Physiological adaptation Dogs pee on treesWhy dont trees pee on dogs NH 3 animal waste plant nutrient Nutritional needs Autotrophic does not mean autonomous plants need sun as an energy source ID: 785131
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Slide1
Plant Nutrition
(Ch. 37)
Slide2Physiological adaptation
Dogs pee on trees…Why don’t trees pee on dogs?
NH
3
animal waste
plant nutrient
Slide3Nutritional needs
Autotrophic does not
mean
autonomous
plants need…
sun
as an energy sourceinorganic compounds as raw materialswater (H2
O)CO2minerals
Slide4Macronutrients
Plants require these nutrients in relatively large amountsC, O, H, N, P, K, Ca, Mg, S
Slide5For what & from where?
C
macromolecule synthesis
CO
2
O
macromolecule synthesis
CO
2
H
macromolecule synthesis & proton pumps
H
2
O
N
protein & nucleic acid synthesis
soil
P
nucleic acids, ATP, phospholipids
soilKstomate control, water balancesoilCacell wall & membrane structure, regulationsoilMgchlorophyllsoilSproteins, enzymessoil
to make all plant proteins
establish a strong root system in young plants, growth
Flowers, absorption of water, strong roots, root crops (ie. carrots)
Cell walls, nutrient and soil conditioner
Local Long Island soil issues
Granite
Acid soils bind up
mineral ions
pH by adding lime
Quartz
silica based soils
- low in P
- can be acid
Slide7Micronutrients
Plants require in very small amountsCl, Fe, Mn, Bo, Zi, Ni, Mb
primarily cofactors for enzyme function
Slide8Nutrient deficiencies
Lack of essential nutrients
exhibit specific symptoms
dependent on
function of nutrient
dependent on
solubility of nutrient
Slide9Mineral deficiency symptoms depend not only on the role of the nutrient but also on its mobility within the plant. If a nutrient moves about freely, symptoms will show up first in older organs because young, growing tissues have more “drawing power” for nutrients in short supply. For example, magnesium is relatively mobile and is shunted preferentially to young leaves. Therefore, a plant starved for magnesium will show signs of chlorosis first in its older leaves. The mechanism for preferential routing is the source–to–sink translocation in phloem as minerals move along with the sugars to the growing tissues. In contrast, a deficiency of a mineral that is relatively immobile will affect young parts of the plant first. Older tissues may have adequate amounts, which they are able to retain during periods of short supply. For example, iron does not move freely within a plant, and an iron deficiency will cause yellowing of young leaves before any effect on older leaves is visible.
Deficiencies of nitrogen, phosphorus, and potassium are most common. Shortages of micronutrients are less common and tend to occur in certain geographic regions because of differences in soil composition. The symptoms of a mineral deficiency are often distinctive enough for a plant physiologist or farmer to diagnose its cause
Slide10Magnesium deficiency
Symptomschlorosis = yellowing of leavesWhy?
What is magnesium’s function?
Take 2
fertilizer pellets
& call me in
the morning
Slide11Chlorophyll
Why does magnesium deficiency cause chlorosis?
The chlorosis shows up in older leaves first, because plant moves Mg
+
to newer leaves. Why?
Slide12The 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
Agronomists
really dig dirt
!
Slide13Importance of organic matter
Topsoilmost important to plant growth
rich in
organic matter
humus
decomposing organic material
breakdown of dead organisms, feces, fallen leaves & other organic refuse by bacteria & fungi improves soil texturereservoir of minerals
organisms1 tsp. of topsoil has ~5 billion bacteria living with fungi, algae, protists, insects, earthworms, nematodes
So don’t rake
your lawn or
bag your leaves
Slide14Soil 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 cattlebare ground exposed to wind erosion in winter
drought
Slide15Soil health as a global issue
Soil conservation & sustainable agriculture
maintaining healthy environment
sustainable production of food supply
economically viable farming industry
contour plowing
crop rotation
“A sustainable agriculture does not deplete soils or people.”
– Wendell Berry
cover crops
Slide16Slide17Fertilizers
“Organic” fertilizers
manure, compost, fishmeal
“Chemical” fertilizers
commercially manufactured
N-P-K (ex. 15-10-5)
15% nitrogen10% phosphorus 5% potassium
What are the
political, economic,
environmental
issues?
Your next Current event!
Slide18Nitrogen uptake
Nitrates
plants can only take up nitrate (NO
3
-
)
Nitrogen cycle by bacteriatrace path of nitrogen fixation
!What will the plant use N for?
root
Slide19Soybean root nodules
N fixation by
Rhizobium
bacteria
symbiotic relationship
with bean family (legumes)
Slide20Increasing soil fertility
Cover cropsgrowing a field of plants just to
plow them under
usually a legume crop
taking care of soil’s health
puts nitrogen back in soil
erosion control, too
A farmer…
outstanding
in his field?
Plow it under?
Why would you
that?
Slide212006-2007
Some plant oddities…
Slide22Parasitic plants
tap into host plant vascular system
Indian pipe
Mistletoe
Slide23Plants of peat bogs
High acid environmentmost minerals & nutrients bound up & are not available to plantsmust find alternative sources of nutrients
Slide24Carnivorous
plants
Are they really carnivores?
Pitcher plant
Venus fly trap
Sundew
Slide25Pitcher plant
Slide26Uses of peat
Slide27Any Questions??
Slide28Review Questions
0
Slide291. The inorganic compound that contributes most of the mass to a plant’s organic matter is
*
H
2
O.
CO
2.NO32
.O2.
C
6
H
12
O
6
.
Slide302.
You are conducting an experiment on plant growth. You take a plant fresh from the soil and it weighs 5 kg. Then you dry the plant overnight and determine the dry weight to be 1 kg. Of this dry weight, how much would you expect to be made up of inorganic minerals?50 grams
500 grams
1 kg
4 kg
5 kg
Slide31we can rule out C, D , and E and because the dry weight of any plant is going to be mostly cellulose ( a polymer of glucose) we can pretty much be assured half of the dry weight is not going to be from inorganic minerals and ions. The only choice that makes any sense at all is 50grams. No calculations needed
Slide32This figure shows the results of a study to determine the effect of soil air spaces on plant growth. Use these data to answer the following question.
Slide333. The best explanation for the shape of this growth response curve is that
the plant requires air in the soil for photosynthesis. the roots are able to absorb more nitrogen (N
2
) in high levels of air.
most of the decrease in weight at low air levels is due to transpiration from the leaves.
increased soil air produces more root mass in the soil but does not affect the top stems and leaves.
the roots require oxygen for respiration and growth.
Slide344. Carnivorous plants have evolved mechanisms that trap and digest small animals. The products of this digestion are used to supplement the plant's supply of
energy.carbohydrates.
lipids and steroids.
minerals.
water.
Slide35Are some essential elements more important than others? Explain.
No, because even though macronutrients are required in greater amounts, all essential elements are necessary for the plant to complete its life cycle.
Slide36Can a single leaf be used to diagnose all of a plant’s mineral deficiencies? Explain.
a. No, because deficiencies of nutrients that are more mobile show up first in older leaves, whereas deficiencies in nutrients that are less mobile show up first in younger leaves.