Environmental Plant Physiology
Objectives
Environmental Plant Physiology
Summary
• The objectives of this course are to learn plant responses to
abiotic stresses, particularly plant growth and development,
and to learn modeling methodologies on how to integrate
those plant processes under multiple stress conditions.
• At the end, the students are expected to:
K. Raja Reddy
Mississippi State University
Mississippi State, MS
9 understand individual as well as interactive abiotic
stress effects on photosynthesis, respiration, growth,
development and finally yield.
9 understand on how to develop methodologies to
integrate multiple stress factor effects on various
plant/canopy processes.
Trends, Signs and Signatures from the Earth
Past, Present and Future World Population
14
Trends That Shape Our Future
Population in Billions
12
World Population
10
8
6
4
2
0
0
500
1000
1500
2000
2500
Year
Trends, Signs and Signatures from the Earth
Trends, Signs and Signatures from the Earth
Present and Future World Population Trends
Global Major Foods – Per Capita Consumption
3000
56%
Vegetables = 3.21 lb/year
400
2,367
2000
1,941
1,628
1500
450
2000
2050
120%
1,520
1,437
1,301
-5%
42%
39%
1,087
1000
885
728
778
668
549
500
457
326
Consumtion, lb/person
Population, millions
2500
10% 50%
350
Selected fruits = 1.95 lb/year
300
250
Meat and Poultry = 0.65 lb/year
200
150
Flour and Cereals = 2.70 lb/year
0
Asia
China
Oceania
(less China and India)
India
Africa
North
Europe Latin
America America
100
1965
1970
1975
1980
1985
1990
1995
2000
Year
1
Trends, Signs and Signatures from the Earth
Trends, Signs and Signatures from the Earth
Global Major Foods – Meat and Poultry Production
Maize - Production and Yield – Selected Counties
12000
Meat and Poultry Production
Relative Trends
Meat and Poultry Production
10000
350
P= 67%, and A= 46%
Yield
Production
USA: 156% @ 114 kg yr-1
China: 335% @ 100 kg yr-1
USA: 226% @ 3.90 MMt yr-1
China: 631% @ 2.77 MMt yr-1
Brazil: 364% @ 0.73 MMt yr-1
Brazil: 157% @ 47 kg yr-1
300
10
150
100
50
0
1950
1960
1970
1980
1990
2000
2010
Year
250
1961 to 2007: Million t
Poultry = 9 and 87
Meat = 71 and 286
8
Poultry
7
6
5
8000
USA
USA
200
6000
150
China
4000
China 100
4
Brazil
Meat
3
2000
Brazil 50
2
1
0
1960
0
1960
1970
1980
1990
2000
1970
1980
1990
2000
2010 1960
1970
1980
1990
2000
0
2010
2010
Year
Year
Year
Trends, Signs and Signatures from the Earth
Trends, Signs and Signatures from the Earth
Rice - Production and Yield – Selected Counties
Management Practices
8000
250
Production
-1
China: 232% @ 2.98 MMt yr
-1
India: 339% @ 2.15 MMt yr
Yield
-1
-1
6000
Indonesia: 132% @ 1.12 MMt yr
150
Indonesia
India
100
3000
50
India
Indonesia
2000
0
1000
P= 60%, and A= 55%
1980
1990
2000
2010 1960
1970
Year
1980
1990
2000
Soil organic carbon (%)
China
1970
Sanborn Field: Central Missouri
3.5
China
0
1960
4
Morrow plots: East-central Illinois
200
5000
4000
Fertility management
Crop rotations
4.0
-1
3.0
2.5
2.0
1.5
1.0
2010
Year
Soil organic carbon (%)
Indonesia: 156% @ 77 kg yr
-1
India: 90% @ 42 kg yr
Rice production, MMt
7000
China: 205% @ 102 kg yr
Maize production, MMt
200
9
Maize yield, kg ha-1
Meat and Poultry production trends,1961 = 1
Poultry
Meat
250
Rice yield, kg ha-1
Corn-oats-hay rotation
Corn-oats (1885-1953), Corn-soybeans (1954-1988)
Continuous corn
Estimated
to 4% in 1888
Wagner, (1989)
3
2
1
Wheat, 6 Tons Manure/year
Corn, 6 Tons Manure/year
Continuous Wheat
Continuous Corn
0
1880
1880 1900 1920 1940 1960 1980 2000
Year
Reicosky et al. 2000
1900
1920 1940
Year
1960
