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Root root (Other types of roots and their Mechanisms (prop roots #…
Root
Internal Structure of Root
root apical meristem
cell division occurs throughout the root
more orderly than shoots
quiscent center
reserve healthy cells
mitotically inactive
resistant to radiation and toxic chemicals
it becomes active when the root cap or apical meristem is damaged.
zone of elongation
ground tissue
in the root cortex
older cells
into metaxylem and metaphloem
provascular tissue
develop into primary xylem and primary phloem
it is in the center
cells expand greatly and expand
protoderm
outermost cell
differentiate into epidermis
mature portion of root
root hair
absorption of water and minerals are reduced
endodermis
it is unchanged
continue to mature
passage cells
they are slow to develop
has casparian strips
root cap
cells
undergo cell division
differ as they move towards the side
small and meristematic when it is formed
functions
protects the root
provides the stability of root
zone of maturation
cortex cells enlarge
helps to transport the minerals from the epidermis to vascular tissues
root hairs grow outward
water and minerals absorption
surface area increases
endodermis
water proof cell wall
cylindrical
Casparian Strips
Controls the flow of minerals
External Structure of Root
organization of the root system
seed plants
radicle
gives rise to taproot
small lateral roots
single taproot
fibrous root system
adventitious root
most monocots and some dicots
highly branched
structure of individual root
longitudinal growth
tips pushes to soil
discrete apical meristem
mucigal
rich in carbohydrates and amino acids
rapid growth of microbes around the tip
lubricate the passage of the root
causes the soil to release nutrients ions
root tip
growth in length
Development of Lateral Roots
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new lateral root
invades endodermis
destroys the cells of the epidermis
it is initiated by the divisions in the pericycle
root primordium
it organizes itself into the apical meristem
it causes the endodermis to torn out
pushes outwards
complete lateral root
protoxylem and protophloem differentiate
formed root cap
Other types of roots and their Mechanisms
storage roots
stable environment
long term storage of carbohydrates
Contractile roots
shoots become anchored to the cells
it is important to keep stems at proper depth
contraction caused by change in shape of the cortex
historical root of parasitic flowering plants
very little root like structure remains
Tristerix
grows around the roots to adhere
roots of stranger figs
absorbs nutrients from the rain water
the roots donot contact with the soil for months
it grows rapidly once it touches the soil
prop roots
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buttress root
brace the trunk
upper part grows rapidly
extreme growth through the air
mangrooves
helps in respiration
function
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stabilizers for stem
transports nutrients and minerals to the stem
Arial roots of orchid
spread along the surface of the bark
adapted to the dry environment
Structural connection
Functional connection
Mechanism Connection
