Lesson 1 Introduction and Crop Growth Analysis AGR3301 Sem2 MAR 2022.pdf

Introduction and Crop Growth Analysis

1. CROP PHYSIOLOGY
(FISIOLOGY TANAMAN)
AGR3301

3. Introduction: CROPor PLANTPHYSIOLOGY?
•Asplantsgrowtomaturity,thecellsareproduced,divide,grow&become
specializedorganslike:
•Stems,leaves,roots,flowers,fruits,seeds.
•CROPPhysiology–Thestudyofhowtheseorgansfunctionandthe
complexchemicalprocessesthatpermitthecroptolive,growand
reproduce.
•Itisthescienceconcernedwith(i)Processesand(ii)Functions,the
responsesofcropstoenvironmentandthegrowthanddevelopmentthat
resultsfromthere
•TheoverallgoalofCropPhysiologyistoevolveadetailedand
comprehensiveknowledgeofallthenaturalphenomenathatoccurin
livingplantsandthustounderstandthenatureofplantgrowth,
developmentandproductivity.Manyaspectsofpracticalagriculturecan
benefitfrommoreintensiveresearchinplantphysiology.
Plantsaremulticellularphotosyntheticeukaryoticlife-formsbelongingto
kingdomPlantae.Cropsareplantsgrowninlargequantitiesforfoodorother
commercialpurposes(involveprofitsandsubsistence).Allcropsareplants,
butnotallplantsarecrops

4. (i) Processes :
Processes means natural event/ sequence of events. Examples of
processes that occur in crops are:
♦Photosynthesis ♦Respiration
♦Ion absorption ♦Translocation
♦Transpiration ♦Stomatal opening and closing
♦Assimilation ♦Flowering
♦Seed formation and ♦Seed germination
To described and explain the crops processes is the main task or the first
task of crop physiology.

5. (ii). Function:
Functionmeansnaturalactivityofacellor
tissue,ororganorachemicalsubstance.
So,thesecondtaskofplantphysiologyisto
describeandexplainthefunctionofan
organ,tissue,cellandcellorganelleinplants
andthefunctionof eachchemical
constituent,whetheritmaybeanion,
moleculeoramacromolecule.
Bothprocessesandfunctionsaredependent
ontheexternalfactorsandaremodifiedby
theexternalfactorssuchaslightand
temperature.
Finally,sincethesetwofactorsaremodified
bytheexternalfactors,thethirdtaskofcrop
physiologyistodescribeandexplainhow
processesandfunctionsrespondtochange
intheenvironment.

6. Major Parts of a Plant.
Remember, once grow this
plant a lot for money, you
call it crop ok ☺

7. Growth,
Development,
Differentiation.
Get it right

8. Growth
Growthis the irreversiblechange in size of cells and plant organs due to
bothcell divisionandenlargement.
Growth can bedeterminate—when an organ or part or whole organism
reaches a certain size and then stops growing—orindeterminate—when cells
continue to divide indefinitely.

9. Development
Developmentistheprogressionfromearliertolaterstagesinmaturation,
e.g.afertilizedeggdevelopsintoamaturetree.
Itistheprocesswherebytissues,organs,andwholeplantsareproduced.It
involves:growth,morphogenesis(theacquisitionofformandstructure),
anddifferentiation(identityspecialisation).
Theinteractionsoftheenvironmentandthegeneticinstructionsinherited
bythecellsdeterminehowcropdevelops.

10. Differentiation
Differentiationistheprocessin
whichgeneralizedcellsspecialize
intothemorphologicallyand
physiologicallydifferentcells.
Sinceallofthecellsproducedby
divisioninthemeristemshave
thesamegeneticmakeup,
differentiationisafunctionof
whichparticulargenesareeither
expressedorrepressed.
Thekindofcellthatultimately
developsalsoisaresultofits
location:Rootcellsdon'tformin
developingflowers,forexample,
nordopetalsformonroots.

11. CROP
GROWTH ANALYSIS

13. If someone sow a seed in garden or in a pot, after few days
he/she would find a tiny seedling coming out from the seed.
As days pass, the
leavesincreases,
producesflowers
tiny
and
and
seedling grows in size, the number of
later,itgrowsintoamatureplantand
fruits.ThisistheprocessofGrowth
and Development.

