Download Plants Group 2 PPT

Modified stems
Runner or stolin
◦ Aspen, strawberries, grass
◦ Grow on surface
◦ For asexual reproduction
 Rhizome
◦ Iris, ginger, potato, onion
◦ Grow underground
◦ Store food & DNA for new plant
◦ Tuber: end of rhizome
 Bulb – underground shoot
◦ Onion
◦ storage leaves

C. Leaves
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◦
◦
◦
epidermis of underside interrupted by stomata (pores)
Mesophyll: ground tissue between upper/lower epidermis
Parenchyma: sites of photosynthesis
Cuticle: waxy layer
Three Tissue
Systems
A. Dermal Tissue
Single layer, closely packed cells that cover
entire plant
 Protect against water loss & invasion by
pathogens
 Cuticle: waxy layer
 Epidermis, periderm

B. Vascular Tissue
Continuous throughout plant
 Transports materials between roots &
shoots

stele
1. Xylem: transport H2O and minerals up from
root
2. Phloem: transports food from leaves to
other parts of plant
C. Ground Tissue
Anything that isn’t dermal or vascular
 Function: storage, photosynthesis, support
 Pith: inside vascular tissue
 Cortex: outside vascular tissue

III. Cell Types
Parenchyma: most abundant
 Perform metabolism, synthesizes & stores
organic products
B. Collenchyma: grouped in cylinders, support
growing parts of plant
C. Sclerenchyma: rigid support cell
D. Xylem: water conduction
 Tracheids, vessel elements – dead, tubular,
elongated cells
E. Phloem: sugar, organic cmpd. conduction
 Sieve tubes, plates, companion cells – alive cells
which aid movement of sugar
A.
WATER-CONDUCTING CELLS OF THE XYLEM
PARENCHYMA CELLS
Vessel
Parenchyma cells in Elodea
leaf, with chloroplasts (LM)
Tracheids
100 µm
60 µm
Pits
COLLENCHYMA CELLS
80 µm
Cortical parenchyma cells
Tracheids and vessels
(colorized SEM)
Vessel
element
Vessel elements with
perforated end walls
Tracheids
SUGAR-CONDUCTING CELLS OF THE PHLOEM
Collenchyma cells (in cortex of Sambucus,
elderberry; cell walls stained red) (LM)
Sieve-tube members:
longitudinal view
(LM)
SCLERENCHYMA CELLS
5 µm
Companion
cell
Sclereid cells in pear (LM)
Sieve-tube
member
Plasmodesma
25 µm
Sieve
plate
Cell wall
Nucleus
Cytoplasm
Companion
cell
30 µm
15 µm
Fiber cells (transverse section from ash tree) (LM)
Sieve-tube members:
longitudinal view
Sieve plate with pores (LM)
Primary and Secondary Growth
(apical vs. lateral meristems)
Concept 35.3 Primary growth lengthens roots and
shoots
Root Hairs
Zone of Maturation: growth & differentiation complete;
fully mature cells
Zone of Elongation: cells elongate; push root tip ahead
Zone of Cell Division: apical meristem; new cells produced
Root cap: protects meristem as it pushes through soil; also
secretes polysaccharide lubricant