Download I. Plants

Biology 102 Environmental Biology
Plants/Agriculture Unit
Page 1 of 15
Based on Mader, Sylvia S. 1996. Biology - 5th Ed. WCB
and
Cox, G.W. 1997. Conservation Biology - 2nd ed. WCB
and
Levine, J.S. and K.R. Miller. 1994. Biology: Discovering Life. D.C. Heath
and
Lewis, Gaffin, Hoefnagels & Parker. 2004. Life - 5th ed. McGraw Hill
[Chapters 26 & 27]
Plants
Reading: Chapters 26 & 27 in Lewis et al.
I.
Plants
A.
Basic Needs
1.
Sunlight
a)
Trees grow to it
b)
Algae may swim to it
c)
Need for support
2.
Water
a)
Need for roots
3.
Reproduction
a)
Special structures
b)
Plants can’t move
(1)
B.
Evolution – movement onto land
1.
Must solve 3 problems
a)
Support
b)
Water to leaves
(1)
2.
D:\769853838.doc
Replacement of water as a means for mixing gametes
A lot of work to raise gallons of water to the top of a tall tree
c)
Replacing water as a medium for sperm to swim in
Solutions
a)
Roots
b)
Vascular tissue
c)
Pollen
May 4, 2017
Biology 102 Environmental Biology
Plants/Agriculture Unit
Page 2 of 15
Figure 26.1A p 515
C.
Parts of a plant:
1.
Three main parts:
a)
Roots – obtain water, nutrients, anchor plant
b)
Stems – hold up plant, transfer water, nutrients, sap
c)
Leaves – photosynthetic center
Figure 26.12 p. 525
2.
D:\769853838.doc
3 tissues
a)
dermal tissue - protection
b)
vascular tissue – moving materials
c)
ground tissue – support, photosynthesis
May 4, 2017
Biology 102 Environmental Biology
Plants/Agriculture Unit
Page 3 of 15
Figure 26.1b p. 515
3.
Meristems
a)
Apical meristem
(1)
(2)
b)
lateral meristem
(1)
(2)
c)
D:\769853838.doc
at the tips of roots
increase in length
circles stems and roots
increase in girth
differentiation – transformation of one of the divided
meristem cells into a specialized cell
May 4, 2017
Biology 102 Environmental Biology
Page 4 of 15
Plants/Agriculture Unit
Figure 26.2 page 516
4.
Cell types:
a)
Epidermal cells
(1)
Covered with extracellular cuticle
(2)
Guard cells
Figure 26.5 p. 519
Ground Tissues
D:\769853838.doc
May 4, 2017
Biology 102 Environmental Biology
b)
Parenchyma cells – ground tissue
(1)
c)
Support of growth areas
Sclerenchyma cells - ground tissue
(1)
(2)
(3)
Vascular tissues
e)
Storage, photosynthesis
Collenchyma cells - ground tissue
(1)
d)
Page 5 of 15
Plants/Agriculture Unit
Support of non-growth areas
Dead when functional
Hard structures, fibers
Xylem – transports water, minerals up
(1)
(2)
(3)
Comprised of tracheids or vessel elements
Transport water
Dead when functional
Figure 26.6 p. 520
f)
Phloem – transports sap – both ways
(1)
(2)
Sieve-tube members – no nucleus
Companion cells
Figure 26.7 p. 520
D:\769853838.doc
May 4, 2017
Biology 102 Environmental Biology
5.
Plants/Agriculture Unit
Page 6 of 15
Roots
a)
Primary roots
b)
Secondary roots
Figure 26.14 p. 526
Figure 26.15A & B p. 527
D:\769853838.doc
May 4, 2017
Biology 102 Environmental Biology
Plants/Agriculture Unit
Page 7 of 15
Figure 26.15 C, D & E p. 527
c)
epidermis
(1)
d)
e)
(1)
Figure 26.16 p 528
D:\769853838.doc
Root hairs
Cortex
Endodermis
Casparian strip
Figure 26.17 p. 528
May 4, 2017
Biology 102 Environmental Biology
II.
Plants/Agriculture Unit
Page 8 of 15
Transport
Figure 27.1 p. 537
A.
Water movement
1.
3 forces:
a)
root pressure
b)
capillary action
c)
transpiration
(1)
2.
3.
Ultimately powered by the sun
100 liters/day = 4 liters/hr = 4 kg/hr = 10 pounds / hr up 300
feet.
Figure 27.6 p. 543
D:\769853838.doc
transpiration is made effective by:
(a)
tension - “pull” from leaves
(b)
cohesion – water molecules stick together
(c)
adhesion – water sticks to walls of xylem
Figure 27.7 p. 543
May 4, 2017
Biology 102 Environmental Biology
B.
Plants/Agriculture Unit
Page 9 of 15
Water uptake by roots
1.
Active transport of mineral ions into roots
2.
Water follows due to osmotic pressure
3.
Endodermis and Casparian strip regulate water flow – water
must move through cells
4.
