nitrogen and sulphate assimilation presentation

8/8/2019 Nitrogen and Sulphate Assimilation Presentation

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Nitrogen CycleNitrogen CyclePresented by : Wiwik simanjuntak


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NITROGENNitrogena chemical element that has the symbol N.

Atomic number of 7 and atomic mass14.00674 u. Elemental nitrogen is a colorless,odorless, tasteless and mostly inert diatomic

gas at standard conditions, constituting

78.08% by volume of Earth's atmosphere.

Discovered by Scottish physician Daniel Rutherford, in 1772.


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F igure 1Nitrogen cycle

Source


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IntroductionSource of Nitrogen:

NO3 (Nitrate);

Most of the plant.Source: Industrial burn, Volcanic activityand F orest burn

NH4 (Ammoniac); F or Corniferae and Poaceae family.Source : Ozone by thunder light and UV radiation.


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F orms of Nitrogen

Urea CO(NH 2)2Ammonia NH 3 (gaseous)

Ammonium NH 4Nitrate NO 3Nitrite NO 2

Atmospheric Dinitrogen N 2Organic N


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Nitrogen is a key element for

amino acids

nucleic acids (purine, pyrimidine)cell wall components of bacteria(NAM).


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Nitrogen Cycles

Ammonification/mineralizationImmobilization

Nitrogen F ixationNitrificationDenitrification


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Ammonification or

Mineralization

R- NH2

NH4 NO 2

NO 3NO 2

NO

N2O

N2


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Mineralization or Ammonification

Decomposers: earthworms, termites, slugs,snails, bacteria, and fungiUses extracellular enzymes initiatedegradation of plant polymersMicroorganisms uses:Proteases, lysozymes, nucleases to degrade

nitrogen containing molecules


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ImmobilizationThe opposite of mineralizationHappens when nitrogen is limiting in theenvironmentNitrogen limitation is governed by C/N ratioC/N typical for soil microbial biomass is 20C/N < 20 Mineralization

C/N > 20 Immobilization


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Nitrogen FixationNitrogen FixationPresented by : Mawaddah


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Nitrogen F ixation

R- NH2

NH4 NO 2

NO 3NO 2

NO

N2O

N2


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Nitrogen fixation

This is the first step in the nitrogen cycle and itinvolves the reduction of atmospheric nitrogen gas(N2) to ammonia (NH 3).

This can only be done biologically by a small and highlyspecialized group of microorganisms.

The enzyme Nitrogenase catalyzes the reduction of diatomic nitrogen gas (in the atmosphere) to ammonia.

N 2 + 6 e- + 8H+ ---Nitrogenase -- & F e, Mo 2 NH 3 + H2


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Nitrogen fixing organisms

All the nitrogen-fixing organisms are prokaryotes(bacteria).

Some of them liveindependently of otherorganisms - the free-living nitrogen-fixing bacteria.

Others live in intimatesymbiotic associations withplants or with otherorganisms (e.g. protozoa).


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Microorganisms fixing AzobacterBeijerinckiaAzospirillumClostridiumCyanobacteria

Require the enzymenitrogenaseInhibited by oxygenInhibited byammonia (endproduct)


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Bacterial F ixation

Occurs mostly in salt marshesIs absent from low pH peat of

northern bogsCyanobacteria found in waterloggedsoils


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Nitrogen fixing associations

Nodulation The nodule is ahighly organisedstructure withmembranous sacscontaining colonies of thebacteria.

It is in directconnection with

the vascularsystem of theplant.


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Nodulation

Once the nodule is established, the differentiatedbacteria (they become non-motile bacteroids) living in

the infected plant cells, reduce atmospheric nitrogen to ammonia which is excreted to the plant cell and is,in turn, assimilated to organic nitrogen (proteins andamino acids) by the plant.

The plant provides the bacteroid with carbonskeletons (photosynthate) which are required by

Rhizobium.


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Nodulation This symbiosis is a specific process, a certain speciesof Rhizobium can only nodulate a certain type of

legume, for example: R. etli nodulates beans (Phaseolus), R. meliloti nodulates alfalfa (Medicago).

The bacterial nitrogenase enzyme complex isresponsible for the reduction of gaseous N 2 toammonia.

Different nitrogenase enzyme systems have beenfound in different microorganisms.


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Nodulation

Associations are also made with certain woody plants. This occurs via Frankia, which is a genus of thebacterial group termed Actinomycetes.

Included in this group are the common soil-dwelling Streptomyces species which produce many of theantibiotics.

Frankia species are slow-growing in culture, andrequire specialised media, suggesting that they arespecialised symbionts.


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ENZYMATIC MECHANISM OF NITROGEN FIXATION

6M gADP + 6 P i


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Enzymatic Mechanism of Nitrogen

F ixation The reduced ferredoxin, which supplies electrons for this process is generated by photosynthesis,respiration or fermentation.

F unctional conservation between the nitrogenaseproteins.

Nitrogen fixation occurs when the F e protein of one

species is mixed with the Mo- F e protein of anotherbacterium, even if the species are very distantlyrelated.

The nitrogenase enzyme complex is highly sensitive tooxygen.


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Denitrification

R- NH2

NH4 NO 2

NO 3NO 2

NO

N2O

N2


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Denitrification

Removes a limiting nutrient from theenvironment

4NO 3-

+ C 6H12O 6 2N2 + 6 H20Inhibited by O 2Not inhibited by ammonia

Microbial reactionNitrate is the terminal electronacceptor


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Assimilation of Assimilation of Nitrate Ion andNitrate Ion and

AmmoniumAmmoniumPresented by : Sri Hayuni


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F igure 2.