14. GROWTH AND DEVELOPMENT a

15. GROWTH
Growth is an irreversible increase in mass,
weight or volume of a living organism,
organ or cell.
Growth is an advancementtowards
maturity.
Growth is attained mainly by net
photosynthesis (after respirationloss has
been accounted for).

16. STAGES OF CELLULAR GROWTH
Growthisnotasimpleprocess.Itoccursin
meristematicregionswherebeforecompletionofthis
process,ameristematiccellmustpassthroughthe
following3phases.
Theyare:
(i)Celldivision(FormationPhase):Thenumberof
cellsincreasesduetomitosis.
(ii)Cellenlargement(ElongationPhase):Thesizeof
individualcellincreasesaftercell
divisionduetoincreaseinthevolumeofits
protoplasm
(iii)Celldifferentiation(MaturationPhase):Inthis
stage,structureofthecellschangestoperform
specificfunctions.Andsimilartypeofcellshaving
same
functionsformagroup,whichisknownastissue.

18. Growth curve (Sigmoid Curve) :
Typical growth pattern of an annual plant is divided into three phases.
1. Lag periodof growth: during this periodthe growth rate is quite slow because it is
the initial stage of growth.
2. Log periodof growth: during this period, the growth rate is maximum and reaches
the top because at this stage the cell division and physiological processes are quite
fast.
3. Senescence period or steady state period: during this period the growth is
almost complete and become static. Thus, the growth rate becomes zero.

19. MEASUREMENT OF GROWTH
After knowing the different phases of growth let us know
howto measuregrowth in plants.Growthin plantsbeinga
quantitativephenomenoncan be measuredin relationto
time.
It can be measured in terms of :
Increase in length or growth –in case of stem and root ,
Increase in area or volume –in case of leavesand fruits.

20. MEASUREMENT OF GROWTH
A. Freshweight:
Determinationoffreshweightisaneasyandconvenientmethodofmeasuringgrowth.For
measuringfreshweight,theentireplantisharvested,cleanedfordirtparticlesifanyand
thenweighed.
B. Dryweight:
Thedryweightoftheplantorgansisusuallyobtainedbydryingthematerialsfor21to
48hat70to80°candthenweighingit.Themeasurementsofdryweightmaygivea
morevalidandmeaningfulestimationofgrowththanfreshweight.
However,inmeasuringthegrowthofdarkgrownseedlingitisdesirabletotakefresh
weight.
C.Length:
Measurementoflengthisasuitableindicationofgrowthforthoseorganswhichgrowin
onedirectionwithalmostuniformdiametersuchasrootsandshoots.
Thelengthcan bemeasuredbyascale.The advantageofmeasuringlength isthatitcanbe
doneonthesameorganoveraperiodoftimewithoutdestroyingit.
D.Area:itisusedformeasuringgrowthofplantorganslikeleaf.Theareacanbe
measuredbyagraphpaperorbyasuitablemechanicaldevice.Nowadaysmodern
laboratoriesuseaphotoelectricdevice(digitalleafareameter)whichreadsleafarea
directlyastheindividualleavesisfedintoit.

21. GROWTH ANALYSIS
Growthanalysisisamathematicalexpressionof
environmentaleffectsongrowthanddevelopmentofcrop
plants.
Thisisausefultoolinstudyingthecomplexinteractions
betweentheplantgrowthandtheenvironment.
Thisanalysisdependsmainlyonprimaryvalues(Dryweights)
andtheycanbeeasilyobtainedwithoutgreatdemandon
modernlaboratoryequipment.

22. Objective of Growth Analysis
1.Toidentifyspatialandtemporalintegrationofallplantprocess.
2.Toknowtherateofdrymatteraccumulationvariesacrossthelifecycleofthe
crop.
3.Toquantifytheeffectsofenvironmentalinfluenceortoanalysethegenotypic
differencesbetweencropcultivars.
Drawbacksofgrowthanalysis
Inclassicalgrowthanalysissamplingforprimaryvaluesconsistofharvesting
(destructively)representativesetsofplantsorplotsanditisimpossibletofollowthesame
plantsorplotsthroughoutwholeexperiment.

