Introduction and Crop Growth Analysis

1. CROP PHYSIOLOGY
(FISIOLOGY TANAMAN)
AGR3301

3. Introduction: CROP or PLANT PHYSIOLOGY?
• As plants grow to maturity, the cells are produced, divide, grow & become
specialized organs like:
• Stems, leaves, roots, flowers, fruits, seeds.
• CROP Physiology – The study of how these organs function and the
complex chemical processes that permit the crop to live, grow and
reproduce.
• It is the science concerned with (i) Processes and (ii) Functions, the
responses of crops to environment and the growth and development that
results from the re
• The overall goal of Crop Physiology is to evolve a detailed and
comprehensive knowledge of all the natural phenomena that occur in
living plants and thus to understand the nature of plant growth,
development and productivity. Many aspects of practical agriculture can
benefit from more intensive research in plant physiology.
Plants are multicellular photosynthetic eukaryotic life-forms belonging to
kingdom Plantae. Crops are plants grown in large quantities for food or other
commercial purposes (involve profits and subsistence). All crops are plants,
but not all plants are crops

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 :
Function means natural activity of a cell or
tissue, or organ or a chemical substance.
So, the second task of plant physiology is to
describe and explain the function of an
organ, tissue, cell and cell organelle in plants
and the function of each chemical
constituent, whether it may be an ion,
molecule or a macro molecule.
Both processes and functions are dependent
on the external factors and are modified by
the external factors such as light and
temperature.
Finally, since these two factors are modified
by the external factors, the third task of crop
physiology is to describe and explain how
processes and functions respond to change
in the environment.

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
Growth is the irreversible change in size of cells and plant organs due to
both cell division and enlargement.
Growth can be determinate—when an organ or part or whole organism
reaches a certain size and then stops growing—or indeterminate—when cells
continue to divide indefinitely.

9. Development
Development is the progression from earlier to later stages in maturation,
e.g. a fertilized egg develops into a mature tree.
It is the process whereby tissues, organs, and whole plants are produced. It
involves: growth, morphogenesis (the acquisition of form and structure),
and differentiation (identity specialisation).
The interactions of the environment and the genetic instructions inherited
by the cells determine how crop develops.

10. Differentiation
Differentiation is the process in
which generalized cells specialize
into the morphologically and
physiologically different cells.
Since all of the cells produced by
division in the meristems have
the same genetic make up,
differentiation is a function of
which particular genes are either
expressed or repressed.
The kind of cell that ultimately
develops also is a result of its
location: Root cells don't form in
developing flowers, for example,
nor do petals form on roots.

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
leaves increases,
produces flowers
tiny
and
and
seedling grows in size, the number of
later
, it grows into a mature plant and
fruits. This is the process of Growth
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 advancement towards
maturity
.
Growth is attained mainly by net
photosynthesis (after respiration loss has
been accounted for).

16. STAGES OF CELLULAR GROWTH
Growth is not a simple process. It occurs in
meristematic regions where before completion of this
process, a meristematic cell must pass through the
following 3 phases.
They are :
(i) Cell division (Formation Phase): The number of
cells increases due to mitosis.
(ii) Cell enlargement (Elongation Phase): The size of
individual cell increases after cell
division due to increase in the volume of its
protoplasm
(iii) Cell differentiation (Maturation Phase): In this
stage, structure of the cells changes to perform
specific functions. And similar type of cells having
same
functions form a group , which is known as tissue.

18. Growth curve (Sigmoid Curve) :
Typical growth pattern of an annual plant is divided into three phases.
1. Lag period of growth: during this period the growth rate is quite slow because it is
the initial stage of growth.
2. Log period of 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
how to measure growth in plants. Growth in plants being a
quantitative phenomenon can be measured in relation to
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 leaves and fruits.

20. MEASUREMENT OF GROWTH
A. Fresh weight:
Determination of fresh weight is an easy and convenient method of measuring growth. For
measuring fresh weight, the entire plant is harvested, cleaned for dirt particles if any and
then weighed.
B. Dry weight:
The dry weight of the plant organs is usually obtained by drying the materials for 21 to
48 h at 70 to 80°c and then weighing it. The measurements of dry weight may give a
more valid and meaningful estimation of growth than fresh weight.
However, in measuring the growth of dark grown seedling it is desirable to take fresh
weight.
C. Length:
Measurement of length is a suitable indication of growth for those organs which grow in
one direction with almost uniform diameter such as roots and shoots.
The length can be measured by a scale. The advantage of measuring length is that it can be
done on the same organ over a period of time without destroying it.
D. Area: it is used for measuring growth of plant organs like leaf. The area can be
measured by a graph paper or by a suitable mechanical device. Nowadays modern
laboratories use a photoelectric device (digital leaf area meter) which reads leaf area
directly as the individual leaves is fed into it.

21. GROWTH ANALYSIS
 Growth analysis is a mathematical expression of
environmental effects on growth and development of crop
plants.
 This is a useful tool in studying the complex interactions
between the plant growth and the environment.
 This analysis depends mainly on primary values (Dry weights)
and they can be easily obtained without great demand on
modern laboratory equipment.

22. Objective of Growth Analysis
1. To identify spatial and temporal integration of all plant process.
2. To know the rate of dry matter accumulation varies across the life cycle of the
crop.
3. To quantify the effects of environmental influence or to analyse the genotypic
differences between crop cultivars.
Drawbacks of growth analysis
In classical growth analysis sampling for primary values consist of harvesting
(destructively) representative sets of plants or plots and it is impossible to follow the same
plants or plots through out whole experiment.