Trends, Signs and Signatures from the Earth
Trends, Signs and Signatures from the Earth
Cropland area, Irrigation and Salinization
Population, cereal yield, arable and irrigated area, N use
5
Year 2000
Cropland area
Irrigated area
Salinized area
----------------------------- Mha -------------------------------China
124.0
54.4 (22%)
7-8 (14%)
India
161.8
54.8 (31%)
10-30 (50%)
USA
177.0
22.4 (13%)
4.5 -6 (15%)
USSR
204.1
19.9 (2%)
2.5-4.5 (21%)
World
1364.2
271.7 (21%)
62-82 (37%)
Percent change since 1985
Relative valuses (1961=1)
Meat and Poultry production, million t
300
4
3
1980
5
Cereal yield
Arable land area
Irrigated land area
Population
Fertilizer use
4
2000 values are:
Cereal yield = 2.25
Arable area = 1.09
Irrigated area = 1.98
Population = 1.97
Fertilizer use = 4.33
3
2
2
1
1
0
0
1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005
Year
2
Routes to Greater Food Production
Feeding 10 Billion Mouths
We must develop the capacity to feed 10 billion people
within in the next 40 to 50 years.
• The average world current cereal yield is about 3
tons per ha for about 6 billion people.
• We need about 4 tons per ha for 8 billion (33 %
more than the current), and 5 tons per ha for 10
billion (67 % more than the current).
Here comes the greatest
challenge of our time,
The Global Climate Change
•
Increase in the area of land under cultivation.
•
Increase in the number of crops per hectare per year
(mostly practiced in tropics, requires access to irrigation,
high input use, short season cultivars, and others such as
labor, pest and disease control may be a problem).
•
Displacement of lower yielding crops by higher
yielding ones (done since the dawn of domestication).
•
Efficiency of crop production in terms of:
Per unit of land area (yield per ha)
Per unit of time
Per unit of inputs such as fertilizers, water and labor etc.
Environmental Stresses and
Plant Growing Conditions
Environmental and Cultural Factors
Limiting Potential Yields
Area of Total World Land Surface Subject to
Environmental Limitations of Various Types
Limitation
¾ Atmospheric carbon dioxide
¾ Solar radiation
¾ Temperature (extremes)
¾ Water (irrigation and rainfall)
¾ Wind
¾ Nutrients (N, P, K, and other nutrients)
¾ Others, Ultra-violet radiation, ozone etc.,
¾ Growth regulators (such as PIX)
Area of world soil subject to limitation (%)
Drought
27.9
Shallow soil
24.2
Mineral excess or deficiency
22.5
Flooding
12.2
Miscellaneous
3.1
None
10.1
Total
100
Temperature
14.8 (over laps with other stresses)
3
Environmental Plant Physiology
Chapter 1
• Atmospheric carbon dioxide
Environmental Plant Physiology
Chapter 2
• Solar radiation
• Temperature (Including extremes)
Photosynthesis and the environment
• Water
• The Environmental productivity Index (EPI)
concept.
• Wind
• Nutrients
• The photosynthesis - Species variability.
• Other factors such as ozone
• Photosynthesis and aging process.
• Plant growth regulators
• Respiration.
• The facilities and tools
Environmental Plant Physiology
Chapter 3
Crop growth and development
•
Phenology
•
Growth of various organs and whole plants.
•
The concept of environmental productivity
index in quantifying crop growth and
development in response to the environment.
Environmental limiting crop growth,
development and yield
¾ Atmospheric Carbon Dioxide
¾ Solar Radiation
¾ Temperature
¾ Water (indirect)
¾ Wind
¾ Nutrients (N, P, K)
¾ Ozone, UV-B etc.,
¾ Growth Regulators
Environmental Plant Physiology
Chapter 4
Scaling of processes from leaves to whole
plant, canopies or ecosystems.