23. COMMON PARAMETERS USED
GROWTH ANALYSIS
IN
1.ABSOLUTEGROWTHRATE(AGR)
2.CROPGROWTHRATE(CGR)
3.RELATIVEGROWTHRATE(RGR)
4.NETASSIMILATIONRATE(NAR)
5.LEAFAREAINDEX(LAI)

24. ABSOLUTE GROWTH RATE(AGR)
1
stThis concept wasgiven by West et all. in1925.
weight per plant.It indicates the
It aims at what
crop is growing
rate of increase of total dry
rate the crop is growing i.e.at whether the
at faster rate or slower rate than normal.
The simplest index of plant growth; a rate of change in size, an
increment in size per unit time. Most commonly applied to total
dry weight or total leaf area per plant.

25. Formula:
AGR=(W2-W1)/
Where
(t2-t1)
( in grams)
grams)
W1
W2
t 1
t 2
= Dry weight of plant at
= Dry weight of plant at
= time one ( in days)
=time two(in days)
time one
time ( in
Unit:
g(drymatter)/day
AbsoluteGrowthRate(AGR)Rateofincreaseindrymattergday-1 Indicatesthegrowthofplants

26. CROP GROWTH RATE(CGR)
1
stThis concept was described by D.J. Watsonin 1952.
The crop growth rate simply indicates the change in
matter accumulation over a period of time.
This expression can be used without any assumption
the form of the growth curve.
The formulae can be used to compare treatments
between and within experiments. They can even been
used when it is possible to make only two harvests.
Itisdefinedastheincreaseofdrymatterin
gramsperunitareaperunittime.

27. Formula of CGR
CGR=(W2-W1)/(t2-t1)
Where:
t 1
t 2
W1
W2
P
= time one ( in days)
=time two(in days)
= Dry weight of plant at time one ( in grams)
= Dry weight of plant at time ( in grams)
= Unit area
Unit :g/m2/unit time(day)

28. RELATIVE GROWTH RATE(RGR)
CoinedbyBlackmanin1919.
Definedastherateofincreaseindrymatterperunitofdrymatter
alreadypresent.Thisisalsoreferredas‘efficiencyindex’sincetherate
ofgrowthisexpressedastherateofinterestonthecapital..
Theincreasecanbeplottedasalogarithmicorexponentialcurvein
manycases.
RGRistheslopeofacurvethatrepresentslogarithmicgrowthovera
periodoftime.
Anexponentialgrowthrateisnotsustainableovertime.Thecurve
typicallyflattensout,representingsaturationinagrowthatacertain
pointoftime.
RelativeGrowthRate(RGR)Rateofincreaseindrymatter
perunitdrymatter
gg-1 day-1 Indicatestheproportionate
growth ofplantindependentof
theirsize

29. Formula:
RGR=(lnW2–lnW1)/(t2-t1)
Where:
In=natural logarithm
t 1
t 2
W1
W2
= time one ( in days)
=time two(in days)
= Dry weight of plant at time one (in grams)
= Dry weight of plant at time (in grams)
Unit:g/g/day
Rateofincreaseindrymatter
perunitdrymatter
gg-1 day-1Indicatestheproportionate
growth ofplantindependentof
theirsize

31. NET ASSIMILATION RATE(NAR)
The concept was 1stgiven by Gregory (1918).
NetAssimilationRate(NAR)Rateofincreaseindrymatter
perunitleafarea
gcm-2 day-1Indicatestheassimilatory
capacity ofplant
TheNARisameasureoftheamountofphotosyntheticproductgoinginto
plantmateriali.e.itistheestimateofnetphotosyntheticcarbonassimilatedby
photosynthesisminusthecarbonlostbyrespiration.
TheNARcanbedeterminedbymeasuringplantdryweightandleafarea
periodicallyduringgrowthandiscommonlyreportedasgramsofdryweight
increasepersquarecentimeterofleafsurfaceperweek.
Thisisalsocalledasunitleafratebecausetheassimilatoryareaincludesonly
theactiveleafareainmeasuringtherateofdrymatterproduction.

