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Structure and Development of Roots - Coggle Diagram
Structure and Development of Roots
Root Systems
Dicots
Primary root
Taproot
Monocots
Primary root
Adventitious roots
Root Functions
Primary Functions
Other Functions
Growth
Region of Maturation
Region of Elongation
Region of Cell Division
Provides structural support
Anatomy
Xylem
Cell(s)
Parenchyma cells
Meristem
Apical Meristem
Initials
Cells that maintain the meristem as a
continuing source of new cells
Dervatives
New body cells derived from initials.
Sieve cells
Sieve -tube elements
The only type of food-conducting cell in
angiosperms.
arranged end-on-end in longitudinal series called sieve tubes
Sieve-plates: the part of the wall bearing the sieve areas with larger pores.
Sieve plates present in sieve-tube elements but absent in sieve cells.
Unlike trachery elements, sieve elements have living protoplasts at maturity
Albuminous cells
(specialized)
Containing all of the components of a plant living
cell
Believed to play a role in delivery of substances to the sieve
elements
Die when their associated sieve elements die
Companion cells
(specialized)
Containing all of the components of a plant living cell
Associated and closely developmentally with sieve-tube
elements (same mother cell)
Believed to play a role in delivery of substances to the
sieve-tube elements
• Acts as a life-support system for the sieve-tube element
Epidermis cells
Subsidiary cells
Guard cells
Guard cells are associated with epidermal cells called subsidiary cells, that differ in shape from other epidermal cells
Guard cells regulate the small pores, or stomata
Control the movement of gases, including water
vapor, into and out of stomata.
The term “stoma” commonly is applied to the
pore and the two guard cells.
Although stomata occur on all aerial parts,
they are most abundant on leaves.
Tissue
ground tissue
Sclerenchyma tissue
Form continuous masses— sclerenchyma tissue
Small groups, individually, or among other cells.
Develop in any or all parts of the primary and
secondary plant bodies
Often lack protoplasts at maturity.
Sclerenchyma cells: thick, often lignified,
secondary walls.
Fibre (type 1)
Generally long, slender cells
Vary in length
Hemp, jute and flax
Sclereids (Type 2)
Short and often branched
Seed coats and nuts
Collenchyma tissue
Alive at maturity
Typically elongated
Unevenly thickened walls
Non-lignified primary walls
Support of young, growing organs
Occur in discrete strands or as continuous cylinders
beneath the epidermis in stems and petioles (leaf stalks).
Vascular tissue
Xylem Tissue
Transport of water and minerals, in
support, and in food storage.
In the primary plant body, the xylem
is derived from the procambium.
During secondary growth, the xylem is derived from the vascular cambium.
Together with the ploem, the xylem forms a continuous system of vascular tissue extending throughout the plant body.
Tracheary elements
(principle conductiong cells)
Two types
-> Tracheids and vessel elements
Elongated cells with secondary wall thickenings
and lacking protoplasts at maturity
Pits in their walls
Vessels are unlike tracheids and contain perforation -> areas lacking primary and secondary walls -> More efficient conductors of water than tracheids
Phloem
The phloem may be primary or
secondary in origin
Protophloem
Metaphloem
Differentiates later and, in plants without secondary growth, constitutes the only conducting phloem in adult plants
Dermal tissue
Trichomes
Absorption of water and minerals from
the soil (Root hairs )
Reflect solar radiation, lower leaf
temperatures, and water loss
Saltbush (Atriplex) secretes salty
solutions from the leaf tissue
Provide a defense against insects.
The trichomes of carnivorous plants play an important role in trapping insect prey
Periderm
Balance Between Shoot and Root system
Symbiotic Nitrogen Fixation
Growth in Root Length
Rootcap and Mucilage
Root Movement and Response
Root Apical Organisation
Primary Root Structure
Function of Endodermis and Exodermis
Morphogenesis
Differentation