1) Silicon plays an important role in alleviating biotic and abiotic stresses in plants. It provides strength to cell walls and improves growth, health, and productivity. 2) Silicon is taken up by plants through monosilicic acid and polysilicic acid in the soil. It accumulates in leaves and other organs. Gene research has identified silicon transporters that allow for uptake in rice. 3) Applying silicon enhances plant resistance to diseases and pests. It acts as a physical barrier on plant surfaces and boosts the plant's defenses. Silicon application increases crop yields and quality.

1. Role of Silicon in Alleviating Biotic and
Abiotic Stresses in Plants
1
Speaker : Rakesh Sharma
ID. 48030 M.Sc. Ag
Deptt. of Plant Physiology
GBPUAT,PANTNAGAR

2. INTRODUCTION
 Available form: Silica dioxide
 At room temperature silicon exist in two forms
 Crystalline
 Amorphous

3. Figure: Mono & polysilicilic acids

4. Chemically active and available form of Si in soil are
•Monosilicic acid Si(OH)4
•Polysilicic acid
 Concentration range between 0.1mM - 0.6mM
(Epstein, 1994)
SILICON IN SOIL

5. ABUNDANCE IN SOIL
3/13/2016 5
Fig .Distribution of element in earth crust
Sommer et al 2006

6. Concentration of Si in plants on the basis of dry weight
varies between 0.1 - 10%.
High concentration in monocot
Its level increased from –
•legumes<fruits<vegetables< grasses<grain crops
Concentration of silicon in a plant varies from organ to
organ and accumulate higher in mature leaves

7. SILICON CYCLE
Fig: The paddy soil system silicon cycle. Meharg et al,2015

8. Fig.Fate of silicon fertilizers in soil systems Meharg et al ,2015

9. SILICON UPTAKE
Active
 Wheat
 Ryegrass
 Barley
 Rice
 Cucumber
 Melon
 Strawberry
 Soyabean
 Oats
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Plant species which exclude silicon from uptake are tomato and
bean
Passive
Zhang et al ,2015

10. SILICON UPTAKE IN RICE
10
Fig. (a)silicon uptake via transporters in rice in the form b) transported in shoot
c)&d) bulliform cells Ma et al., 2006

11. Schematic presentation of Si transport
system in rice roots
Ma et al.,2008
Fig : The schematic representation of Si transport in rice

12. Gene controlling silicon uptake in rice
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Ma et al.,2006
Fig; Different silicon transporter isolate from plants

14. Criteria:
 The element is part of a molecule which is an intrinsic
component of the structure or metabolism of the plant
The plant can be so severely deficient in the element that it
exhibits abnormalities in growth, development or
reproduction, i.e. ‘performance’, compared to plants with
lower deficiency
14
Epstein, 2005

15. Fig 10. Beneficial effect of silicon in rice grown in the field. Ma et al., 2008

16. AS
BENEFICIAL
ELEMENT
Provide strength and rigidity to cell wall, improved growth, health
and productivity
Developed potency to improved drought, frost and salt stress
 Decreased lodging.
 Developed potential and boosting the plant's against natural
insects, pests and disease causing pathogens

17. Silicon enhance potato skin quality

18. It act as physical barrier and enhance plant
resistance to toxic elements
Reduce oxidative stress and it help in alleviating
the salt damage
Alleviate drought stress (rice) by improving
plant water status, photosynthesis and mineral
nutrient absorption
It improves the yield and quality of some crops
It help in decreasing the susceptibility to disease
and insect damage.
Zhang et al,2015

19. Silicon: Enhancing yield and grain quality of plants
Meharg et al,2015

20. Biotic stress: Deposition of Si in epidermis cells
Fig . The schematic representation of rice epidermal cell.
20
Mahbod et al , 2015

21. ROLE OF SILICA DEPOSITION IN BAMBOO LEAF
DURING FUNGAL ATTACK
Fig : Silica deposition in bamboo leaf during fungal attack

