A brief description of the role of zinc in plant nutrition

1. Debanjan Paul

2. Zinc is one of the most important micronutrient for plant growth
Molecular weight : 65
Atomic number : 30
Major form of uptake is Zn
++
The range of Zinc concentration for Maximum plants between 25 –
100 ppm.
Zinc is partially mobile in plants.

3. ROLE OF ZINC IN PLANT SYSTEM
ENZYME COFACTOR: Zn is constituent of many enzymes like carbonic
anhydrase, aldolase, ribonuclease etc.
PROTEIN METABOLISM : Zn is necessary for activity of RNA
polymerase enzyme and it protects ribosomal RNA from ribonuclease
enzyme.
AUXIN METABOLISM : Zn is required in synthesis of tryptophan, the
precursor auxin. Lack of Zn reduces the level of auxins in plants.

4. MEMBRANE INTEGRITY : The role of Zn in maintaining the integrity
of cellular membrane involving structural orientation of structural
orientation of macromolecules and maintenance of ion transport system.
UPTAKE AND STRESS: Zinc seems to effect the capacity for water
uptake and transport in plants and also reduce the adverse effects of short
periods of heat and salt stress.

5. Nitrogen(N): Nitrogen increases Zn uptake by roots as well as its
translocation to the shoot.
Phosphorous(P): Application of high levels of P inhibits
translocation of Zn from roots to metabolic sites in leaves.
C INTERACTION WITH OTHER NUTRIENTS:

6. Potassium(K) : Zn has a definite role in maintaining membrane
integrity in plants and Zn deficiency increased exudation of K
+
, amino
acids and phenolic in cotton (Gossypium hirsutum), wheat (Triticum
aestivum ).
Calcium(Ca): Calcium plays an important role in cell permeability
and stabilization of plasma membrane by Ca under Zn toxicity conditions.
Magnesium(Mg): Mg increased Zn concentration.

7. Sulphur(S): There is both positive and negative interaction.
Application of S lowered Zn concentration in groundnut (Arachis hypogaea
) shoots and depressed dry matter yield.
Boron(B): Zn application has been recommended for alleviating B
toxicity on B rich soils.
Iron(Fe), Manganese(Mn) and Copper(Cu): Application of
Zn reduced Fe content but increased Mn and Cu concentration in corn
plants, Iron application is also reported to help in alleviating Zn toxicity.

8. Figure 1:
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eficiency+in+india&gs_l=img.3..0i24l2.2002.3393..3591

9. The Zn translocation to roots xylem occurs via symplast and apoplast but
its high levels have also been detected in the phloem, denoting that this
metal is translocated through both xylem and phloem tissue.
DISTRIBUTION OF ZINC IN PLANT ROOTS AND TOPS

10. levels Denotation Treatments Shoot+Root Root Shoot
Control T0 12.21 2.54 9.67
200ppm T1 29.21 4.66 24.80
300ppm T2 17.53 2.54 15.24
400ppm T3 13.30 2.02 10.97
Source : N. J. Malik, A. S. Chamon, M. N. Mondol, S. F. Elahi and S. M. A. Faiz
Journal of the Bangladesh Association ofYoung ResearchersVol.1(1) 2011.
TABLE NO.1 : EFFECT OF DIFFERENT LEVELS OF ZnTREATMENT ON LENGTH OF
SHOOT AND ROOT(in cm/plant) OF RED AMARANTHUS.

11. Zn levels Denotation Shoot+root Root Shoot Spikelet
Control T0 14.33 84.00 71.67 9.33
200 ppm T1 84.67 12.67 73.33 11.67
300 ppm T2 117.00 20.00 96.67 10.67
400 ppm T3 102.00 13.00 88.33 9.33
TABLE NO.2 : EFFECT OF DIFFERENT LEVELSOF ZNTREATMENTON LENGTH OF
SHOOT, ROOT AND SPIKELET(cm/plant) OF RICE.
Source : N. J. Malik, A. S. Chamon, M. N. Mondol, S. F. Elahi and S. M. A. Faiz
Journal of the Bangladesh Association ofYoung ResearchersVol.1(1) 2011.

