Download - Global Vision on Zinc
Global Vision on ZincGlobal Vision on Zinc
Ismail Cakmak
Sabanci University, Istanbul
Zn Deficiency: Zn Deficiency: a global nutritional problem in a global nutritional problem in
cultivated soilscultivated soils ((30 % of soils affected)30 % of soils affected)
Australia : >10 mio ha
Turkey : 14 mio ha
Bangladesh : 2 mio ha
China : 30 mio ha
India : 90 mio ha
White and Zasoski, 1999; Field Crops Res., 60:11-26
ZZnn Deficiency: Deficiency: Global Global Micronutrient Deficiency in SoilsMicronutrient Deficiency in Soils
Alloway, 2007. IZA Publications, Brussels
Widespread
Medium
Nearly half of the cereal cultivated soils globally contain low amount of plant available Zn
(Graham and Welch, 1996)
Zn
Zn
Zn
ZnZn
high CaCO3high pHclay soilslow organic matterlow soil moisturehigh Fe and Al oxides
Decreased Zn desorption
Zn
Zn
Zn
ZnEnhanced Zn adsorption
and precipitation
SOIL
Soil factors affecting availability of Zn to roots
LimitedZn uptake
Additional Cause of Zn Deficiency: Intensification of Farming Intensification of Farming
Zinc Depletion in Soil and Zinc Dilution in the Harvested Products
Increasing grain yield potential of new varieties results in rapid depletion of
soil-Zn and dilution of seed-Zn
Why Plants Need Zinc
Basic Roles of Basic Roles of ZincZinc in in Biological SystemsBiological Systems
nearly 10 % of proteins needs Zn for their function nearly 10 % of proteins needs Zn for their function and structureand structure
structural and functional integrity of biological membranes depends on adequate amount of Zn Zinc is a major actor of cellular defense systems against highly toxic oxygen free radicals ( better tolerance to environmental stress factors, e.g., drought stress) Zinc is required for protection of IAA from oxidation Zinc is required for better pollination
Marschner, 1995; Cakmak, 2000, New Phytol.
Basic Roles of Basic Roles of ZincZinc in in Biological SystemsBiological Systems
nearly 10 % of proteins needs Zn for their function and structure
structural and functional integrity of biological structural and functional integrity of biological membranes depends on adequate amount of Zn membranes depends on adequate amount of Zn Zinc is a major actor of cellular defense systems against highly toxic oxygen free radicals ( better tolerance to environmental stress factors, e.g., drought stress) Zinc is required for protection of IAA from oxidation Zinc is required for better pollination
Marschner, 1995; Cakmak, 2000, New Phytol.
Amino acids, Sugars..
Zinc Deficiency-Induced Root Exudation
Pathogenic Attack
Pathogenic Attack
Basic Roles of Basic Roles of ZincZinc in in Biological SystemsBiological Systems
nearly 10 % of proteins needs Zn for their function and structure
structural and functional integrity of biological membranes depends on adequate amount of Zn ZZinc is a major actor of cellular defense systems against inc is a major actor of cellular defense systems against highly toxic oxygen free radicals ( better tolerance to highly toxic oxygen free radicals ( better tolerance to environmental stress factors, e.g., drought stress)environmental stress factors, e.g., drought stress)Zinc is required for protection of IAA from oxidation Zinc is required for better pollination
Marschner, 1995; Cakmak, 2000, New Phytol.
S-HS-H
MEMBRANE DNA PROTEIN
ZINC PROVIDES DEFENSE AGAINST FREE RADICAL DAMAGE IN CELLS
O2h.v. e-
LIPIDPEROXIDATION
PROTEINDAMAGE
MUTATION
CHLOROPHYLL
CHLOROSIS
S=S
1O2 O2
._
H2O2 OH.
