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Chapter 5: Tissues and Primary Growth of Stems - Coggle Diagram
Chapter 5: Tissues and Primary Growth of Stems
Stem Growth and Differentiation
subapical meristem
cells grow for region below apical meristem
elongating
constitute first xylem, protoxylem
metaxylem
any type of secondary wall feasible
annular or helical secondary walls
apical meristem
cells grow longer tip
Growth cells allow extension
External Organization of Stems
stem organization
nodes
where leaves are attached
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internodes
region between nodes
leaf axil
on stem above leaf attaches
within is axillary bud
miniature shoot w dormant apical meristem
terminal bud
bud scales
leaves on stem
phyllotaxy
alternate phyllotaxy
one leaf each node
whorled
three+ or more/node
opposite phyllotaxy
two leaves/node
Basic Types of Cells and Tissues
Sclerenchyma
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primary wall and thick secondary wall w lignified
walls elastic
supports plants by strength alone
two types cells:
conducting sclerenchyma
mechanical sclerenchyma
Collenchyma
primary wall thin in some area, thick In some and corners
present in elongating shoot tips
grape vines
young petioles
layer just under epidermis
require glucose
Parenchyma
parenchyma cells have primary walls thin
Chlorenchyma cells
photosynthesis and have chloroplast
Glandular cells
create nectar, fragrance, oils
some choroplast, dictyosomes and endoplasmic reticulum
Transfer cells
short distance transport
increase surface area
parenchyma tissue
most common
all stems share a basic organization also leaves and roots
Internal Organization of Stems
Arrangement of Primary Tissues
Vascular Tissues
vascular systems
water + mineral enter xylem in roots to stem + leaves
not circulatory system
Phloem
distributes sugar and minerals
living
pick up sugar , water transported in
two types conducting cells
sieve cells
associated with albuminous cells
sieve tube members
sieve element
only primary walls
must be alive to conduct
parenchyma cells
nuclei degenerate but cells alive
controlled by companion cells
Cortex
inferior to epidermis
simple, homogenous
contain parenchyma/collenchyma cells
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aerrenchyma
open tissue w large intercellular air spaces
Vascular Bundles
xylem and phloem occur together
located just interior to the cortex
one ring around pith
region parenchyma similar to cortex
all are collateral
primary phloem
primary xylem
Epidermis
outermost surface of herbaceous stem
single layer parenchyma cells
Xylem
conducts water and mineral
two types conducting cells
tracheids
long, narrow
vessel elements
sclerychyma
tracheary element
scarlariform thickening
reticulate thickening
helical thickening
annular thickening
short, wide
