5. Vascular tissues Download

Transcript
PHARMACOBOTANY
LECTURE 5.
PLANT TISSUES III.
VASCULAR TISSUES
VASCULAR TISSUES
Xylem
• transporting water and
mineral substances
• from the root upwards to
other plant organs
Phloem
• carries photosynthetic
assimilates
• from the leaf (=place of
photosynthesis) downwards
to other plant organs
Vascular tissues
XYLEM
PHLOEM
Procambium
primary xylem
primary phloem
protoxylem
protophloem
metaxylem
metaphloem
tracheids
tracheas
Cellular elements:
sieve cells
sieve tubes
xylem parenchyma cells
xylem fibers
companion cells
phloem parenchyma cells
phloem fibers
Cellular elements of vascular tissues
sieve tube element
with companion cell
PHLOEM
cambiform
cell
phloem
parenchyma
phloem fiber
c
xylem
a
parenm tracheid
chyma
b
i
u
m
trachea element
XYLEM
xylem fiber
XYLEM – CELLULAR ELEMENTS
Tracheids / Water-conducting cells:
elongated cells, pointed end walls,
lignified cell walls  dead cells
Tracheas / Vessels: trachea elements / vessel members
dead cells, end walls are perforated or disappear
Xylem parenchyma cells: living, cytoplasm-containing cells,
storage (transport)
Xylem fibers: elongated, lignified cell walls, dead cells
supporting function
XYLEM
sclerenchyma
fibers
tracheids: primary cell
wall with pores
end wall
primary cell wall
with pores
total perforation
tracheids
xylem
elements
Tracheas
root of liquorice (Glycyrrhiza glabra)
xylem fibers
CELL WALL THICKENING
I. CENTRIFUGAL
- new cell wall material is deposited on outer surface of primary
cell wall
- cells not embedded in tissues (e.g. pollen, spores, trichomes)
II. CENTRIPETAL
- cell wall thickening inwards, towards cell lumen
(1) Evenly
• only certain walls (epidermis, endodermis)
• each cell wall (sclereids, sclerenchyma fibers)
(2) Unevenly
• Affects smaller part of cell wall:
annular, spiral, reticulate, scalariform
• Affects larger part of cell wall:
pits, bordered pits, channels in cell wall
Centrifugal cell wall thickening
pollen grains and spores
Centripetal cell wall thickening
b: annular
c: spiral
d: reticulate
e: pitted
f: channeled
1-3.:
bordered
pits
spiral
bordered pits
annular
pitted cell wall
bordered pits
PHLOEM – CELLULAR ELEMENTS
Sieve cells: elongated, cylindrical, protoplasm containing living
cells, with oblique, pitted or reticulate end walls
• side walls: sieve areas with pores (cell-to-cell communication)
- cytoplasm strands to adjacent cells
Sieve tubes: sieve tube elements, end walls: perforated
sieve plate
Companion cells: accompany sieve tube elements in
angiosperms; living cells containing cytoplasm and nucleus
Phloem parenchyma cells: living, cytoplasm-containing,
storing nutrients
Phloem fibers: elongated, sharply tapering ends, cellulose
walls, strengthen the vascular tissue
sclerenchyma
cells
PHLOEM
sieve plate
sieve element
companion cell
e: epidermis
ek: primary cortex
hr: phloem fiber
h: phloem
k: cambium
phloem fibers of hemp
Vascular tissues
Cambial ring / Vascular cambium
secondary xylem
secondary phloem
a) cellular elements – like in primary
xylem
phloem
b) transitory elements:
cambiform cells
fiber tracheids
divided phloem fibers
divided xylem fibers
supplementary fibers
supplementary fibers
Types of vascular tissue arrangement
Procambium
contiguous
annular vascular tissue
fascicular
vascular bundles
VASCULAR BUNDLE TYPES
Simple
Radial
Collateral
closed
open
Compound
Concentric
bicollateral
amphicribral
amphivasal
phloem
xylem
cambium
monocot stem
dicot root
simple
vasc.bundles
dicot stem
phloem
xylem
phloem
monocot
root
xylem
1 closed collateral
2 open collateral
3 bicollateral
4 amphivasal
5 amphicribral
phloem
xylem
compound
bundles
Vascular bundles in circle – dicot plants
stem of Ambrosia artemisiifolia
stem of Aquilegia sp.
Scattered vascular bundles
– monocot plants
stem of maize (Zea mays)
rhizome of Iris sp.
phloem
xylem
closed collateral bundle
(Lilium)
open collateral bundle
(Aristolochia)
vascular
cambium
Structure of open collateral bundle
xylem:
tracheid
trachea
sieve tube
phloem
companion cell
parenchyma
Collateral open bundles
petiole of Tussilago farfara
stem of Aquilegia sp.
Collateral closed bundles
leaf of eucalyptus
Collateral closed bundles
stem of maize
xylem
phloem
cambium
phloem
Cucumis: bicollateral vascular bundle
Polypodium rhizome cross section
xylem
phloem
amphicribral vascular bundle
Acorus calamus
rhizome cross section
amphivasal
vascular bundle
xylem
phloem
Bundle sheats
flower of Tilia sp.
leaf of oleander
Thickening types of the stem
Helianthus type
Aristolochia type
Ricinus type
Tilia type
stem of St. John’s wort
Structure of woody stems
rhytidoma
Pinus
fiatal
ág4x
phloem
xylem
resin
duct
cambium
epithel cells
young stem of Pinus griffithii
cells of ground tissue
rhizome of Tussilago farfara
Root
Triticum root cross section
xylem
bundle
polyarch root
Ranunculus root cross section
xylem
bundle
phloem
bundle
tetrarch root
aerial root of philodendron (Monstera deliciosa)
xylem
phloem
Similar