Oxidation-reduction rxn: Ps, Rd, Nitrate reductase etc.
Immoble
Morphological ∆ from def: stategy 1 (dicots) protieod roots and more transfer cells in rhizoderm
Physiological ∆ from def: strategy 2 (grasses) enhance synthesis of PS and enhanced release of PS
Mg
Central atom of chlorohyll
Mobile
Intervail chlorosis
Mn
Important in PSII
Immobile
decrease Ps and growth
gray spots in small grains
Zn
In enyzmes: alcohol dehydrogenase
Immoble
intervail cholorsis, streaking and weathering
P
Helps trigger enzymatic reactions as energy and has a structural role in lipid bi-layer
moble
Purple corn
K
Stomata regulation
moble
marginal necrosis
S
Used for charge balance in the cell and needed for nitrogenaous enzyme
Moble
Kind a looks like N, yellowing leaves
N
Amino acids, protiens
moible
inverted V in corn ears
Which function is generally non-subsitutaible
metabolic function
Special deficiency of K
build up of smaller building blocks for enzymes
it helps assemble them
Structure of ATP
Special P deficency
Turn dark-blue
cell walls can't extend so concentrated chlorophyll
Special S deficency
increased level of aa because protien systhesis is inhibited
Which elements are important osoticants
K, Na, Ca & Mg
Which pool is more highly buffered
metabolic/osmotic?
metabolic?
What form of N is stored in the plant
NO3-
Which form of N is prefered
NH4+
doesn't need to be reduced
What N sources result in the highest growth rate
NH4+ and NO3-
balcance pH of the rhizophere
What are the two compoents of nitrogen reduction and where do they occur
Nitrate reductace (NO3- -> NO2-)
In the cytoplasm
Nitrite reducance (NO2- -> NH4+)
In chloroplast
Which tissues have the most Nitrate reduciton activity
leaves
need the light reaction to get rid of NO2-
What factors affect NO3- conentration of transpiring plant?
uptake
rate of transpiration
What controls location of root or shoot NO3- reduction
generally happens in the roots b/c it is low energy and if concentration in soil is low
if concentration in soil is high then it happens more in the shoot
How is NH4+/NH3 detoxified in the plant?
It is assimilated by GS-GOGAT to make amino acids
GS: Glutamine sythetase- NH4+ + glutamate to get glutamine
GOGAT: Glutamate sythase- glutamate + 2-oxoglutarate to get 2 glutamates
Major types of microbial strategies for N2 fixing how much N fixed (kg N /ha/ year)
Symbiotic: Rhizobium, sucrose from host, nodules (50-400)
Associative: Azotobacter, energy from root exudates (10-200)
Free-living: Azotobacter, eat plant residue (1-2) or autotrophs (10-80)
Infection process for symbolic N fixation
1. Plant root give off elicitors of Nod gene expression
2. Bacteria releases Nod factor - cause inflection thread to form // root hair curve
3. Infection thread grows into root
4. thread releases bateria cells into cortex
5. forms nodules
What two parts of BNF need carbohydrates
Nitogenase enzyme needs 16 ATPS
Sucrose for the electron transport chain
Where is O2 needed and not good in BNF
Cytochrome oxidase uses O2 to make ATP
but need to keep O2 away from Nitrogenase complex.
Which elements are essential for the nitrogenase enzyme
Mo and Fe
What factors control BNF potential
photosynthsis rate
N supply in the soil - NO3 depresses nodulation
Crop demand for N (feedback/build up)
adequte P and Fe needed for nodulation
water stress
different temperature optimums
basic pH (Ca) for infection thread
How does K effect stomatal movement and why?
causes them to move
K is pumped into the cytoplasm - to open
water follows to reduce concentration
to close is fast, K to vacole w/o ∆ pH (pump out H+ and in Cl- ??
3 reasons why non-legumes grow best on a combination of NO3 and NH4 as N source
- charge balance
- Too much energy to reduce NO3 if that only taken up
- both are used in chlroplast to make products for amino acids (Nitrogen assimulation)
- keeps Mo supply need low
3 micronutrients that help break down free radicals
Cu Zn, Fe for SOD- superoxide dismutases
they can accept the extra e- on O2- so that it does not attack lipids, protiens etc.
