Plant Anatomy Spikelet Inflorescence Internode Culm (stem) Node (joint) Rhizome Stolon Leaf.
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Plant Anatomy
Spikelet
Inflorescence
Internode
Culm (stem)
Node (joint)
Rhizome
StolonLeaf
Plant TISSUES•Dermal
–epidermis (“skin” of plant)–single layer of tightly packed
cells that covers & protects plant
•Ground–bulk of plant tissue –photosynthetic mesophyll,
storage •Vascular
–transport system in shoots & roots
–xylem & phloem
Plant CELL types in plant tissues•Parenchyma
–“typical” plant cells = least specialized–photosynthetic cells, storage cells–tissue of leaves, stem, fruit, storage roots
•Collenchyma–unevenly thickened primary walls–support
•Sclerenchyma –very thick, “woody” secondary walls–support–rigid cells that can’t elongate–dead at functional maturity
If I’d onlyhad triplets!
Parenchyma Parenchyma cells are unspecialized, thin, flexible & carry out many metabolic
functions all other cell types in plants develop from parenchyma
Fig. 38.12a
Collenchyma Collenchyma cells have thicker primary walls & provide support
help support without restraining growth remain alive in maturity
the strings in celery stalksare collenchyma
Fig. 38.12b
Collenchyma
Celery
Sclerenchyma•Thick, rigid cell wall
–lignin (wood)–cannot elongate–mostly dead at maturity
•Cells for support–xylem vessels–xylem tracheids–fibers
•rope fibers–sclereids
•nutshells•seed coats •grittiness in pears
Fig. 38.12c
Schlerenchyma
hau – used to make rope
tracheids
vessel elements Vascular tissue
Aaaah…Structure–Functionagain!
vessel element
dead cells
Xylem move water & minerals up from roots dead cells at functional maturity
only cell walls remain need empty pipes to efficiently move H2O transpirational pull
Fig. 4.9
Fig. 38.13b
Fig. 38.13a
Fig. 4.6
Phloem: food-conducting cells carry sugars & nutrients throughout plant
sieve tube
companion cell
living cells
plasmodesmata sieve plate
Phloem: food-conducting cells sieve tube elements & companion cells
Fig. 38.14a
Fig. 38.14b
Phloem•Living cells at functional maturity
–cell membrane, cytoplasm•control of diffusion
–lose their nucleus, ribosomes & vacuole•more room for specialized transport of
liquid food (sucrose)
•Cells –sieve tubes
•sieve plates — end walls — have pores to facilitate flow of fluid between cells
–companion cells•nucleated cells connected to the sieve-tube •help sieve tubes
Aaaah…Structure–Functionagain!
Fig. 38.15
Cross section of root•Vascular bundle (Stele) = contains xylem and phloem•Cortex•Epidermis•Root hairs
–Absorb water and minerals
Vascular tissue in roots: dicot
xylemphloem
Cross-section of a root
xylem
phloem
Vascular tissue in roots: monocot
Root Cross Section
Vascular tissue in stems
dicottrees & shrubs
monocotgrasses & lilies
collect annual rings
Cross-section: young dicot stem with ring of vascular bundles
Fig. 38.25a
Fig. 38.25b
Monocot stem section showing scattered vascular bundles and enlargement of single vascular bundle (“monkey face”).
Woody dicots
•Discrete vascular bundles replaced by continuous rings of xylem
•Each ring is xylem produced during one growing season
•Vascular cambium
Fig. 38.7a
Fig. 38.7b
Cross-section: woody stem showing 3 years of secondary growth. Note pith at center. Dark (reddish) ring is the bark containing a layer of living phloem and outer dead cork.
Stems: Secondary growth•Vascular tissue, (xylem) makes up the bulk of the stem•Form tree rings
Lilac leaf cross section
Fig. 38.34
Fig. 38.8
Fig. 38.33
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