Nutrient Balance
NRES 406/606
Spring 2013
hernandez.leo@cabnr.unr.edu
The study of how plants absorb and assimilate
inorganic compounds is called Mineral
Nutrition and it is specially important in
agriculture and environmental protection
http://www.biology-blog.com/images/blogs/10-2007/fertilizer-15101.gif
http://serc.carleton.edu/images/microbelife/topics/map_of_gulf_of_.jpg
• Higher plants are autotrophic organisms
http://www.sheppardsoftware.com/content/animals/kidscorner/images/fo
odchain/fullchain.gif
• Higher plants are autotrophic organisms
– Synthesize organic components out of the inorganic
elements found in their surroundings
http://www.sheppardsoftware.com/content/animals/kidscorner/images/fo
odchain/fullchain.gif
• Most of the nutrients
plants need are taken
up by the roots directly
from the soil solution
• Most of the nutrients
plants need are taken
up by the roots directly
from the soil solution
http://www.savingwithshellie.com/wp-content/uploads/2011/01/Vitaminwater.jpg
CHO
• ~85% of plant dry matter is made of
– C (Atmosphere)
–H
–O
http://spark.ucar.edu/sites/default/files/images/large_imag
e_for_image_content/co2_molecule_720x400.gif
http://www.lenntech.com/images/Water%20molecule.jpg
What are those inorganic elements?
• Are all these elements equally important for
plants?
What are those inorganic elements?
What are those inorganic elements?
Essential
Elements
Essential elements
• Those that have a clear physiological role.
• If plants receive all of these plus water and
sunlight they will synthesize all the
compounds needed.
• Based on the relative abundance in the plant…
• Macronutrients
– >1%
– N,K, Ca, P,S, Mg
• Micronutrients (Trace elements)
– <1%
http://www.stewardcoaching.com/wordpress/wpcontent/uploads/2012/01/quality_vs_quantity.jpg
• Nutrient concentration
is not constant among
different plant
structures.
Why leaves?
• Nutrient concentrations in the soils ultimately
determine the acquisition and concentration
in plants.
• Some soils have high concentration of specific
elements, like heavy metals.
– Au, Ag, Ni, Al Hg
Accumulator plant
In some cases, plants growing in
soils with high concentration of a
particular element can accumulate
large concentration of that element
without apparent side effects.
Equisetum
• The atmosphere is the mayor source of N
– Biotic dinitrogen fixation
– Deposition
• Some cations may come from particulates
traveling form other regions or from industrial
pollution
– Na (sea salt in coastal regions)
– Fe & P from Africa
Nature
• Nutrient recycling is the
major source of soluble
nutrients
http://polaris.umuc.edu/~meaton/edtc620/omed/images/decomposit
ion.jpg
• Nutrient recycling is the
major source of soluble
nutrients
Microbial Activity
http://polaris.umuc.edu/~meaton/edtc620/omed/images/decomposit
ion.jpg
1
2
3
4
2. How the element is found in the soil
4. For that plants take up the element
8. Within the plant
5
6
7
8
3. How does it change from 2 to 4
5. How does the element exist w/in the
plant
1
2
3
4
5
6
7
8
• Most of N in soil is found organically
bound
• Microbial activity is required to make it
available fro plants
• Element that plants need the most
• N deficiency rapidly affects plant growth
• chlorosis
http://hort.ufl.edu/database/images/nutdef/thy9529_M.jpg
P
• Integral component of plant cell
• Used in energy metabolism
• Stunt growth and yellow foliage
S
• S and N are constituents of many
proteins.
• Deficiency symptoms are very similar to
those of N.
http://pics.davesgarden.com/pics/2008/12/20/dar
ius/c498d5.jpg
K
• Inorganic form
• Found as free cation in plants (Osmotic
potential)
• Activates many enzymes involved in
photosynthesis
http://www.ipni.net/ppiweb/gseasia.nsf/$webindex/914E7F33D86
6E03848256E8900362252/$file/%23601%20legume%20lcp%20k%
20def.jpg
http://upload.wikimedia.org/wikipedia/comm
ons/thumb/5/57/Chlorophyll_c2.svg/220pxChlorophyll_c2.svg.png
Mg
• Enzyme activation
• Synthesis of DNA and RNA
• Deficiency causes intervein chlorosis
Ca
• Synthesis of cell wall
• Cell Division (mitotic spindle)
http://www.enst.umd.edu/files
/PicsWeil/MagnesiumPoinsetti
aRRW.jpg
http://upload.wikimedia.org/wikipedia/commons/thumb/2/2e/Blosso
m_end_rot.JPG/220px-Blossom_end_rot.JPG
Fe
• Component of enzymes involved in e- transport
• Intervenous chlorosis
http://cleatordesigns.files.wordpress.com/2
011/03/032409-hartman-rhodo-fedeficiency-kaiser-h17-73.jpg
Why a chelate?
http://www.drt.com.tr/doctoferro/images/chelate.jpg
All micronutrients are found as inorganic compounds in the soil
http://middletownhighschool.wikispaces.com/file/view/plantcell450.jpg/98794271/plantcell450.jpg
• N, P. S, Fe and Mg are directly
involved in metabolic activities
• Ca and K are inorganic ions but
are biological active ( osmotic
potential)
• Leaves are the most common
place of nutrient accumulation
within plants (vacuole)
• Except Cl, all other
micronutrients are stored as
organic forms
Nutrient Uptake
1. Dissolved nutrients are
taking in with water
due to the continuous
movement of water
driven by transpiration
SPAC
Nutrient Uptake
2.Proton pump: H+ excreted out
of cells affect the absorptivity
of ions in the soil and release
them into the soil solution.
By releasing H+ and HCO3- from the roots,
plants promote ion exchange at the
surface of clay particles. (Root Exudates)
http://extension.missouri.edu/explore/images/mg0004art04.jpg
Nutrient Uptake
3. Weathering of the soil:
Roots can release
compounds that lower
the pH breaking down soil
particulates.
http://www.drt.com.tr/doctoferro/image
s/chelate.jpg
http://it.pinellas.k12.fl.us/Teachers/madeirosa/images/48655D05E7824170A64E008894255590.gif
Nutrient Balance
Episode II
Nutrient uptake
– Passive
• Following a gradient
– Active
• Against a gradient
http://www.funtasti.com/pdata/t/l-31.jpg
Ion Uptake into the cell
• Passive transport
– Transport proteins
• Channels
– (Selective) pores
– Size and Density
• Carriers *
– Substance being transported binds to the carrier
– Conformational change
– Dissociation
Ion Uptake into the cell
• Active transport
– Energy depends on photosynthesis and respiration
– ATP-ases function as proton pumps
• Electrochemical gradient
– Present in plasmalemma and the tonoplast
Proton Pump
http://avonapbio.pbworks.com/f/electrogenic.jpg
H+ Pump
Electrochemical
gradient
Uniports
Cotransporters
Uniports:
•Integral proteins
•Charge Specific
•In the tonoplast
these could be ionspecific.
•Low affinity
Cotransporters:
•Integral proteins
•Active transport
•Require H+ pump
•High affinity
•One way & Two ways
Cotransporters
Response to Nutrient Supply
• Michaelis-Menten
• Uptake increase in
response to supply until a
maximum value is
achieved (Imax)
• Km: nutrient
concentration at which
• Imax/2 is reached
http://depts.washington.edu/wmatkins/kinetics/mm1.gif
Km as a measure of Affinity
• Km is a measure of the capacity of the root to
use nutrient at low concentrations.
• Km Affinity
• Km
Affinity
L.A.S
H.A.S
H.A.S
L.A.S