23. COMMON PARAMETERS USED
GROWTH ANALYSIS
IN
1. ABSOLUTE GROWTH RATE(AGR)
2. CROP GROWTH RATE(CGR)
3. RELATIVE GROWTH RATE(RGR)
4. NETASSIMILATION RATE(NAR)
5. LEAF AREA INDEX(LAI)

24. ABSOLUTE GROWTH RATE (AGR)
1st
This concept was given by West et all. in 1925.
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(dry matter)/day
Absolute Growth Rate (AGR) Rate of increase in dry matter g day-1 Indicates the growth of plants

26. CROP GROWTH RATE (CGR)
1st
This concept was described by D.J. Watson in 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.
It is defined as the increase of dry matter in
grams per unit area per unit time.

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)
Coined by Blackman in 1919.
Defined as the rate of increase in dry matter per unit of dry matter
already present. This is also referred as ‘efficiency index’ since the rate
of growth is expressed as the rate of interest on the capital. .
The increase can be plotted as a logarithmic or exponential curve in
many cases.
RGR is the slope of a curve that represents logarithmic growth over a
period of time.
An exponential growth rate is not sustainable over time. The curve
typically flattens out, representing saturation in a growth at a certain
point of time .
Relative Growth Rate (RGR) Rate of increase in dry matter
per unit dry matter
g g-1 day-1 Indicates the proportionate
growth of plant independent of
their size

29. Formula:
RGR= (lnW2 –ln W1 )/(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
Rate of increase in dry matter
per unit dry matter
g g-1 day-1 Indicates the proportionate
growth of plant independent of
their size

31. NET ASSIMILATION RATE (NAR)
The concept was 1st given by Gregory (1918).
Net Assimilation Rate (NAR) Rate of increase in dry matter
per unit leaf area
g cm-2 day-1 Indicates the assimilatory
capacity of plant
The NAR is a measure of the amount of photosynthetic product going into
plant material i.e. it is the estimate of net photosynthetic carbon assimilated by
photosynthesis minus the carbon lost by respiration.
The NAR can be determined by measuring plant dry weight and leaf area
periodically during growth and is commonly reported as grams of dry weight
increase per square centimeter of leaf surface per week.
This is also called as unit leaf rate because the assimilatory area includes only
the active leaf area in measuring the rate of dry matter production.

32. Formula:
NAR= (W2-W1)(log
Where
L2 – log L1)/(t2 –t1) (L2 –L1)
W1
W2
t 1
t 2
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 matter production)/ m2/day

33. Leaf Area Index(LAI)
The concept was 1st given by Watson (1947)
Leaf area is important for photosynthesis . Its estimation 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.
Leaf Area Index (LAI) Ratio of leaf area to the
ground area
- Proportion of ground area covered
by leaves

34. Optimum LAI
LAI increases slowly in early stage of crop growth and rapidly after seedling
stage.
As LAI increases, light interception is more resulting in dry matter production.
However, at high LAI mutual shading of leaves occur and as shaded leaves
respire more than unshaded leaves, they contribute less to the dry matter
production. There is, therefore, an optimum LAI for maximum dry matter
production which is reached when the largest number of leaves receive just
sufficient sunlight for photosynthesis to balance respiration.
Below optimum LAI , light is not being fully intercepted and above optimum
LAI , the leaf area is not being fully utilized at maximum efficiency
. At higher
than optimum LAI , lower leaves become parasitic even under condition of
full light intensity
.

35. Contd…
 Optimum LAI differs with crop and their leaf
orientation.
 Optimum LAI is between 3 to 4 for crops with
horizontally oriented leaves.
 Optimum LAI is between 6 to 9 for crops with
upright leaves.

36. Formula
LAI=Leaf area/Ground area
Unit: unitless

42. Growth analysis parameters Definition Unit Significance
Relative Growth Rate (RGR) Rate of increase in dry matter
per unit dry matter
g g-1 day-1 Indicates the proportionate
growth of plant independent of
their size
Net Assimilation Rate (NAR) Rate of increase in dry matter
per unit leaf area
g cm-2 day-1 Indicates the assimilatory
capacity of plant
Crop Growth Rate (CGR) Rate of increase in dry matter
per unit ground area
g cm-2 day-1 Indicates the dry matter
production capacity per unit area
and also indicates net primary
productivity
Average Growth Rate (AGR) Rate of increase in dry matter g day-1 Indicates the growth of plants
Leaf Area Index (LAI) Ratio of leaf area to the
ground area
- Proportion of ground area covered
by leaves
Leaf Area Ratio (LAR) Ratio of leaf area to the plant
dry weight
cm2 g-1 Indicates leafiness of plant
Leaf Weight Ratio (LWR) Ratio of leaf weight to the
plant dry weight
g g-1 Partitioning to leaf or proportion
of dry weight involved in
assimilation
Specific Leaf Area (SLA) Ratio of leaf area to leaf weight cm2 g-1 Higher SLA indicates less thick and
or less density of leaf
Specific Leaf Weight (SLW) Ratio of leaf weight to the leaf
area
g cm-2 Higher SLW indicates more leaf
thickness and or densitya
Leaf Area Duration (LAD) Product of leaf area and the
time period which leaf area is
maintained
cm2 day Duration of greenness of crop
Biomass Duration (BMD) Product of biomass and the
time period in which biomass is
maintained
g day Indicates the biomass persistence
and useful for calculation of
maintenance respiration over
times

43. IMAGES OF DEVELOPMENTAL STAGES
GERMINATION AND SEEDLING VEGETATIVE STAGE
FLOWERING STAGE MATURITY STAGE