S=S
CELL DEATH
ZINC IS NEEDED FOR DETOXIFICATION
OF FREE RADICALS
ZINC IS NEEDED FOR INHIBITION OF
RADICAL GENERATION
Cakmak, 2000; New Phytologist, 146: 185-205
Zn Deficiency Makes Plants Highly Sensitive to High Light and Heat
Partial shading of primary leaves of Zn-deficient bean
plants
Basic Roles of Basic Roles of ZincZinc in in Biological SystemsBiological Systems
nearly 10 % of proteins needs Zn for their function and structure
structural and functional integrity of biological membranes depends on adequate amount of Zn Zinc is a major actor of cellular defense systems against highly toxic oxygen free radicals ( better tolerance to environmental stress factors, e.g., drought stress)ZZinc is required for protection of IAA from inc is required for protection of IAA from oxidationoxidation Zinc is required for better pollination
Marschner, 1995; Cakmak, 2000, New Phytol.
Zn deficiency
less IAA synthesis
higher oxidative IAA degradation
Importance of Zinc for Auxin (IAA) Hormone
Evidence is available showing that Zn is involved in both biosytnhesis of IAA and also protection of IAA from oxidative attack by free radicals
Effect of Zn supply on shoot dry weight and composition of young leaves and shoot tips of bean plants.
Concentrations in young leaves and shoot tips
Zn supply
M Shoot dry wt.
Zn
Free amino acids
IAA
+Zn (10-6)
g/plant
8.24
mg kg-1
52
µmol g-1 dry wt.
82
µg kg-1 fresh wt.
240
- Zn 3.66 13 533 122
Zn-Resupply 4.53 141 118 180
Cakmak et al., 1989, J. Experimental Botany, 40:405
Unde Zn deficiency IAA is Reduced
+Zn+Zn
-Zn-Zn
Reduced Shoot Elongation and Little Leaf Formation are very Characteristic for Zn deficiency
Apple, N-China
‘little leaf’
Basic Roles of Basic Roles of ZincZinc in in Biological SystemsBiological Systems
nearly 10 % of proteins needs Zn for their function and structure
structural and functional integrity of biological membranes depends on adequate amount of Zn Zinc is a major actor of cellular defense systems against highly toxic oxygen free radicals ( better tolerance to environmental stress factors, e.g., drought stress)Zinc is required for protection of IAA from oxidation Zinc is required for better pollinationZinc is required for better pollination
Marschner, 1995; Cakmak, 2000, New Phytol.
Zn supply Shoot Dry Weight (g/plant)
Grain yield (g/plant)
Pollen viability
(%)
Zn conc. in pollen
(mg/kg)
Adequate Zinc
74 70 85 75
Zinc Deficiency
67 18 20 27
Specific high Zn demand for pollination
Sharma et al., Plant Soil 124, 221-226; 1990
Effect of Zn supply on growth, grain yield, viability and Zn concentration of pollen in maize plants
Zinc Deficiency Zinc Deficiency Symptoms in Symptoms in
WheatWheat
Zn-adequate wheat leaf
Development of Zn deficieny in wheat
Development of Zn deficieny in wheat
Development of Zn deficieny in wheat
Zn deficieny in wheat
Zn deficieny in wheat
Severe Zn deficieny in wheat
Video: Growth of Maize and Wheat Plants on a Zn-Deficient Soil
Human Zinc DeficiencyHuman Zinc Deficiency
Zinc Estimated 2 billion
Micronutrient Deficiencies: Global Malnutrition Problem
www.harvestplus.org
Iron Estimated 2
billion
Zinc affects a Zinc affects a range ofrange of functions:functions:
• Immunity• Growth• Brain development • Reproduction•….
www.harvestplus.org
Human Zinc Human Zinc DDeficiencyeficiency
Moderate
Not sufficient data availableLow
High
http://www.izincg.org/
Widespread Zn Deficiency
Medium Zn DeficiencyAlloway, 2004. IZA Publications, Brussels
Soil Zinc DeficiencySoil Zinc Deficiency
Soil and Human Zn Deficiency: geographical overlap
Children particularly sensitive to Zn deficiency
>450,000 deaths/year children under 5 – 4.4% attributed to Zn deficiency
Black et al. 2008
The Lancet Maternal and Child Undernutrition Series
IZA in partnership with UNICEF started a program called ‘Zinc Saves Kids’www.ZincSavesKids.org
Intl’ Zinc Assoc.