12. TABLE NO.3 : IMPACT OF ZINC APPLICATION ONYIELD, NUTRIENT QUALITY, AND
NUTRIENT
UPTAKE OF WHEAT IN DEEP BLACK SOIL
Source : Keram, BL Sharma, SD Sawarkar (2012).International Journal of Science, Environment
andTechnology, 1:563 - 571
Note: N-Nitrogen, P-Phosphorus, K-potassium, Zn fertilizer- ZnSO4

13. Zinc fertilizer:ZnSO4
Source: J Potarzycki,W Grzebisz ,2009 Plant Soil Environment. 61: 468–474
Effect of Different doses of Zinc on Maize plant
(at 5 to 6 leaf stage)
Figure no.2:

14. Visual symptoms due to zinc deficiency: -
 Chlorosis - Yellowing of leaves; often interveinal; in some species,
young leaves are the most affected but in others both old and new
leaves are chlorotic
 Necrotic spots - Death of leaf tissue on areas of chlorosis
 Bronzing of leaves - Chlorotic areas may turn bronze coloured
 Rosetting of leaves - Zinc-deficient dicotyledons often have shortened
internodes, so leaves are clustered on the stem

15.  Stunting of plants - Small plants may occur as a result of reduced
growth or because of reduced internode elongation
 Dwarf leaves ('little leaf') - Small leaves that often show chlorosis,
necrotic spots or bronzing
 Malformed leaves - Leaves are often narrower or have wavy margins
 Interveinal chlorosis- Upper leave shows interveinal chlorosis

16. Figure No.3:

17. SOME DEFICIENCY SYMPTOMS OF ZINC IN
DIFFERENT PLANTS
Little Leaf of Cotton
Khaira disease of Rice
White bud of maize
Mottled leaf of citrus
Figure No.4 : Zn deficiency symptom in different plants

18. SOME OTHER DISEASES OF PANTS CAUSED DUE TO
DEFICIENCY OF ZINC ARE :-
Bronzing in Guava and Litchi
Little leaf in cashew nut
Rosette in peanut

19. Low Medium High
Bean
Citrus
Flax
FruitTrees(deciduous)
Grapes
Hops
Maize ( Corn)
Pecan nuts
Rice
Sorghum
Barley
Cotton
Lettuce
Potato
Soybean
Sudan Grass
Sugar Beat
Table beet
Tomato
Alfalfa
Asparagrass
Carrot
Clover
Grass
Oat
Pea
Rye
Wheat
Table no. 4 : Relative sensitivity of crops to Zinc deficiency
Source : Zinc in Soils and Crop Nutrition by- Brian J. Alloway 2008,
Second edition, International Fertilizer Industry Association.

20. Figure no.5

21. Brownish spots in sweet potato
leaves
Red-Brown pigmentation
Figure No. 6 : Zn toxicity symptoms

22. SOME INDICATOR PLANTS FOR ZINC DEFICIENCY:
Rice, wheat, soybean, maize, bajra, cotton, all citruses.

23. Fertilizers Zn content in %
Zinc sulphate heptahydrate 21-23 %
Zinc sulphate monohydrate 33-36%
Zinc oxysulphate 40-55%
Zinc oxide 55-70 %
Zinc nitrate 22%
Zn-EDTA 12-14 %
Zn- HEDTA 9 %
Some Zinc containing fertilizers used in zinc deficiency soilsTable no.5 :

24.  Zinc is the most important to boost up the crop yield,
 Widespread deficiency of zinc throughout the world arising as a threat to crop
production,
 Zinc deficiency can led to several physiological disorders and ultimately decrease
in yield of major food crops like rice , wheat, maize.
 Judicious application of zinc along with suitable crop varieties can show
remarkable increase in crop yield and zinc content of crops.
CONCLUSION
S