Transcript Document
Why do Venus flytraps have
flytraps?
AP Biology
Plant Nutrition
(Ch 38)
AP Biology
Physiological adaptation
Dogs pee on trees…Why don’t trees pee on dogs?
AP Biology
Physiological adaptation
Dogs pee on trees…Why don’t trees pee on dogs?
NH3
animal waste
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plant nutrient
Nutritional needs
Autotrophic does not
mean autonomous
plants need…
sun as an energy source
inorganic compounds
as raw materials
water (H2O)
CO2
minerals
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Macronutrients
Plants require these nutrients in
relatively large amounts
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C, O, H, N, P, K, Ca, Mg, S
Mineral absorption
Proton pumps
active transport of H+ ions out of cell
chemiosmosis
H+ gradient
creates membrane
potential
difference in charge
drives cation uptake
creates gradient
cotransport of other
solutes against their
gradient
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Micronutrients
Plants require in very small amounts
Cl, Fe, Mn, Bo, Zi, Ni, Mb
primarily cofactors for enzyme function
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Nutrient deficiencies
Lack of essential nutrients
exhibit specific symptoms
dependent on
function of nutrient
dependent on
solubility of nutrient
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Magnesium deficiency
Symptoms
Take 2
fertilizer pellets
& call me in
the morning
chlorosis = yellowing of leaves
Why? What is magnesium’s function?
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Chlorophyll
Why does magnesium
deficiency cause chlorosis?
The chlorosis shows up in older
leaves first, because plant moves
+ to newer leaves. Why?
Mg
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Agronomists
really dig dirt!
The role of soils
Plants are dependent on soil quality
texture / structure
relative amounts of various sizes of soil particles
composition
organic & inorganic chemical components
fertility
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Importance of organic matter
Topsoil
most important to plant growth
rich in organic matter
So don’t rake
your lawn or
bag your leaves
humus
decomposing organic material
breakdown of dead organisms, feces, fallen
leaves & other organic refuse by bacteria &
fungi
improves soil texture
reservoir of minerals
organisms
1 tsp. of topsoil has ~5 billion bacteria
living with fungi, algae, protists, insects,
earthworms, nematodes
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Soil health as a global issue
Not taking care of soil health has
far-reaching, damaging
consequences
1920’s Dust Bowl
lack of soil conservation
growing the same crop
year after year (wheat)
grazing by cattle
bare ground exposed to
wind erosion in winter
drought
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Soil health as a global issue
Soil conservation & sustainable agriculture
maintaining healthy environment
sustainable production of food supply
economically viable farming industry
“A sustainable agriculture does not deplete soils or people.”
– Wendell Berry
contour plowing
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cover crops
crop rotation
Global issues
soil fertility
erosion
irrigation
forestry destruction
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Fertilizers
“Organic” fertilizers
manure, compost, fishmeal
“Chemical” fertilizers
commercially manufactured
N-P-K (ex. 15-10-5)
15% nitrogen
10% phosphorus
5% potassium
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What are the
political, economic,
environmental
issues?
Nitrogen uptake
Nitrates
plants can only take up nitrate (NO3-)
Nitrogen cycle by bacteria
trace path of nitrogen fixation!
root
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What will the plant use N for?
Soybean root nodules
N fixation by Rhizobium bacteria
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symbiotic relationship with bean
family (legumes)
Plow it under?
Why would you
that?
Increasing soil fertility
Cover crops
growing a field of plants just to
plow them under
usually a legume crop
taking care of soil’s health
puts nitrogen back in soil
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erosion control, too
Some plant oddities…
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2006-2007
Parasitic plants
tap into host plant vascular system
Indian pipe
What are the pros and cons?
Mistletoe
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Carnivorous
plants
Sundew
Venus fly trap
Pitcher plant
Why do they do
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this?
In what type of
environment
would they be
found?
Figure 37.15c
Sundews
Pitcher plants
Venus flytrap
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Pitcher plant
Plants of peat bogs
High acid environment
most minerals & nutrients bound up &
are not available to plants
must find alternative sources of nutrients
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Mycorrhizae increase absorption
Symbiotic relationship between fungi & plant
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symbiotic fungi greatly increases surface area for
absorption of water & minerals
increases volume of soil reached by plant
increases transport to host plant
REVIEW
1. How is symbiosis critical to plant
survival and evolution?
2. How do plants take in nutrients?
3. Name two critical nutrients, and state
what outcome their deprivation would
have on plants.
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Any Questions??
AP Biology
2006-2007