Please enable JavaScript.
Coggle requires JavaScript to display documents.
Roots (Other Types of Roots & Root Modification (Mycorrihizae…
Roots
Other Types of Roots & Root Modification
Storage Roots
provide long term storage of carbohydrates
Prop Roots
capable of extensive growth through the air
Contractile Roots
uppermost portion contracts
Haustorial Roots of Parasitic Flowering Plants
Roots of Strangler Figs
Aerial Roots of Orchids
spread along surface of bark
often dangle freely
Mycorrihizae
symbiotic relationship with fungi
ectomycorrhizal realtionship
fungal hypae penetrate between outtermost root cortex
endomycorrihizal association
hyphae penetrate the root cortex as far as the endodermis
Root Nodules
Nitrogen Fixation
Internal Structure of Roots
Root Cap
#
Root Apical Meristem
quiscent center
mitotically inactive central region
cells more resistant to harmful agents
more orderly root
Zone of Maturation
Root hairs grow outward
increases absorption
endodermis
cylinder inner layer of cortical cells
tangetial walls
closest to the vascular tissue or cortex
radial walls
top, bottom, and side walls
encrusted w/ lignin and suberin, making waterproof
Casparian strips
#
#
involved in controlling the types of minerals that enter water stream
bands of altered walls
Mature Portions of the Root
passage cells
cells that have only Casparian Strips
root pressure
powerful absorption and build of water pressure
Zone of Elongation
cells expand greatly
section behind Apical Meristem
differentiation of cells
Protoderm differentiate into epidermis cells
Provascular tissue cells turn to primary xylem and phloem
older, larger cells turn into metaxylem and metaphloem
parachyma differentiates into root cortex
cells are permeable
little absorption occurs here
External Structure
Organization of Root Systems
single prominant taproot
lateral roots
come out of taproot
radicle
embryonic root
taproot development
Fibrous Root System
adventitous roots
increase absorptive and transport capacities
Taproots
Structure of Individual Roots
roott cap
protects Apical Meristem
micugel
secreted from dictysomes of root cap cells
complex polysaccharide
Zone of elongation
few millimeters long
cells undergo division & expansion
root hair zone
epidermal cells extend out as trichomes
