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Function shapes
structure…
Structure enables
function
What functions and
structures exist?
Those passed on by
past generations…
Evolution
CB 35.2
Plants grow and
reproduce, as well
as, respond to the
environment.
Plants grow and reproduce, respond to the
environment… today- transport
CB 35.9
Types of Plant
Cells:
defined by
function and
cell wall
CB 6.9
Parenchyma cells- most common cells;
primary cell walls
CB 35.9
60 m
Parenchyma in a
stem
CB 35.16
Collenchyma cells- unevenly thickened cell
walls; flexible support
CB
35.9
80 m
Collenchyma in a leaf
Sclerenchyma cells- Thickened secondary
walls (inside primary wall); with lignin; rigid
5 m
25 m
CB 35.9
Water conducting
cells of Xylem:
vessels
and
tracheids
(types of sclerenchyma)
CB 35.9
100 m
Sugar conducting cells of
Phloem: sieve-tubes and
companion cells
CB 35.9
30 m
15 m
CB 35.18
Plants transport
water, sugar,
minerals, hormones,
etc through the
vascular system
comprised of xylem
and phloem
CB 36.2
Water travels
from ground out
through stomata
via xylem
CB 36.2
The exit of water
through stomata
is accompanied
by gas exchange
CB 36.2
Sunlight powers
photosynthesis
and these sugars
are transported
via phloem
The direction of
Phloem transport is
versatile.
Plant cell to cell transport can occur by two
pathways: symp[lastic and apoplastic
CB 36.8
plasmodesmata
Sugar is loaded at sources and unloaded at sinks
CB 36.17
CB 36.18
Sugar is loaded
at sources and
unloaded at
sinks
source:
leaf
sink:
root,
flower,
emerging
leaf etc…
CB 35.18
Plants transport
water, sugar,
minerals,
hormones…
CB 36.7
Much of plant support
comes from turgor pressure.
CB 36.13
Water moves from
the ground through
roots into the shoot
and out stomata in
the leaves.
CB 35.12 and .13
In roots the
vascular bundle
is in the center
CB 36.9
The casparian strip of
the endodermis keeps
water from entering
the xylem via a
purely apoplastic
route.
CB 36.13
What moves the
water through the
xylem?
CB 35.17
Stomata
control entry
of CO2 and exit
of H2O from
plant leaves
CB 36.12
Stomata
Stomata on the underside of a leaf
CB 36.15
Guard cell
opening is
regulated by
turgor
CB 36.13
What moves the
water through the
xylem?
Transpiration,
Adhesion,
Cohesion, and
Tension
water transport
limits plant growth
More xylem is needed for more water
transport: secondary growth
phloem
xylem
Xylem is tough, and full of lignin- inhibits
the ability to use plants to produce biofuels
phloem
xylem