Chapter 5
Special topics include:
•
Remote sensing and environmental plant
physiology.
Environmental limiting crop growth,
development and yield
¾ Atmospheric Carbon Dioxide
¾ Solar Radiation
¾ Temperature
¾ Water (indirect)
¾ Wind
¾ Nutrients (N, P, K)
¾ Ozone, UV-B etc.,
¾ Growth Regulators
4
Global Carbon Dioxide Concentrations
Trends over the last two centuries
400
CO2 Concentration, ppm
375
350
325
300
275
250
1700
1750
1800
1850
1900
1950
2000
2050
Year
A Hierarchy of Plant Responses to CO2
Atmospheric CO2
?
?
Stomatal Resistance
Photosynthesis
Transpiration
Environmental limiting crop growth,
development and yield
Photorespiration
¾ Atmospheric Carbon Dioxide
¾ Solar Radiation
¾ Temperature
¾ Water (indirect)
¾ Wind
¾ Nutrients (N, P, K)
¾ Ozone, UV-B etc.,
¾ Growth Regulators
Carbon Availability
Tissue Temperature
Tissue Water Potential
Growth and Development
Yield
Radiation and Plant Life
2500
7
360 µL L-1
Solar Radiation
6
5
Maize, DAE 37
2000
4
1500
3
2
1000
1
500
0
PPFD, µmol m-2 s-1
Carbon Exchange Rate, mg CO2 m-2 s-1
Net Photosynthesis and Available Light Intensity
-1
0
-2
0
2
4
6
8
10
12
14
16
18
20
22
24
Time of the Day (Central Standard Time)
5
Leaf and canopy development and aging process
Photosynthesis and Solar Radiation
Species variability
Leaf
Am – Amaranthus
Au – Aubergine
5-day
12-day
2-day
Ba – Barley
Canopies
Emerging leaf
8-day
Emergence
Be – Bean
Squaring
Bg – Bermudagrass
Ca – Cabbage
Ch – Chrysanthimum
Co – Cotton
Flowering
Cu – Cucumber
Pe – Pepper
About to abscise
Ro – Rose
Ry – Ryegrass
Mature crop
So – Sobean
To - Tomato
Solar Radiation and Dry Matter Production
Effects of Multiple Environmental Factors on
Crop Growth and Developmental Aspects
• Introduced Environmental Productivity Index (EPI)
concept.
• Photosynthesis
• Crop Phenology or Development
• Crop Growth
• Reproductive Biology
Canopy Photosynthesis - Growing Season
Canopy Photosynthesis - Growing Season
Accounting for environmental factors using EPI concept
Accounting for environmental factors using EPI concept
200
-2
Photosynthesis, g CO2 m d
Inc oming Sola r
150
100
50
0
If the crop ca n intercept a ll the ra dia tion
-1
-1
-2
Photosynthesis, g CO2 m d
200
If the crop ca n intercept a ll the ra dia tion
Interc ep ted Sola r
-50
Inc oming Sola r
150
100
50
0
Interc ep ted Sola r
-50
0
20
40
60
80 100 120
Days after Emergence
140
160
0
20
40
60
80 100 120
Days after Emergence
140
160
6
Canopy Photosynthesis - Growing Season
Accounting for environmental factors using EPI concept
200
If the crop ca n inte rcept a ll the ra dia tion
-1
Inc oming Sola r
150
Variable
100
Amount, MJ
Total Incoming Radiation
2842
Intercepted Radiation
1551
Percent Intercepted
55
50
Incoming Solar
Intercepted Solar (Potential)
Potential * UV-B
Potential * UV-B * T
