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Plant Structures
AP Biology
Unit 5
Extreme Plants!
• Deepest Root:
– fig tree in South Africa
– roots that extend 120 m (393.7 ft) into the
ground
• Tallest Tree:
– Sequoia tree in the Redwood National Park
(CA)
– 379 ft, 4 inches (in 2006)
• Oldest Tree
– Bristlecone pine cut down in Mt. Wheeler,
Nevada in 1963
– Estimated to be 5200 years old
Images taken without permission from http://www.gagfactory.com/photos/usa1999/part06/moreton_bay_fig_tree.jpg and
http://www.nps.gov/archive/seki/shrm_pic.htm
Extreme Plants!
• Largest leaf:
– raffia palm and Amazonian
bamboo
– can have leaves up to 65 ft in
length.
– Alocasia Macrorrhiza has the
longest undivided leaf
– 9 feet long, 6 feet wide
Images taken without permission from
http://images.google.com/imgres?imgurl=http://thelongestlistofthelongeststuffatthelongestdomainnameatlonglast.com/images3/leaf.JPG&imgrefurl=http://thelongestlistofthelo
ngeststuffatthelongestdomainnameatlonglast.com/long330.html&h=259&w=195&sz=12&hl=en&start=1&tbnid=1oWtKUiri7q7nM:&tbnh=112&tbnw=84&prev=/images%3F
q%3D%2522Amazonian%2Bbamboo%2522%26svnum%3D10%26hl%3Den%26lr%3D and http://www.raffiaonline.com/imgs/about-page/raffia-palm.jpg
Extreme Plants!
• Slowest growing tree:
– A white cedar in Canada
– has only grown to a height
of 4 inches and 0.6 oz over
the course of 155 years.
• Fastest Growing Plant:
– Some species of bamboo
– grow up to 3 ft in a day
Images taken without permission from http://www.ponnitai.com/database/thuja/occidentalis/europe_gold2.jpg andhttp://www.landoftheanxiousdog.com/images/bamboo.jpg
Roots
• The function of roots in a plant is to
– Anchor plant
– Absorb water and minerals
– Store organic nutrients (starch)
Types of Roots
• Types of roots include:
– Taproot
– Fibrous Root
– Adventitious Root
Taproot
• One main root
• Lateral roots (smaller side
roots) come off of main root
• Good for storage of organic
nutrients (starch)
• Ex. carrots, turnips
Img Src: http://collections.ic.gc.ca/gardens/New%20Bio%20Web%20Pix/OPTIMIZED%20BIO%20PLANT%20PARTS/3%20root%20systems.jpg
Fibrous Roots
• Lots of smaller roots (no
main root)
• Large surface area (good for
absorbing water and
nutrients)
• Clings to soil well– prevents
erosion (washing away)
• Ex. grass
Img Src: http://collections.ic.gc.ca/gardens/New%20Bio%20Web%20Pix/OPTIMIZED%20BIO%20PLANT%20PARTS/3%20root%20systems.jpg
Adventitious Root
• Roots that grow out of
plant parts above ground
(like the stem or the
leaves)
• Allows plants to reestablish selves even
after stem has been cut
off, lends support
• Ex. Corn, banyan trees,
some palms use them for
additional support
Img Src:
http://collections.ic.gc.ca/gardens/New%20Bio%20We
b%20Pix/OPTIMIZED%20BIO%20PLANT%20PART
S/3%20root%20systems.jpg
Root hairs
• Located just after the root
tips
• Tiny projections that
increase the surface area
on the root for water and
mineral absorption
Question…
• What kind of roots would a landscape
architect want to have in plants (s)he puts
on a steep hillside to prevent a landslide
from occurring
• Fibrous roots– holds the soil better, so there
won’t be erosion.
Parts of a Leaf
• A leaf consists of
– Blade
– Petiole
Img Src: http://www.yourdictionary.com/images/ahd/jpg/A4leaf.jpg
This whole
thing is a
leaf!
Parts of a Leaf
• The leaf is also where most photosynthesis
takes place
• Leaves can also be modified for support,
reproduction, protection and storage.
– Ex. Spines on a cactus, flower petals, onions
Parts of a leaf
Cuticle
Epidermis
Palisade
Mesophyll Cells
Bundle Sheath Cells
Xylem
Vein
Phloem
Cuticle
Epidermis
Spongy Mesophyll
Cells
Guard Cells
Stoma
Question…
• In which cells would the most
photosynthesis take place– palisade or
spongy mesophyll?
• Palisade mesophyll– because they are at the
top, they have the most access to sunlight.
Plant Tissues
• 3 types
• Dermal Tissue
– Outer covering of the plant
– Includes epidermis, cuticle,
guard cells
• Vascular Tissue
– All transport systems (xylem and
phloem)
• Ground Tissue
– Everything else in the plant
– Storage, support, photosynthesis
Plant Cell Organelles
• Chloroplast
– Site of photosynthesis
• Mitochondria (also present in animal cells)
– Site of cellular respiration
• Tonoplast
– For water storage
• Leucoplast
– For starch storage
Plant Cells- Transport
• Water-conducting cells
(Make up the xylem)
• Sugar-conducting cells
(Make up the Phloem)