22. Effect of Silicon Solubilizers on Silica
Transportation, Induced Pest and
Disease Resistance in Rice (Oryza
sativa L.)
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23. Plant diseases suppressed by silicon
PLANT DISEASE PATHOGEN
Barley Powdery mildew Erysiphe graminis
Rice( Oryza sativa ) Brown spot leaf Helminthosporium oryzae
Brown spot(husk
discoloration)
Bipolaris oryzae
Grain discoloration Bipolaris, Fusarium,
Epiccocum
Leaf and neck blast Magnoportha grisea
Stem rot Magnoportha salvani
Sheath blight Corticum saskii
Sugarcane Sugarcane rust Puccinia melanocephala
Wheat Powdery mildew Septoria nodorum
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24. Plant insects and pests suppressed by silicon
PLANT PEST INSECT
Rice Stem borer Scirpophaga interculus
Stem maggot Chlorops oryzae
Leaf spider Tetranychus
Sugarcane Stalk borer Eldana saccharia
Maize borer Sesamia calamistis
Wheat Red flour beetle Tribotium castaneum
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25. Rice blast

26. Neck blast disease of rice
A B
Fig:A ,showing rice grown without si
treatment infected by neck blast disease
Fig:,B showing plant resistance to neck blast
with treatment of silicon
Lawrence E. Datnoff et al, 2005

27. Grain discolouration in rice
Fig.A, Symptoms of grain discoloration on rice panicles (-Si).B, healthy
panicle grown at (+ Si) in rice plants .

28. Effect of silicon in rice seedling under abiotic stress
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Fig. Physiological, Biochemical and Anatomical effect of silicon under Abiotic stress
Zhang et al, 2015

29. Effect of silicon on heavy metal stress
Fig. 2. Schematic model of silicon interactions with arsenic and cadmium (and iron) from
the soil solid phase through to leaf epidermal cells.
Meharg et al,2015

30. Fig: Interaction between intercellular Si and heavy metals.
Silicon helps in reducing heavy metal stress in plant cell
Mohamed et al,2015

32. Fig. Effect of Silicon on Photosynthesis in Rice under High-Zinc Stress
Liang et al,2014

33. Fig. Silicon enhance thickness of root epidermal cell under high cadmium stress.
EFFECT OF SILICON ON ROOT ANATOMY
Zhang et al, 2015

34. Effect of silicon on rice leaves resistance to ultraviolet -b
Fig:Without UV-B irradiation both the silicon-treated (Fig.a) and non treated
leave(Fig.b) showed no necrotic spots, after 30 h exposure to UV-B radiation,the
silicon-deficient leaves exhibited many brown spots(Fig.c),but silicon treated leaves
does not show any damage due to UV-B radiation(Fig.d).

35. Fig: Schematic mechanism of the interaction of Si treatment and salt stressed plants.
Mahbod et al,2015
SILICON OVERCOME SALT STRESS IN PLANTS

36. EFFECT OF SILICON ON
SEED GERMINATION IN
NaCl STRESS
Fig: silicon increase seed germination percentage during NaCl stress

37. Fig: Effect of silicon on different concentration in NaCl stress

38. Fig. production of reactive oxygen species and defense mechanism in chloroplasts
during Salt stress.
ROLE OF SILICON FOR MITIGATION OF OXIDATIVE STRESS
Sowbiya et al, 2014

40. EFFECT OF SILICON SOLUBILIZERS ON YIELD, PEST
AND DISEASE RESISTANCE 2014
40

41. Different growth attributes were recorded.
Two different form of silicon solubilizers were
applied (solid and liquid).

42. GROWTH ATTRIBUTES MAXIMUM(M)/ MINIMUM(m)
Plant height Solid and liqid(M)
Leaf area index Solid and liquid(M)
Leaf dry weight Liquid silicon solubilizer (M)
Culm dry weight Liquid silicon solubilizer (M)
Total dry weight Liquid silicon solubilizer (M
YIELD ATTRIBUTES
Panicle/m2 Liquid silicon solubilizer (M)
Spikelet’s/panicle Liquid silicon solubilizer (M)
Grain/panicle Liquid silicon solubilizer (M)
1000-grain weight Solid silicon solubilizer (M)
Economic yield Solid silicon solubilizer (M)
Harvest index Solid silicon solubilizer (M)
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43. 1. Silicon application enhanced the plant growth,
quality and yield.
2. Increased plant resistance to biotic and abiotic
stress
3. Decline the rate of damage done by pathogen
and insects.

44. Conclusion
 Silicon plays a vital role to induce growth, development
and high yield production in plants
 Silicon induced accumulation of phenolic compounds or
phytoalexin
 Silicon is effective to reduce salt, oxidative, drought and
heavy metal stresses
 Deposition of silica on epidermal cells of leaves act as
mechanical barrier for insects and pathogens
 Silicon uptake from lateral roots of rice plant plays a key
role in rice resistance to brown spot
 Application of silicon improves seed germination
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