Potential * UV-B * T * LW P
Potential * UV-B * T * LW P * N
Potential * UV-B * T * LW P * N * K
0
-50
0
20
40
60
80 100 120
Days after Emergence
140
160
Photosynthesis – EPI Concept
Accounting for Individual factors
Variable
Photosynthesis – EPI Concept
Accounting for Multiple Factors
Amount, g CO2 m-2 season-1
Amount, g CO2 m-2 season-1
Variable
Incoming R
19644
Incoming R
19644
Intercepted R
11441 (100%)
Intercepted R
11441 (100%)
Int. R * UV-B
10448 (9%)
Int. R* UV-B
10230 (9%)
Int. R.* T
10139 (11%)
Int. R* UV-B*T
Actual
amount
9153 (20%)
Int. R.* W
9783 (14%)
Int. R* UV-B*T*W
7551 (34%)
Int. R.* N
8986 (21%)
Int. R*UV-B*T*W*N
6292 (55%)
Int. R*UV-B*T*W* K
4576 (60%)
Int. R * K
10841 (5%)
Environmental limiting crop growth,
development and yield
Long-Term Average Temperatures
40
35
¾ Atmospheric Carbon Dioxide
¾ Solar Radiation
¾ Temperature
¾ Water (indirect)
¾ Wind
¾ Nutrients (N, P, K)
¾ Ozone, UV-B etc.,
¾ Growth Regulators
Temperature, °C
-2
Photosynthesis, g CO2 m d
Radiation Totals for the 1992 Growing season
Mississippi State – North Farm
Phoenix, AZ
30
25
Maros, Indonesia
20
15
10
Stoneville, MS
5
0
0
50
100
150
200
250
300
350
Day of the Year
7
Temperature Conditions - Diurnal Trends
Mississippi State, MS - 1995
40
Temperature, °C
35
30
19 Aug. 1995
25
20
15
2 May, 1995
10
23 Sep. 1995
5
0
0
2
4
6
8
10 12 14 16 18 20 22 24
Hours (CST)
Environment Factors
Temperature:
¾ Strongly Affects:
-- Phenology
-- Vegetative growth, LAI, LAD
-- Fruit Growth and Retention
-- Respiration
-- Water-loss and Water-Use
¾ Moderately Affects:
-- Photosynthesis on a canopy basis
High-temperature Injury
Heat-blasted Cotton Flowers
and Squares – Arizona
Environmental limiting crop growth,
development and yield
Heat-blasted Cotton Squares
California’s San Joaquin Valley
¾ Atmospheric Carbon Dioxide
¾ Solar Radiation
¾ Temperature
¾ Water (indirect)
¾ Wind
¾ Nutrients (N, P, K)
¾ Ozone, UV-B etc.,
¾ Growth Regulators
8
Water
Water plays essential roles in plants as a:
¾ Constituent
¾ Solvent
¾ Reactant in various chemical processes
¾ Maintenance of turgidity
The physiological importance of water is reflected in its
ecological importance.
The distribution plants over the earth’s surface is controlled by
the availability of the water (amount and seasonal distribution of
precipitation) where ever temperature permits growth.
Role of water in cotton
Environment Factors
Sensitivity to water deficit
Leaf GR
LAI
Water Deficits:
Stem GR
Cell expansion
Vegetative
yield
height
Root GR
Water
deficit
Mesophyll
Resistance
Canopy
Rate of
photosynthesis
Photosynthesis
Stomatal
Resistance
Seasonal
transpiration
Rate of
Transpiration
Cell division &
differentiation
bolls
Rate of squaring
Node production
Economic
shedding yield
¾ Strongly affects:
-- Vegetative growth, LAI, LAD
