SILICON
2nd
‘The biochemistry of silicon in planta is a riddle
wrapped
pp in a mystery
y
y inside an enigma.’
g
Epstein, 2001
What is Soluble Silicon?
S l bl Silicon
Soluble
Sili
(Mono
(Mono(M
-Silicic
Sili i A
Acid)
id) iis th
the plantplant
l tavailable portion of the silica that makes up over
40% of soil chemistry. It is generally present in
plant tissues in amounts similar to that of
macronutrients
t i t (N
(N, P
P, K
K, C
Ca, Mg,
M S) and
d iin some
grasses and grass family crops, often at higher
levels than other macronutrients.
In addition:
ƒ Plants grown in soils with low soluble silicon levels
have a greater susceptibility to disease, drought stress
and other plant stresses
ƒ Silicon has been shown to reduce phosphorus leaching
while at the same time increasing phosphorus plant
availability.
ƒ Silicon’s activity in the soil matrix has been proven to
improve micronutrient uptake (boron,
(boron copper,
copper iron,
iron
manganese, zinc) and reduce toxic metal uptake
(aluminum) as well as sodium.
Biochemical/genetic role of
silicon?
ƒ Silicic acid is absorbed by plants to be
continuously transformed into insoluble polymers
ƒ Soluble silicon has been detected inside the cell, in
the cytosol,
y
in chloroplastic membranes as well as
in association with RNA and DNA.
ƒ This
Thi information
i f
ti suggests
t that
th t silicon
ili
can have
h
a
series of intracellular sites of action to explain its
g properties
p p
in plant
p
disease resistance
stimulating
Where does soluble Si come from,
and
d why
h d
do d
deficiencies
fi i
i
occur?
?
ƒ In the soil, Silica is generally abundant as
mineral quartz and clays, but its abundance
in soluble form (mono(mono-silicic acid) is highly
variable.
i bl
ƒ Continuous cropping of land
land, natural
weathering, or inherently deficient soils can
be causes of deficiency.
ƒ Plants take up silicon into their root and
shoot tissue,
tissue but it is not returned through
biodegradation.
AAPFCO News
ƒ AAPFCO approval
pp
as a beneficial
substance: any substance or
compound other than primary,
secondary,
d
and
d micro
i
plant
l t nutrients
t i t
that can be demonstrated by
scientific research to be beneficial to
one or more species of plants, when
applied
pp
exogenously.
g
y
Known Impacts on Plant Health
ƒ Increases cell wall strength
ƒ
ƒ
ƒ
ƒ
ƒ
ƒ
ƒ
ƒ
ƒ
Results in increased wear tolerance
Disease resistance
Insect resistance
More upright
g growth
g
and rigidity
g
y
Increased shoot and root density, resulting
in higher yields
Regulates uptake of toxic elements
Increases heat tolerance
Slows transpiration
c eases CEC
C C making
a
g other
ot e nutrients
ut e ts
Increases
more available
Direct Role of Silicon in Plant Health
ƒ Tissue analysis indicates that silicon makes
up between 0.2 and 10
10%
% of a plants dry
weight.
ƒ Its
It association
i ti
with
ith cell
ll wall
ll proteins
t i
indicates an active biochemical function.
ƒ It is prominent in cell walls as solid
amorphous silica, providing a structural
barrier to pathogens.
ƒ Studies suggest it is translocated from roots
t shoots.