High salt levels in soil can pull water out of the root hairs
a)
Halophytes tolerate higher salt concentrations
Figure 27.8 p. 544
C.
Sap movement
1.
Pressure/flow hypothesis
a)
Sugars produced in leaves
b)
Sugars pumped into phloem
c)
Water follows by osmosis
d)
Roots remove sugar, cause gradient which draws sugar and
water to roots
e)
Water usually moves in the opposite direction of sap
Figure 27.9 p. 545
D:\769853838.doc
Figure 27.1 p. 546
May 4, 2017
Biology 102 Environmental Biology
D.
D:\769853838.doc
Plants/Agriculture Unit
Page 10 of 15
Tree stems
1.
Two layers of meristem tissue
a)
Vascular cambium produces new xylem to inside, phloem to
outside
b)
Cork cambium forms new cork (bark) to outside
2.
Annual rings – xylem produced more rapidly in spring
May 4, 2017
Biology 102 Environmental Biology
Plants/Agriculture Unit
Page 11 of 15
Figure 26.19 p. 530
Figure 26.19 p. 530
Figure 26.20A p. 530
Figure 26.20B p. 530
Figure 26.21 p. 532
D:\769853838.doc
May 4, 2017
Biology 102 Environmental Biology
Figure 26.21 p. 532
III.
Page 12 of 15
Plants/Agriculture Unit
Figure 26.21 p. 532
Plant Growth
A.
Seeds
1.
Three parts
a)
Embryo
b)
Stored food
c)
Seed coat
2.
Monocots:
a)
One cotyledon
b)
Food stored in endosperm
c)
Grasses (corn, rice, wheat, etc)
3.
Dicots:
a)
Two cotyledons
b)
Food stored in cotyledons
c)
Woody plants
Figure 28.10 p 561
D:\769853838.doc
Figure 28.13A p565
May 4, 2017
Biology 102 Environmental Biology
Plants/Agriculture Unit
Page 13 of 15
Figure 28.13B p565
B.
Dormancy
1.
Period of inactivity by the seed
2.
Allows bad growing seasons to be bypassed
3.
May last days to 12,000 years
4.
Many seeds need drought, damage to seed coat, or freezing
temperatures before germination
Plant nutrients – Figure 27.2 p. 538
IV.
A.
1.
Materials needed for photosynthesis
Water - source of hydrogen
a)
taken in through roots
b)
aided by mycorrhizae
c)
transported up trunk via xylem
d)
lost through stomata - transpiration
e)
Stomata open due to turgor pressure
f)
Turgor pressure requires water
g)
No water - stomata close, reduces water loss
D:\769853838.doc
May 4, 2017
Biology 102 Environmental Biology
2.
a)
b)
c)
CO2 - source of carbon
Taken in at stomata
Stomata open only when water available
Taken in at night by desert plants
a)
b)
c)
d)
e)
Nitrogen - needed for amino acids
Taken in as NO3- dissolved in H2O
Nitrogen fixed by bacteria in soil
Nitrogen present in animal wastes, fertilizers
Rhizobium in nodules of legumes also fix N2
In short supply for bog plants --> carnivory
3.
4.
Phosphorous - used in ATP, DNA, cell membranes
a)
Taken in with water as PO4
b)
uptake enhanced by mycorrhizae
c)
"mined" from decaying organisms
5.
a)
B.
Page 14 of 15
Plants/Agriculture Unit
Magnesium - used in chlorophyll
taken up with water
Sources of minerals
1.
Fertilizers
a) N-P-K ratios --> nitrogen - phosphorous - potassium
b) Elements removed from soil most quickly
c) = 5% nitrogen, 10% phosphorous, 5% potassium
d) Test soil to determine proper ratio
2.
Mineral availability - affected by soil
Property of pH - acids leach minerals from soils
Under acid conditions soil releases aluminum and iron rather than
calcium, magnesium and potassium
c) Aluminum and iron may be toxic to the plant
d) Plants can use energy to concentrate minerals far above levels
found in the soil
a)
b)
3.
a)
b)
c)
Epiphytes - getting by without soil
Some have roots, get water from atmosphere or rain
Bromeliads
Some send haustoria into plant for water or sugars or both
D:\769853838.doc
May 4, 2017
Biology 102 Environmental Biology
C.
1.
2.
3.
Plants/Agriculture Unit
Page 15 of 15
Agriculture
Human recreation of natural systems
Only cycles if wastes returned to soil
Otherwise --> mining soil
1.
a)
Practices:
preparing soil
(1)
(2)
(3)
(4)
(5)
b)
slash-and-burn
machinery
soil erosion
use of fossil fuels
soil compaction
monoculture
(1)
(2)
c)
efficiency
susceptibility to disease, pests
fertilizers
(1)
(2)
(3)
d)
replace lost nutrients
expense
eutrophication
pesticides
(1)
D:\769853838.doc
attempt to deal with pest problems caused by monoculture
May 4, 2017