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Chapter 6: Tissues and Primary Growth of Stems - Coggle Diagram
Chapter 6: Tissues and Primary Growth of Stems
Basic Types of Cells and Tissues
Parenchyma
most common type of cell
makes up all soft parts of plants
soft leaves
petals
fruits
seeds
thin primary walls
subtypes of parenchyma
chlorenchyma
involved in photosynthesis
have numerous chloroplasts
thin walls allow CO2 and light to enter chloroplasts
glandular cells
secrete
nectar
resins
oils
fragrances
mucilage
high amounts of dictyosomes and ER
transfer cells
mediate short distance transport within cell
increase surface area by having extensive knobs, ridges or other ingrowths
Collenchyma
primary wall is both thin and thick but thicker on corners
exhibits plasticity
reinforces shoot
subterranean roots and shoots do not need collenchyma (supported by soil)
Sclerenchyma
has primary wall and thick secondary wall
highly elastic
two types
conducting sclerenchyma
mechanical sclerenchyma
subdivided into
sclereids (short)
cuboidal shape
brittle
inflexible
fibers (long)
found in areas where strength and flexibility are important
wood (tree trunk)
External Organization of Stems
stems
axis
nodes
where leaves attach
internodes
regions between nodes
leaf axil
area right above where leaf attaches
phyllotaxy
arrangment of leaves on stem
shoots (stems + buds, flowers, leaves, etc)
buds
axillary bud
covered by bud scales
small, corky, waxy
terminal bud
stolons (runners)
internodes especially long and thin
leaves do not expand
bulbs
short shoots with thick fleshy leaves
onions, garlic, daphodils
corms
vertical thick stems
thin papery leaves
rhizomes
fleshy horizontal stems
bamboo
irises
canna lilies
tubers
horizontal stems
nutrient storage
potatoes
Internal Organization of Stems: Arrangment of Primary Tissues
Epidermis
single layer of living parenchymal cells
cutin
fatty substance
makes wall impermeable to water
makes up cuticle layer
resists digestive enzymes
provide defense against fungus/bacteria
guard cells
stomatal pore
constitute stomata
trichomes/hairs
die shortly after maturity
Cortex
interior to epidermis
simple and homogeneous
composed of photosynthetic parenchyma
Vascular Tissues
distributes sugars, minerals, oxygen and CO2
xylem
conducts water and minerals
tracheids
vessel elements
entire stack of elements is a vessel
tracheary elements
circular bordered pits
border (thick wall)
annular thickenings
helical thickening
scalaform thickening
reticulate thickening
perforation
phloem
distributes sugars and minerals
sieve cells
sieve tube members
sieve element
sieve pores
sieve area
sieve tube
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Stem Growth and Differentiation
apical meristems
new cells at tips of stem
primary tissue
tissues produced by apical meristems
primary growth
subapical meristem
region just below apical meristem
protoxylem
first xylem to appear
metaxylem
largest treachery elements of all
protophloem
metaphloem
cells closest to metaxylem
small size
protoderm
epidermal cells in early stages of differentiation
provascular tissues
young cells of xylem and meristem
ground meristem
equivalent stages of pith and cortex