Plant absorb the nitrogencompound from the root inform of ammonium andnitrate.


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Nitrate Assimilation Absorb nitrate or ammonium ions from thesoil via root hairs.Have a mutualistic relationship with

rhizobia.Some nitrogen is assimilated in the form of ammonium ions directly from the nodules.

NitrogenCycle N2(g) -------> NH4

+(aq) -------> NO2

-(aq) -------> NO 3

-(aq)

OxidationNumber of

N0 -------> -3 -------> +3 -------> +5

Reaction Type

reduction oxidation oxidation


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Nitrate Assimilation

Some plant, can synthesis organic nitrogenin root by it self.NO3 Amino Acid and Amida

Plant: Betulaceae, Casuarinaceae,Eleagnaceae, Moraceae, Leguminosae( F abaceae) and Myricaceae families.

Plant root term called Cluster Root or Proteoid Root.

Can symbiotic to fixed atmospheric N 2.


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Another plants, need the supply of treetopsfor get nitrogen

supply.Example: Xanthiumstumanium.Almost not fixativeNO3 at all.

Nitrate Assimilation

Figure 4. Xanthium stumanium.See book, page 210 for comparinganother plants.


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Nitrate AssimilationNitrate Reduction Process

2 steps reactions:.

F irst Step:

Catalyze by: nitrate reductaseenzyme.Occurs in cytosol.

O H NAD NO NADH NO reductase Nitrate

2223 p


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2 steps of reaction:,

Second reaction:Nitrite convert become ammoniumion.Occurs in: Chloroplast at leaf

Protoplastida at root Require 6 electrons from H2O.


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2 steps of reaction:,

Second reaction:)(665.1)(63 22

3

2p F e Fd H Olight F e Fd O H

O H F e Fd NH H F e Fd NO 23

4

2

22)(68)(6 p

. R 1

. R 2

O H O NH L ight H O H NO 22422 25.123 p


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Nitrate AssimilationC onverting Become Organic C ompound

Ammonium actually poisonous, inhibit ATP formation.

UncouplerConverted again into another organiccompound.

GlutamineGlutamine syntase enzyme Asparangin Asparagin syntase enzyme


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Nitrate AssimilationC onverting Become Organic C ompound

Glutamine; storagenitrogen in tuber.

E.g. Potato, beet,carrot.

Fo rmed: Glutamateacid and NH4 fr o mpr o teindec o mpo siti o n.

F igure 5.

Beet tuber rich c o nsisto f glutamine


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Nitrate Assimilati o nC onverting Become Organic C ompound

Asparagin; st o rage

nitr o gen f o und inlegumes, nut, seed,so y, wh o le grain plant.

No dule o f R oo tat legumes


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NitrogenNitrogen

TransformationTransformationPresented by : Devi Wani


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Nitrogen TransformationD uring Seed Germination

O Protein reserve keeps at the aleuronlayer of the seed .

O Also storage place for fosfat,magnesium and calsium.

O Need for the germinate the seed.O Process start by imbibitions of theseed, and catalyze the enzyme for seed

germination


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Protein reservelining at aleuron layer


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O Process:O Protein in Aleuron layer hydrolyzed by

proteinase and peptidase enzyme to beconverted become amino acid and amida.O Membrane of Aleuron fuse to form

tonoplast surrounding the vacuole.O Some amino acid and amida start to formnew protein which being transfer to the

root and tip of tree.O Protein need for cell division in

meristematic


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Nitrogen TransformationD uring Plant Growth

O Most nitrogen formed as protein.O At leaf nitrogen concentrated in

chlorophyll.O There is also nitrogen storage at seed.O Nitrogen at leaf, transferred to aleuron

layer during seed formation.O Required a lot of Rubisco enzyme(Photosynthesis enzyme), causes decreasing

photosynthesis rate during seed formation.Called as Self Destroying


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O At wheat plants, 85% nitrogen looses during seed formation.

O Nitrogen being transferred to thereproductive system.O At annual wet plant, nitrogen transferred

again to root and tip tree after nitrogen

required in seeds finish.O So nitrogen still available at the nextreproductive seasons.


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O Nitrogen storage mostly at fruits and seeds.O F ruits get nutrient from the storage of

nitrogen which transferred by phloem from the axial leaves.O Apple plants, looses half of nitrogen reserve

from the leaf at that process.


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S ulphateS ulphate

AssimilationAssimilationPresented by : remli nelmian


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Sulphate assimilationSulfur is macronutrients required by plants.It is found in organic form in amino acids like Cysteine andMethionine and in a variety of metabolites. In inorganic form :Sulphate ion (SO 42- ) in soil

SO42- is a major anionic component of vacuolar sap; therefore,it does not necessarily enter the assimilation stream

Gaseous sulfur dioxide (SO 2) is readily absorbed andassimilated by leaves, but it is significant as a nutrient sourceonly in industrial areas with air pollution.


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Sulfate ion taken up by the roots is the major source for growth; it isreduced to sulfide and then can bemetabolized further andincorporated into cysteine.

SO 42- + ATP + 8 e - + 8 H + S2- + 4 H2O + AMP + PiP

Sulphate ion reduction take placein roots and tip of plant, some

transported by xylem to leaf insulphate ion form


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Assimilation stepThe first step of assimilation of SO 42- isSO 42- reaction with ATP produce Adenosin-5-Phosphosulphate (APS) and

Phirophosphate (PiP).This stage catalyze by Sulfurilase ATP. PiPhydrolyze to two iP by Phirophosphataseenzyme and then used in Mitochondria orChloroplast for ATP regeneration.


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nitrogen and sulphate assimilation presentation

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