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 Humboldt Redlands State Park (CA) –370 ft (in 2004) Images taken without permission from and

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 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

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 andhttp://

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:

Fibrous Roots Lots of smaller roots (no main root) Large surface area (good for absorbing water and nutrients) Clings to soil well– prevents erosion Ex. grass Img Src:

Adventitious Root Roots that grow out of plant parts above ground (like the stem or the leaves) Allows plants to re- establish selves even after stem has been cut off, lends support Ex. Corn, banyan trees, some palms use them for additional support Img Src: 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 This whole thing is a leaf! Img Src:

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

Parts of a leaf Palisade Mesophyll Cells Bundle Sheath Cells Xylem Phloem Epidermis Spongy Mesophyll Cells Guard Cells Stoma Cuticle Vein

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 –Site of cellular respiration Tonoplast –For water storage Leucoplast –For starch storage

Plant Cells- Parenchyma Thin walls Most abundant cells in young plants Usually photosynthetic cells Other nonphotosynthetic cells are for starch or lipid storage

Plant Cells- Collenchyma Supporting cells– when living Thicker walls than parenchyma Flexible and elongated Ex. Collenchyma cells in the petioles allow them to sway in the wind without breaking Ex. “Strings” in celery are also made up of collenchyma

Plant Cells- Sclerenchyma Supporting cells– when dead Have thickened walls Ex. Cells in bark of trees, cells that make up the xylem

Plant Cells- Transport Water-conducting cells (Make up the xylem) Sugar-conducting cells (Make up the Phloem)