32. Formula:
NAR= (W2-W1)(log
Where
L2 –log L1)/(t2–t1)(L2–L1)
W1
W2
t1
t2
Iog
= Dry weight of plant
= Dry weight of plant
= time one ( in days)
=time two(in days)
=natural logarithm
at
at
time
time
one ( in grams)
( in grams)
L1 & L2 = Leaf Area
Unit : g(dry matterproduction)/m2/day

33. Leaf Area Index(LAI)
The concept was 1st given by Watson (1947)
Leaf area is important for photosynthesis . Itsestimation both
assimilating area and growth. For crop production leaf area
per unit land is more important area of individual plants.
Leaf area index is the ratio between leaf area to ground
area.
LeafArea Index(LAI) Ratioofleafareatothe
groundarea
- Proportionofgroundareacovered
by leaves

34. Optimum LAI
LAI increases slowly in early stage of crop growth and rapidly after seedling
stage.
As LAI increases, lightinterceptionismoreresultingin dry matterproduction.
However,at highLAI mutual shadingof leavesoccur andas shadedleaves
respiremorethanunshadedleaves,theycontribute lessto the drymatter
production.Thereis,therefore,an optimumLAIfor maximum drymatter
production which is reached when the largest number of leaves receive just
sufficient sunlight for photosynthesis to balance respiration.
Belowoptimum LAI , lightisnot being fullyinterceptedandaboveoptimum
LAI ,the leaf areaisnotbeing fullyutilizedat maximum efficiency.At higher
thanoptimum LAI , lower leaves become parasiticevenunder condition of
fulllightintensity.

35. Contd…
Optimum LAI differs with crop andtheirleaf
orientation.
Optimum LAI is between 3 to 4forcropswith
horizontally oriented leaves.
Optimum LAI is between 6 to 9 forcropswith
upright leaves.

36. Formula
LAI=Leafarea/Groundarea
Unit: unitless

42. Growthanalysisparameters Definition Unit Significance
RelativeGrowthRate(RGR) Rateofincreaseindrymatter
perunitdrymatter
gg-1 day-1 Indicatestheproportionate
growth ofplantindependentof
theirsize
NetAssimilationRate(NAR) Rateofincreaseindrymatter
perunitleafarea
gcm-2 day-1 Indicatestheassimilatory
capacity ofplant
CropGrowthRate(CGR) Rateofincreaseindrymatter
perunitgroundarea
gcm-2 day-1 Indicatesthedrymatter
production capacityperunitarea
andalsoindicatesnetprimary
productivity
AverageGrowthRate(AGR) Rateofincreaseindrymattergday-1 Indicatesthegrowthofplants
LeafArea Index(LAI) Ratioofleafareatothe
groundarea
- Proportionofgroundareacovered
by leaves
LeafAreaRatio(LAR) Ratioofleafareatotheplant
dryweight
cm2g-1 Indicatesleafinessofplant
LeafWeightRatio(LWR) Ratioofleafweighttothe
plantdryweight
gg-1 Partitioningtoleaforproportion
of dryweightinvolvedin
assimilation
Specific LeafArea(SLA) Ratioofleafareatoleafweightcm2g-1 HigherSLAindicateslessthickand
orlessdensityofleaf
SpecificLeafWeight(SLW) Ratioofleafweighttothe leaf
area
g cm-2 HigherSLWindicatesmoreleaf
thicknessandordensitya
Leaf AreaDuration(LAD) Productofleafareaandthe
timeperiodwhichleafareais
maintained
cm2 day Durationofgreennessofcrop
BiomassDuration(BMD) Productofbiomassandthe
timeperiodinwhichbiomass is
maintained
gday Indicatesthebiomasspersistence
andusefulforcalculationof
maintenancerespirationover
times

43. IMAGESOFDEVELOPMENTALSTAGES
GERMINATION ANDSEEDLING VEGETATIVESTAGE
FLOWERING STAGE MATURITY STAGE