ID 3 elements that serve as redox reagents
for one explain a specific purpose
Fe, Cu, Mo
Cu- is in plastocyanin for e- transport in PSI
Why do Zinc deficent plants have high concentrations of Cl and B in their leaves
If low Zn -> low Zn SOD -> membranes damaged -> rapid uptake of Cl and B
High P content can cause phytic acid build up which ties up Zn
Four groups of functions
1. Structural componets of biological compound and intermediates of metabolism
2. Enzyme activators
3. Redox reagents
4. Uncertain function
Why is plant S status important for preventing Cu and Zn deficiency
S helps create photochelatins which bind heavy metal like Cu and Zn
two examples of how SO4 assimilartion differes form NO3
SO4 doesn't have to be reduced- NO3 does
Once NO3 is reduced it stays that way, where SO4 is useful because it can go both ways
which takes more K - Photosynthesis or RU-BP?
Ru-bp
but both need
What can substitute for K osmotic role
Ca
Too much K can cause stomtal difficulties
true because need concentration gradent
Photosynthesis v. Leaf water potental under very low, suffecent and high K
Ca distribution in cell: 2 high and 1 low location
High: Vacuole and Endoplasmic reticulum
Low: in cytoplasm
Photosiderophore
non-protien amino acid
made in response to lack of Fe in grasses
pumped out, picks up Fe 3+ and brings it in together
Transfer cells
Used by dicots to increase uptake of Fe2+
More made in the rhizoderm-> outer most layer of corticle cells in the root
What toxicity problems are enhanced by acid soils
Fe, reduced by availble H+
Zn
Mn
What defecincy problems are enhanced in acid soils
Zn
Mo
Cu: role, mobile deficiency
main functions redox capablities
immoble
low carbohydrated abailibty because reduced PSI and PSII, sterility not enough carbohydrate
Interactions of Mo and NH4 NO3
Mo requirement is low if N requirement is low
If higher in NH4 increase Mo requirement for legumes opposite for non-legumes
If higher in NO3 don't need Mo for legumes opposite for non-legumes because don't need nitrate reductase
Probable roles of B in the plant
don't really know, no radio tracers and difficult chemistry
NOT enzyme activator,
cell wall synthesis and maintenance
pollen tube formation
order of vascular tissue
B uptake active or passive?
Active b/c vary much
folair application is good b/c moves with the transpiration stream
Ni info
needed in urase enzymne to work and break down urea
Cl
good ion for isomotic potential balance
Why? P application reduced symptoms of N deficiency in a legume?
Because P is needed in high rates for nodule development and high rates of N2 fixation
16 ATPs for Nitroganse enzymne complex
S application reduced symptoms of Cu toxicity?
Why?
Cu will complex with sulfhyral groups and not be avalible for uptake
Switching from NH4+ to NO3- as the N source increases the proportion of N in protein form
(i.e. increases protein synthesis) in a non-legume and enhances the starch
content of a tuber. -Why?
reduction happens in the shoots which is more effecient
so more starch
A sewage sludge application induces Ca, Fe and / or Mg symptoms on a variety of different sites?
all 2+ get tied up in OM
Plants grown on a field receiving optimal macronutrient supplies have smallish leaves with very high P, Cl, and B concentrations.
Why?
Zn deficiency
High P = ties up Zn in phytic acid
High Cl and B uptake because membranes are damaged from lack of Zn SOD to take care of super oxide
Storage form of P
phytin - 6 phosphate groups + C and is expensive so not luxury consumed
vacoule
What caueses protiod root production
N, Fe, and P deficiency
How is Sulfate similar/ different to Nitrate assimilation
Both leach in the soil
both must be reduced
N can't go back
What is phytochelatin
polipeptieds high in cystine important in binding heavy metals
S is stored in Sulfate so it is the best way to assess S status
true
Ca has micro and macro functions
micro- signaling/ secondary measanger in the cytoplasm and enzyme activiator of sucrose
Macro- essential for membrane permiablity
Mg is also distributed that way
What is Ca modulin?
an enzyme that is activitated by Ca
allows calmodulin expression
Why are root uptake rates down with Mg defeciency
because PS is negatively impacted root growth is down
Mg can can replace K in osmoitc role
Discribe the function of Ca where it is in high concentration
Middle lamella: for stabilty and struture, can be subsitiuted by Mg or Al not very well
Exterior of plasma membrane: bridges phosphate and carboxylate groups, can be subusituted with Na causes salinity problems
Vacuole: osmo-regulation, K well
Why is concentration of Ca low in cytoplasm?
binds with Pi and precipates
competition with Mg
needs to be low for messaging and enzyme activator role