to
h t
The mechanical barrier hypothesis
CuticleCuticle
-silica double layer (Yoshida et al., 1962)
conidium
cuticle
Silica layer
Outer cell
wall
Epidermal
E
id
l
cell
No infection in the
epidermal
id
l cell
ll
Katy (resistant)
SiTime (h)
0
12
24 36
48
M201 (susceptible)
Si+
60
72
96
0
12 24
36
Si+
Si-
48
60 72
96
0
12 24 36 48 60 72 96
0
12
24 36 48 60
72 96
PR-1
rRNA
5. 0
4. 0
Relative
Intensity
PR-1
3. 0
2. 0
1. 0
0. 0
0
12
24
36
48
60
72
96
Time after inoculation ((h))
Katy Si-
Katy Si+
M201 Si-
M201 Si+
Source: adapted from Rodrigues et al., 2005
Katy (resistant)
SiTime (h)
0
12
24 36
48
M201 (susceptible)
Si+
60
72
96
0
12
24
36
48
Si+
Si60
72
96
0
12 24 36 48 60 72 96
0
12
24 36 48 60
72 96
POX
rRNA
Peroxidase
1. 2
1. 0
Relative
Intensity
0.8
0.6
0.4
0.2
0.0
0
12
24
36
48
60
72
96
Time after inoculation (h)
Katy Si-
Katy Si+
M201 Si-
M201 Si+
Source: adapted from Rodrigues et al., 2005
Katy (resistant)
SiTime (h)
0
12
24 36
48
M201 (susceptible)
Si+
60
72
96
0
12 24
36
48
Si+
Si60
72
96
0
12 24 36 48 60 72 96
0
12
24 36 48 60
72 96
Glu
rRNA
2.0
E-1,3-glucanase
1. 5
Relative
Intensity
1. 0
0.5
0.0
0
12
24
36
48
60
72
96
Time after inoculation (h)
Katy Si-
Katy Si+
M201 Si-
M201 Si+
Source: adapted from Rodrigues et al., 2005
HPLC analysis of SF5 from FII of non-inoculated and
inoculated plants amended or not with silicon
0.6
Si-
0.4
non-inoculated
0.6
inoculated
Si-
46 min
04
0.4
0.2
0.2
0.0
0.0
Momilactone A
0
40
45
50
0.6
Si+
0
55
non-inoculated
40
45
0.6
0.4
0.4
0.2
0.2
0.0
0.0
50
55
inoculated
Si+
47 min
Momilactone B
0
40
45
50
Minutes
55
0
40
45
50
Minutes
55
Source: adapted from
Rodrigues et al., 2004
Conclusion
Si-
Si+
Low levels of
momilactones
Higher levels of
momilactones
and
High level of blast severity
z
and
Low level of blast severity
Influence of silicon on Bipolaris leaf spot in bermudagrass
+Si
% Leaff spot severity
-Si
120
100
80
60
40
20
0
+ Si
- S
Si
1
2
3
4
5
Days After Inoculation
Source: adapted from Datnoff and Rutherford, 2004
Conclusions
"
In Si+ plants of M201, a differential accumulation of
transcripts from glucanase, peroxidase and PR-1 besides the
participation of phenolics counteracted the spread of the
invading fungus and the damage that it caused to the leaf
tissues.
Beneficial Effects of Si on Crop Growth in Relation to Biotic and Abiotic
Stresses
Alleviates Excess N Stress
Alleviates
ll i
Water Stress
Alleviates
ll i
Salt
l Stress
Improves Light Interception
Decrease Transpiration
Increases Resistance to Biotic Stress
Keeps Leaves Erect
Detoxify Mn
Prevents Lodging
Alleviates Water Stress
Decreases Transpiration
Increases Strength of Stem
Changes Mn distribution
D
Deposition
iti on St
Stem
Deposition on Leaves
Deposition on Hull
Alleviates P excess stress
Shoot
Root
nSiO2
Sili
Silica
nSi(OH)4
Silicic acid
Decreases P uptake
nSiO2
Silica
Alleviates P deficiency stress
Improves Internal P availability
Decreased Mn uptake
Alleviates Mn excess stress
Soil Solution
nSi(OH)4
Silicic acid
Forms Al-Si Complexes
Detoxify Al
Introducing
I t d i
EXCELLERATOR
About Excell Minerals
ƒ Privately held global
corp. with new
ownership since 2003.
ƒ Headquartered in
Pittsburgh, PA.
ƒ Excell Minerals is a
worldwide leading
producer of products
for the agricultural,
metals, turf, and
cementt industries.
i d t i
EXCELLERATOR
Excellerator Chemical Analysis:
¾
¾
¾
¾
¾
¾
¾
¾
¾
¾
¾
¾
¾
¾
Silicon Supplement:
Supplement: 39.3%
CaMgSiO4 - 5.8%
Ca3Mg(SiO4)2 - 17.9%
Ca2MgSiO7 - 8.0%
Ca2SiO4 - 7.6%
Micronutrient Package:
Package:
Calcium (Ca) – 24%
Iron (Fe) – 1.8%
Copper (Cu) – 0.05%
0 05%
Boron (B) – 0.02%
Magnesium (Mg) – 6%
Manganese
g
(Mn)
(
) – 0.7%
%
Zinc (Zn) – 0.05%
Molybdenum (Mo) - 0.004%
EXCELLERATOR
Granular product
SGN 100 and 200
R dil soluble
Readily
l bl
Silicon, Calcium, and Magnesium
driven
ƒ Higher in Silicon (39%) than any
known
o
co
competitor
pet to
ƒ
ƒ
ƒ
ƒ
What Makes EXCELLERATOR
Unique?
