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Welcome to Northwest Plants. Northwest Indian College. ENVS 201 Spring Quarter 2012. Plant Parts. reproductive components:. vegetative organs:. flowers. stems. fruits. roots. seeds. leaves. Today: Roots. bean seedling ( Phaseolus ) showing root system. Root Features & Functions. - PowerPoint PPT Presentation
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ENVS 201 Spring Quarter 2012
Northwest Indian College
Welcome to Northwest Plants
Plant Parts
stems
roots
leaves
flowers
fruits
seeds
vegetative organs:
reproductive components:
Today:Roots
bean seedling (Phaseolus) showing root system
Root Features & Functions
anchor plants to substrate (e.g., soil)
water and nutrient uptake
may be variously modified (e.g., adventitious roots, food storage, etc.)
interactions with soil, microorganisms (in root nodules) and fungi (mycorrhizae)
adventitious roots (in Coleus)
roots modified for food storage
Beet (Beta)
sweet potato (Ipomoea)
Carrot (Daucus)
mycorrhizal root
hogpeanut (Amphicarpaea bracteata) with root nodules
root cells of pea (Pisum) in root nodules (infected with Rhizobium)
bacterium—>
root cell—>
Root Features
primary root - the main root of the root system
secondary root - a branch root
rootlet - a small root
root nodule - swelling produced by bacteria (e.g., in legumes), site of nitrogen-fixing bacteria (Rhizobium)
Root Types
taproot system (common in eudicots, e.g., dandelion, burdock & carrot)fibrous root system (monocots, e.g., grasses, and some eudicots)adventitious roots (e.g., Coleus)
taproots of burdock (Arctium) & dandelion
(Taraxacum)
Root Regions
root apical meristem - produces cells that lengthen roots
root hair - outgrowth of outer cell of root, extends absorbing region of root
root tip - tip (apex) of a young root
root cap - mass of cells at root tip, protective & maintains downward growth
root lateral meristem (vascular cambium) - produces cells that thicken roots, vascular tissues
root l.s. showing root tip<—apical
meristem
<—root cap
root tip
root hairs (in grass seedling)
basswood (Tilia) lateral meristem (vascular cambium)
vascular—> cambium
Questions & Comments?
Rootsarecool.
Hy’shqe!