ZINC SAVES KIDSZINC SAVES KIDS
Major Reason:Major Reason: Low Dietary IntakeLow Dietary Intake High Consumption Cereal Based Foods with Low Micronutrient Concentrations
In number of developing countries, cereals contributes nearly 75 % of the daily calorie intake.
Solutions to Micronutrient Deficiencies
•Supplementation Supplementation •Food FortificationFood Fortification (not affordable in rural
regions)
Golden Wheat Fortfied with Zn
Agricultural Solutions(Breeding and Fertilizer Approaches)
•Breeding
•Agronomy/Fertilizers
HarvestPlus-Biofortification Challenge Program
Breeding new cereal cultivars with new cereal cultivars with high micronutrient content in high micronutrient content in cereal cereal graingrainssCoordinating Institutions: International Food Policy Research Institute (IFPRI)Washington DC and CIAT-Colombia
Main Sponsors: Gates Foundation and World Bank
www.harvestplus.org
www.gatesfoundation.org
“Two billion people in the developing world suffer from diets lacking essential vitamins and minerals.
Foods rich in vitamins and minerals are essential for a healthy diet. When diets do not contain sufficient amounts of vitamin A, folic acid, iodine, iron, and zinc, the consequences include significantly lower birth weight, a decrease in cognitive development, and increased susceptibility to other diseases.”
Main Sponsor of HarvestPlus Program
Application of Zinc Fertilizers: Application of Zinc Fertilizers: (Agronomic Biofortification)
Rapid and Sustainable Solution
Application of Zn-containing fertilizers offers a rapid solution to the problem
2011 June- 2014 May
Global Zinc FertilizerGlobal Zinc Fertilizer ProjectProjectII. PhaseII. Phase
Rice Trials in Thailand
Maize Trials in Zambia
Wheat Trials in India
Maize Trials in Zimbabwe
WheatTrials in Pakistan
Maize Trials in Mozambique
Wheat trials in China, Yanglin-Xian
Thank you...Thank you...
Staining/Localization of Zinc in Wheat Grain (red color)
EMBRYO
ENDOSPERM
ALEURONE
ALEURONE
Cakmak et al., 2010
Cereal Chemistry, 77: 10-20
LA-ICP-MS Tests on Seeds
0100200300400500600700800900
1000
0 500 1000 1500 2000 2500 3000 3500 4000
Distance (µm)
Zn
co
nce
ntr
atio
n (
mg
/kg
)
0.0
2.0
4.0
6.0
8.0
10.0
12.0
0 500 1000 1500 2000
Distance (µm)
Zn
co
nce
ntr
atio
n (
mg
/kg
)
Cakmak et al., 2010,
J. Agric. Food. Chem.
White arrow: Zn in entire cross section
Black arrow: Zn in endosperm section
entire cross section
endosperm section
0200400600800
100012001400160018002000
0 500 1000 1500 2000 2500 3000 3500 4000
Distance (µm)
Zn
co
nce
ntr
atio
n (
mg
/kg
)
0200400600800
100012001400160018002000
0 500 1000 1500 2000 2500 3000 3500
Distance (µm)
Zn
co
nce
ntr
atio
n (
mg
/Kg
)
0200400600800
100012001400160018002000
0 500 1000 1500 2000 2500 3000 3500
Distance (µm)
Zn
co
nce
ntr
atio
n (
mg
/kg
)
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5
10
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25
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Distance (µm)
Zn
co
nce
ntr
atio
n (
mg
/kg
)
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10
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0 500 1000 1500 2000
Distance (µm)
Zn
co
nce
ntr
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n (
mg
/kg
)
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Distance (µm)
Zn
co
nce
ntr
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n (
mg
/Kg
)
No Foliar Zn Application
Foliar Zn Application at Stem Elongation and Booting Stages
Foliar Zn Application at Milk and Dough Stages
B
cr
cr
cr
Endosperm
Endosperm
Endosperm
LA-ICP-MS Tests
Cakmak et al., 2010, J. Agric. Food. Chem. 58:9092-9102