-- Fruit Growth and Retention
-- Water-loss and Water-Use
-- Photosynthesis
¾ Moderately affects certain phenological events:
-- Phenology (leaf development)
Boll GR
Sequence of events
Environment – Wind and Hail
Environmental limiting crop growth,
development and yield
¾ Atmospheric Carbon Dioxide
¾ Solar Radiation
¾ Temperature
¾ Water (indirect)
¾ Wind
¾ Nutrients (N, P, K)
¾ Ozone, UV-B etc.,
¾ Growth Regulators
9
Environment - Nitrogen
Photosynthesis - Variability Among Species
Response to Leaf Nitrogen
3
Sorghum
Cotton
Sunflower
2
Rice
Soybean
1
Environmental Productivity
Idices for Nitrogen
Photosynthesis, mg CO2 m-2 s
-1
1.2
Maize
1.0
0.8
Stem Growth
Photosynthesis
0.6
Leaf Development
0.4
0.2
Leaf Growth
0
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
0.0
1.00
1.25
Leaf Nitrogen, g m-2
Environment - Nitrogen
Parameter
1.50
1.75
2.00
2.25
2.50
Leaf Nitrogen, g m-2 leaf area
Environment - Nitrogen
Percent Reduction from the Optimum (2.5 g N/m-2 or 4.5%)
Leaf N, g m-2 Photosynthesis Stem growth Leaf growth
Leaf Development
2.5
100
100
100
100
2.0
12
14
18
12
1.5
53
60
>99
68
1.2
76
--
--
--
Environment Factors
Environment - Nutrients
Potassium - Cotton Growth and Development
Environmental Productivity Indices
¾ Strongly Affects:
-- Leaf growth, LAI, LAD
-- Fruit Retention
¾ Moderately Affects:
-- Photosynthesis
-- Stem growth
1.6
Environmental Productivity Indices
for Growth and Development
Fertilizers Deficits - Potassium:
1.4
Stem Elongation
1.2
Photosynthesis
1.0
0.8
0.6
Leaf Initiation Rates
0.4
Leaf Growth
0.2
0.0
-0.2
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
Leaf Potassium, %
10
Environment Factors
Environmental limiting crop growth,
development and yield
Ultraviolet-B Radiation:
¾ Atmospheric Carbon Dioxide
¾ Solar Radiation
¾ Temperature
¾ Water (indirect)
¾ Wind
¾ Nutrients (N, P, K)
¾ Ozone, UV-B etc.,
¾ Growth Regulators
¾ Strongly Affects:
-- Photosynthesis
-- Stem growth
¾ Moderately Affects:
-- Leaf growth
-- Leaf aging
¾ No Effects:
-- Phenology
Effects of Radiation on Plant Life
Solar Radiation and Plant Life
For plants, radiation is:
Spectral
Region
Wavelength
nm
%
Photo- Effects
synthe- Photo
Photo Thermal
sis
morpho- destrugenetic ctive
Ultraviolet
290-380
0-4
IS
Slight
S
IS
PAR
380-710
21-46
S
S
Slight
S
Infrared
750-4000
50-79
IS
S
IS
S
Longwave
4000-100000
IS
IS
IS
S
¾ A source of energy (photoenergetic effect).
¾ Stimulus for development (photocybernetic
effect).
¾ Stress factor (photodestructive effect).
IS = Insignificant, S = Significant
Ultraviolet Radiation
Why are we concerned with UV now?
•
UVC: <280), UVB: 280-320, and UVA: 320-400.
•
UVA is not absorbed by ozone.
•
UVB is mostly absorbed by ozone, although some reaches
the Earth.
•
UVC is completely absorbed by ozone and normal oxygen.
