VII Simposio Internacional de Trigo

1. Global Vision on Zinc
Ismail Cakmak
Sabanci University, Istanbul

2. Zn Deficiency:
a global nutritional problem in
cultivated soils (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

3. Zn Deficiency:
Global Micronutrient Deficiency in Soils
Widespread
Medium
Alloway, 2007. IZA Publications, Brussels

4. Nearly half of the cereal cultivated soils globally
contain low amount of plant available Zn
(Graham and Welch, 1996)

5. Soil factors affecting availability of Zn to roots
 high CaCO3
 high pH
SOIL  clay soils
 low organic matter
Zn  low soil moisture
 high Fe and Al oxides
Zn
Zn Enhanced Zn adsorption Zn
Zn and precipitation
Zn
Limited Zn
Zn uptake Decreased Zn desorption
Zn
Zn

6. Additional Cause of Zn Deficiency:
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

7. Why Plants Need Zinc

8. Basic Roles of Zinc in
Biological 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 pollination
Marschner, 1995; Cakmak, 2000, New Phytol.

9. Basic Roles of Zinc in
Biological 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 pollination
Marschner, 1995; Cakmak, 2000, New Phytol.

10. Zinc Deficiency-Induced
Root Exudation
Pathogenic Pathogenic
Attack Amino acids, Attack
Sugars..

11. Basic Roles of Zinc in
Biological 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 pollination
Marschner, 1995; Cakmak, 2000, New Phytol.

12. ZINC PROVIDES DEFENSE AGAINST FREE RADICAL DAMAGE IN CELLS
ZINC IS NEEDED FOR O2 ZINC IS NEEDED FOR
DETOXIFICATION h.v. e -
INHIBITION OF
OF FREE RADICALS ._
RADICAL GENERATION
O2
1
O2
.
H2O2 OH
MEMBRANE DNA CHLOROPHYLL PROTEIN
S-H
S -H
S=S
S=S
LIPID MUTATION CHLOROSIS PROTEIN
PEROXIDATION DAMAGE
CELL DEATH

13. Zn Deficiency Makes Plants Highly
Sensitive to High Light and Heat
Cakmak, 2000; New Phytologist, 146: 185-205

14. Partial shading of primary leaves
of Zn-deficient bean plants

15. Basic Roles of Zinc in
Biological 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 pollination
Marschner, 1995; Cakmak, 2000, New Phytol.

16. 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
less IAA synthesis
Zn
deficiency
higher oxidative IAA
degradation

17. Unde Zn deficiency IAA is Reduced
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 Shoot
Zn Free amino acids IAA
M dry wt.
g/plant mg kg-1 µmol g-1 dry wt. µg kg-1 fresh wt.
+Zn (10-6) 8.24 52 82 240
- Zn 3.66 13 533 122
Zn-Resupply 4.53 141 118 180
Cakmak et al., 1989, J. Experimental Botany, 40:405

18. Reduced Shoot
Elongation and +Zn
Little Leaf
Formation are very
Characteristic for
-Zn
Zn deficiency
‘little
leaf’
Apple,
N-China

19. Basic Roles of Zinc in
Biological 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 pollination
Marschner, 1995; Cakmak, 2000, New Phytol.

20. Specific high Zn demand for pollination
Effect of Zn supply on growth, grain yield, viability
and Zn concentration of pollen in maize plants
Zn supply Shoot Dry Grain yield Pollen Zn conc. in
Weight (g/plant) viability pollen (mg/
(g/plant) (%) kg)
Adequate 74 70 85 75
Zinc
Zinc 67 18 20 27
Deficiency
Sharma et al., Plant Soil 124, 221-226; 1990

21. Zinc Deficiency
Symptoms in
Wheat

22. Zn-adequate
wheat leaf

23. Development of Zn
deficieny in wheat

24. Development of Zn
deficieny in wheat

25. Development of Zn
deficieny in wheat

26. Zn deficieny in
wheat

27. Zn deficieny in
wheat

28. Severe Zn
deficieny in wheat

29. Video:
Growth of Maize and Wheat
Plants on a Zn-Deficient Soil

30. Human Zinc Deficiency

31. Micronutrient Deficiencies:
Global Malnutrition Problem
Iron Zinc
Estimated 2 Estimated
billion www.harvestplus.org 2 billion