ƒ Excellerator’s custom blend of
nutrients enhances any turf
fertility
y program.
p g
ƒ The high level of soluble silicon
in Excellerator is its truly unique
attribute.
attribute
EXCELLERATOR
ƒ Hydrolyzes in the soil to form mono
and polypoly-salicic acids, which is the
form the p
plant takes up
p
ƒ Available in the soil for 12 months,
although the majority is taken up in
the first 6 months
Toxic Elements
ƒ Mn uptake is not affected, but
distribution is
ƒ Mn deposits can cause spotting on
leaves
ƒ Si prevents this by distributing it
throughout the plant
ƒ Sodium toxicity reduced
Improved Nutrient Uptake
Winter Wheat Tissue Analysis Silicon Vs. Phosphorus
0.37
0.35
0 33
0.33
P (% )
ƒ Monosilicic acid
concentrations
in some soils
have been
associated with
a 10
10--80%
80%
increase in
available P and
increased plant
P uptake and
yield.
ƒ Reduces
phosphorus run
off in sandy
soils
soils.
ƒ Improves CEC
0.31
0.29
0.27
0.25
0.40
0.50
0.60
0.70
0.80
Si (%)
Aglime 1
Aglime 2
Excellerator
0.90
1.00
Effect of Silicon Fertilizer on the
Root Zone
Dr. V. Matichenkov
Matichenkov—
—University of Florida Rice And Citrus Studies
Protection Against Temperature Extremes
Photograph
g p of creeping
p g bentgrass
g
exposed
p
to high
g temperature.
p
Plants had been grown for 55 days at 20 qC , and then exposed to
a temperature of 35 -40 qC under constant light and humidity for
20 days. The growth of creeping bentgrass applied silicon sources
was similar. However, most of the control plants grown 35 qC
above had died by day 20.
Source: adapted from Lijun, et. al. 2004.
Application Recommendations
ƒ Soil testing should
be done
ƒ Standard
St d d rates:
t
Initial application of
25lb/M on greens
tees,
tees fairways and
sports turf.
ƒ Follow with 10 lbs.
lbs
topdressing 30
days apart to
achieve 50lb/M per
year
Marketing EXCELLERATOR
EXCELLERATOR
ƒ Disease
Di
resistance
i t
ƒ Reduced chemical
applications?
li ti
?
ƒ Reduced water
needs
d
ƒ Increased wear
tolerance
t l
ƒ Saves labor in
other
th areas
Added Selling Points
Marketing
g EXCELLERATOR
C
O
ƒ Excellerator is 39
39.3%
3% soluble Silicon
ƒ Competition is much lower in silicon
content
t t (33%)
ƒ Breaks down easier than competitor
ƒ Available in 50 lb bags and 1000#
bulk bags
g
ƒ Increases nutrient availability while
cutting other fertilizer costs
Research
The evaluation of Silicon has been ongoing
g
g for the p
past 30 years.
y
•Dr. G. Korndörfer, University of Uberlandia, Brazil working on
wet-land rice in Florida concluded:
• In 19 out of 28 field experiments silica had a positive effect
on yield.
• Considering only sites with Si response, average increased
yield was 1007 Kg/ha (932 lbs/A)
• Dr. Emanuel Epstein, University of California (Davis) has
published extensively on silica and plant health and has verified
that silicon absorbed by plants:
· Is deposited in and strengthens cell walls
· Results in plants being more resistant to insect attack,
disease, and lodging
· Increases yields
•Dr.
Dr.
•Dr.
•Dr.
•Dr.
J Chen- University of Florida
James Menzies
Menzies- University of Laval, CA
Lawrence Datnoff- University of Florida
Wakar Uddin- Penn State University
Questions?