11
Satellite Based Ozone levels - 2001
USDA – UV Radiation Monitoring
Program
Satellite Based UV Radiation levels - 2001
UV-B Radiation – Growth
EPI Factors for various growth Processes
7
30
First fruit position
6
25
Emergence to squaring
4
20
3
2
Duration (d)
First fruit position on mainstem
Squaring to flowering
5
15
1
0
10
-4
0
4
8
12
16
20
UV-B treatment (kJ m-2 d-1)
UV-B Radiation – Phenology
UV-B Radiation – Cotton Growth
EPI Factors for various Developmental Processes
EPI Factors for various growth Processes
1.2
1.0
1.0
0.8
0.8
UV-B index
UV-B index
1.2
Node addition
2
2
y = -0.0003x + 0.0014x + 0.9997 R = 0.4619
0.6
0.6
Leaf are a e xpansion
2
2
0.4
y = -0.0015x + 0.0102x + 0.9914 R = 0.8136
0.4
0.2
Ste m e longation
2
2
y = -0.0023x + 0.0105x + 0.9926 R = 0.9331
0.2
Leaves retained = -0.0013x 2 + 0.008x + 1
Bolls retained = -0.0015x 2 + 0.0026x + 1
Total Boll No. = -0.0023x 2 - 0.0086x + 1
Canopy Phs = -0.0018x 2 - 0.0043x + 0.9802 R2 = 0.9139
Total DW = -0.0024x 2 + 0.0021x + 0.9856 R2 = 0.9146
0.0
0.0
-4
0
4
8
12
UV-B treatments (kJ m-2 d-1)
16
20
-4
0
4
8
12
-2
UV-B treatments (kJ m
16
20
-1
d )
12
Environmental limiting crop growth,
development and yield
Environment Factors
Growth Regulators - Mepiquat Chloride
(PIX):
¾ Atmospheric Carbon Dioxide
¾ Solar Radiation
¾ Temperature
¾ Water (indirect)
¾ Wind
¾ Nutrients (N, P, K)
¾ Ozone, UV-B etc.,
¾ Growth Regulators
¾ Moderately Affects:
-- Leaf, stem and branch growth and LAI
¾ Slightly Affects:
-- Photosynthesis
Mepiquat Chloride (PIX) - Growth
EPI Factors
1.2
Environmental Plant Physiology
and Remote Sensing
PIX and EPI Indices
1.0
Leaf growth
0.8
Photosynthesis
0.6
0.4
Stem growth
0.2
0.0
0.00
0.01
0.02
0.03
• Special topics
¾ Remote sensing
9 Introduction to remote sensing
9 Interrelationships between stress
physiology, crop growth condition and
remote sensing signatures.
Mepiquat Chloride, mg g-1 dry weight
Flow Diagram of GOSSYM
Cotton Crop Simulation Model
Technology Fusion and Delivery System
GOSSYM
DATES
CLYMAT
TMPSOL
SOIL
FERT
RAIN
PIX
FRTLIZ
RUNOFF
Crop Models
GIS
GRAFLO
ET
CHEM
PREP
UPTAKE
CAPFLO
PNET
NITRIF
GROWTH
ABSCISE
PLTMAP
PMAP
COTPLT
FREQ
RUTGRO
NITRO
RIMPED
Related database
MATAL
OUTPUT
13
Environmental Plant Physiology
and Crop Modeling
• Modeling forces the organization of known
information and concepts.
• Although we may not know enough to develop a
comprehensive model that includes all aspects of the
farm or crop production system, modeling some
meaningful portions of the system provides clarity.
• For a model to correctly predict plant responses to
physical conditions, the concepts and the response
functions must be appropriately assembled.
Environmental Plant Physiology
Summary and Conclusions
• To study the effects of environmental factors on growth,
development and other processes, we need:
9 Controlled environmental facilities with realistic
environmental conditions including solar radiation.
9 Breakdown whole systems into sub-systems and study
the influence of environmental factors on those
subsystems.
9 Develop some concepts such as EPI to quantify the
effects of multiple environmental factors on subsystems.
9 Integrate sub-systems into coherent whole
plant/field/ecosystem system-level models/tools.
Environmental Plant Physiology, Crop Modeling, and
Technology Integration for Decision Support System
• Critical environment-genotype relations should be
incorporated into the model.
• When a crop model is based on appropriate concepts
and processes it will have the predictive capability in
new environments, and can be used either alone or with
other emerging newer technologies to disseminate
useful production information.
• Also, crop models should be integrated with other
related technologies for technology integration and
delivery.
Environmental Plant Physiology
Summary and Conclusions
• Validated/integrated system simulation models will be
useful:
9 To test hypothesis.
9 To understand multiple environmental effects or
interactions.
9 For resources management at the filed-level.
9 For resource management to assist policy decisions.
9 As an educational tool to understand the effects of
environment/management effects on crop functioning.
9 For impact assessment of climate change on cop
production systems across regions and nations.
“You cannot build peace on
empty stomachs.”
John Boyd Orr
Nobel Peace Laureate
First FAO Director General
“You can’t eat the potential yield,
but need to raise the actual by
combating the stresses”
Norman E. Borlaug
Nobel Peace Laureate
14