32. Zinc affects a
range of
functions:
• Immunity
• Growth
• Brain development
• Reproduction
•….
www.harvestplus.org

33. Human Zinc Deficiency
High
Moderate
Low
Not sufficient data available
http://www.izincg.org/
Soil and Human Zn Deficiency: geographical overlap
Soil Zinc Deficiency
Widespread Zn Deficiency
Medium Zn Deficiency
Alloway, 2004. IZA Publications, Brussels

34. 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

35. ZINC SAVES KIDS
Intl’ Zinc Assoc.
IZA in partnership with UNICEF started a
program called ‘Zinc Saves Kids’
www.ZincSavesKids.org

36. Major Reason: Low 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.

37. Solutions to Micronutrient Deficiencies
• Supplementation
• Food Fortification
(not affordable in rural regions)
Golden Wheat Fortfied with Zn

38. Agricultural Solutions
(Breeding and Fertilizer Approaches)
•Breeding
•Agronomy/Fertilizers

39. HarvestPlus-
Biofortification Challenge
Program www.harvestplus.org
Breeding new cereal cultivars with
high micronutrient content in cereal grains
Coordinating Institutions:
International Food Policy Research Institute (IFPRI)
Washington DC and CIAT-Colombia
Main Sponsors: Gates Foundation and
World Bank

40. Main Sponsor of HarvestPlus Program
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.”

41. Rapid and Sustainable Solution
Application of Zinc Fertilizers:
(Agronomic Biofortification)
Application of Zn-containing fertilizers
offers a rapid solution to the problem

42. Global Zinc Fertilizer Project
II. Phase
2011 June- 2014 May

43. Rice Trials in Thailand

44. Maize Trials in Zambia

46. Wheat Trials in India

47. Maize Trials in Zimbabwe

48. WheatTrials in Pakistan

49. Maize Trials in Mozambique

50. Wheat trials in China, Yanglin-Xian

51. Thank you...

52. Staining/Localization of Zinc in
Wheat Grain (red color)
EMBRYO
ALEURONE
ENDOSPERM
ALEURONE
Cakmak et al., 2010
Cereal Chemistry, 77: 10-20

53. LA-ICP-MS Tests on Seeds
White arrow: Zn in 1000
900
Zn concentration (mg/kg)
entire cross section 800
700 entire cross section
Black arrow: Zn in 600
500
endosperm section 400
300
200
100
0
0 500 1000 1500 2000 2500 3000 3500 4000
Distance (µm)
12.0
Zn concentration (mg/kg)
10.0
8.0
6.0
4.0
endosperm section
2.0
Cakmak et al., 2010, 0.0
0 500 1000 1500 2000
J. Agric. Food. Chem. Distance (µm)

54. B
LA-ICP-MS Tests No Foliar Zn Application
25
2000
Zn concentration (mg/kg)
1800
Zn concentration (mg/kg)
20
Endosperm
1600
1400
15
1200
1000
cr
10
800
600
5
400
200
0
0
0 500 1000 1500 2000
0 500 1000 1500 2000 2500 3000 3500 4000
Distance (µm)
Distance (µm)
Foliar Zn Application at Stem Elongation and Booting Stages
2000 25
Zn concentration (mg/Kg) 1800
Endosperm
Zn concentration (mg/Kg)
1600 20
1400
1200 15
1000
800
cr
10
600
400 5
200
0 0
0 500 1000 1500 2000 2500 3000 3500 0 200 400 600 800 1000 1200 1400
Distance (µm) Distance (µm)
Foliar Zn Application at Milk and Dough Stages
2000 25
Endosperm
Zn concentration (mg/kg)
1800
Zn concentration (mg/kg)
1600 20
1400
1200 15
1000
cr
800 10
600
400 5
200
0 0
0 500 1000 1500 2000 2500 3000 3500 0 200 400 600 800 1000 1200 1400 1600
Distance (µm) Distance (µm)
Cakmak et al., 2010, J. Agric. Food. Chem. 58:9092-9102