-images-sm/013-d.lg.sm.jpg
Response Just like animals, plants respond to changes in
their environments (called tropism). There are four main types of tropisms:
– Gravitropism/Geotropism = response in plants that make it grow either with the pull of gravity or against it
– Hydrotropism = response in plants that bends it towards water
– Phototropism = response in plants that bends it towards light
– Thigmotropism = response in plants that bends it around an object (EX a vine wrapping around an arbor)
Response Cont.
http://withfriendship.com/images/h/38808/Tropism-picture.gif
Response Cont.Another type of
response, specifically to changes in pressure, is called a nastic response.
The most common example is the infamous Venus flytrap which closes its leaf when the plant senses an insect through changes in cell pressure.
North Carolina’s Nastic Slideshow
http://www.justvenusflytraps.com/images/homepageimage.jpg
PLANT KINGDOM
Conclusion
Plants provide consumers with oxygen to breathe, food, shelter, as well as cleaning the air and water for the planet. This photo was taken in the Scottish Highlands.
Just like animals, plants are active responders within various environments to survive and thrive.
Their use and importance is numerous; humans use plants with healing properties in medical treatments.
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