Chapter 5: Tissues and the Primary Growth of Stems
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Internal organizations of Stems: Arrangement of Primary Tissues
epidermis
outermost surface of an herbaceous stem
chemical
properties
cortex
vascular tissues
interior of the epidermis
two types
pholem
xylem
distributes
conducts
minerals
water
sugar
minerals
vascular bundles
xylem and phloem work together
waterproofing
ingested by
fungi
bacteria
animals
cutin
waxes
Basic Types of Cells and Tissues
sclerenchyma
parenchyma
collenchyma
uneven thick walls
provides plastic support
alive at maturity
lots are dead at maturity
primary walls
elastic support
secondary walls
involved in water transport
fibers
sclereids
long
dead when mature
those alive involved in storage
many dead
isodiametric
Stem Growth and Differentiation
apical meristems
subapical meristems
cells divide by
just below apical meristem
cytokinesis
mitosis
cells are
dividing
growing
External Organization of Stems
leaf axil
nodes
bud scales
internodes
phyllotaxy
auxiliary bud
rhizomes
terminal bud
tubers
important positioning of leaves
decussate
whorled
opposite
spiral
alternate
distichous
leaves per node
leaves two per node
leaves located in four rows
leaves located in two rows only
three or more leaves per node
leaves not aligned with their nearest neighbors
horizontal
only grow for short periods
example
potatoes
allow plants to spread underground
examples
fleshy horizontal stems
bamboo
canna lilies
irises
extreme tip of each stem
young leaves
region between nodes
where leaves are attached
where leaf attaches
stem
protect inside organs
modified scales