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Ch:6 Tissues and Primary Growth Stems - Coggle Diagram
Ch:6 Tissues and Primary Growth Stems
Three parts: Leaves, Stem and Roots
Basic Types of Cells and Tissues
Parenchyma
Only has thin primary walls.
most common, found in soft parts of plants.
sub types
Transfer cells: mediate short distance transport
Glandular Cells: secrete nectar, fragrances and mucilages etc.
Chlorenchyma: involved in photosynthesis
Collenchyma
primary walls remain thin but becomes thick in some areas
wall exhibits plasticity
Present in elongating shoot tips
Sclerenchyma
third layer
has both primary and secondary wall.
Two types
Conducting Sclerenchyma
Mechanical Sclerencyma
External Organization of Stems
nodes: leaves are attached
internodes: region between two nodes
axillary bud: miniature shoot with dormant apical meristem
terminal bud: extreme tip of each stem.
Phyllotaxy: arrangement of leaves
Internal Organization of Stems
Epidermis
Outermost surface with single parenchyma cells.
absorbs and expels substances
shields delicate internal parts
Cortex
interior to epidermis
has photosynthetic parenchyma and chollenchyma
has cortical chamber for buoyancy
Vascular Tissues
Xylem
Trachids
long and narrow
tubular wall
Vessel Elements
conducts water and minerals
Phloem
two types of conducting cells
Sieve cells
long, narrow
small and located over cell surface
sieve tube members
side, short
companion cells
Vascular bundles
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Xylem and phloem together
angiosperms has one ring pith
monocots has scattered vascular bundles
collateral
Stem Growth and Differentiation
apical meristem
cells divide by mitosis
sub-apical meristem
region below appeal meristem
divide to form new cells
protoxylem : first xylem
metaxylem: largest treachery element
protophloem: matured exterior cells
metaphloem: cells closest to metaphlowm
