Roots Flashcards
Where does the root originate?
Embryonic root or Radicle
Give at least 3 functions of Roots
Absorption of water and dissolved
minerals
Anchorage
Food storage
Transport of materials to and from the
shoot
specialized functions: photosynthesis &
vegetative reproduction, etc.
A root with a well-developed Primary root.
Taproot
Also called Branch roots
Lateral roots
Taproot is mostly found where?
Dicots
give the main function of a taproot
To maximize support and storage
numerous
long & slender lateral
roots of about the
same size & no
dominant primary
root
Fibrous roots
Fibrous roots are mostly found where?
Monocots
Main function of fibrous roots
Maximize absorption
roots that
form on organs other
than roots (or other than
the radicle)
Adventitious
where are adventitious mostly commonly occur?
rhizomes of
ferns, club mosses &
horsetails; in corn
(support)
Main function of an adventitious roots
primary means of
vegetative reproduction
This covers the root tip and senses environmental stimuli
Root cap
what does root cap produces?
Mucigel
composed of inactive cells
- organizes patterns of primary growth & replaces damaged cells
of the adjacent meristem
Quiescent center
give 3 zones of subapical region
Zone of Cellular Division/Meristematic
Region
* Zone of cellular elongation
* Zone of cellular maturation/
differentiation
Zone of actively dividing cell
Zone of Cellular
Division/Meristematic
Region
How often does the apical meristem cell divides per day?
once or twice
transitional meristems arise from the tips of ___ and ___
roots and shoots
forms the epidermis
Protoderm
forms the ground tissue
Ground meristem
forms the primary phloem and xylem
Procambium
larger, elongated cells w/
less defined nucleus but w/
prominent vacuole
Zone of cellular elongation
central
conductive core
Stele
takes place
where vascular elements
begin to form a Stele
Zone of cellular
maturation/
differentiation
____develop as
protuberances from
epidermal cells
Root
____exists on root but
not on root hairs
Cuticle
lateral
Extensions of root
Absorb water and
nutrients from soil
Root Hairs
Diverts water & dissolved minerals into the cytoplasm of endodermal cells
Casparian strip
cells packed tightly; lined with lignin & suberin
Endodermis
3 layers of Cortex
Hypodermis
Storage parenchyma cells
Endodermis
outermost layer of cells forming the initial covering on a root
Epidermis
ground tissue that surrounds the vascular cylinder or stele
Cortex
produces
branched roots (secondary or
lateral roots)
Pericycle
Pith of dicots are filled with?
Solid core of Xylem
Pith of monocots are filled with
Parenchymatous Pith
Monocot roots exhibit what type of stele?
Siphonostele
Dicot roots exhibit what type of stele?
Protostele
Number of protoxylem in Monocots?
More than 10 ( Polyarch)
Number of protoxylem in dicots?
2- 5 ( Di, tri, tetra, pentarchs)
Where does lateral roots arise from?
Pericycle
adventitious roots found above the
ground (eg. Corn, poison ivy)
Prop roots
enlarged primary or
secondary roots that stores food
Food storage roots
absorb moisture from the
atmosphere & also undergo photosynthesis
(eg. Black mangrove, vanilla orchid,
Philodendron)
Aerial Roots
large or plantlike roots at the
base of some tropical trees; help stabilize &
support trees
Buttress Roots
involved in asexual
reproduction
Vegetative roots
roots w/
localized swellings in
response to infection by
nitrogen fixing bacterium
Noduled roots
nitrogen fixing bacterium
Rhizobium
fungus roots”
Mycorrhizae
provides protection against pathogens and increase surface area for the absorption of essential nutrients
fungus
provides food for the fungus in the form of sugar and amino acids
Plants
where a symbiotic relationship forms between a plant and a fungus.
Fungus roots
for movement by
pulling a plant into the more stable
environment of deeper soil
Contractile roots
attraction of water to cellulose microfibrils
causing them to move apart & the cell walls to swell
Imbibition
How does material pass through roots?
root hairs cortex endodermis pericycle xylem
Storage of food occurs in__
in cortex (chiefly)
in parenchyma of stele (lesser extent)
Growth occurs in ___
length - tips of roots
diameter- cambium bet xylem & phloem
How does root conducts absorption
Osmosis
Imbibition
Diffusion of solutes
active absorption
