i. cakmak sabanci university istanbul , turkey cakmak@sabanciuniv
DESCRIPTION
Detrimental Effects of Glyphosate on Nutritional Status of Plants with Micronutrients. I. Cakmak Sabanci University Istanbul , Turkey [email protected]. Glyphosate: extensively applied herbicide. Increasing usage in minimum- and no-tillage agricultural practices - PowerPoint PPT PresentationTRANSCRIPT
I. Cakmak Sabanci University Istanbul, Turkey
Detrimental Effects of Glyphosate Detrimental Effects of Glyphosate on Nutritional Status of Plants on Nutritional Status of Plants
with Micronutrientswith Micronutrients
Glyphosate:Glyphosate: extensively applied herbicide
• Increasing usage in minimum- and no-tillage agricultural practices
• Extensive application on RR crops
.
In regions with extensive use of glyphosate there are increasing reports on:
• reductions in growth and yield, • increases in disease problems,• increased use of insecticides and fungicides,• inhibition of N fixing bacteria• increased use of foliar micronutrient fertilizers• micronutrient deficiencies
Particular micronutrient deficiencies induced by
Glyphosate: Manganese and Iron Deficiencies
Repeated use of glyphosate induces Fe and Mn deficiencies in soybeans
in USA
(Photo: Prof. Don Huber)
(areas which are not treated with glyphosate)
+ gyphosate
+ seed Fe treatment
+ gyphosate
– seed Fe treatment
- gyphosate
+ seed Fe treatment
Photo: N.C. Hansen, Fort Collins, USA
Glyphosate-induced Fe-deficiency chlorosisGlyphosate-induced Fe-deficiency chlorosis
(Jolley et al., Soil Sci Plant Nutr. 50, 793-981, 2004)
visual chlorosis scrore grain yield Treatment (1=green to 5 =severe) (t/ha)
– Fe + Fe* – Fe + Fe*
Control 3.1 2.8 1.01 1.70 (no herbicide)
Glyphosate 3.7 3.3 0.27 0.61
* 50g Fe/ha as FeEDDHA applied to seeds
Interaction of seed applied Fe and glyphosate application on Fe deficiency chlorosis in soybeans; Minnesota, USA
(Jolley et al., Soil Sci Plant Nutr. 50, 793-981, 2004)
Foliar and Soluble Micronutrient* Sales in USA
0
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
B Cu Fe Mn Zn
20002001200220032004
(*represents approx 30% of US Sales)
(Courtesy of Prof. P. Brown, UC Davis)
RoundUp Ready Corn, Soy
Glyphosate is toxic to plants whether from a drift or residues in soil
http://www.uky.edu/Ag/Tobacco/Pages/RoundupFloat.html
A significant amount of glyphosate applied to target plants reaches the soil as a result of direct contact, wash off from leaves and exudation from roots of the treated weeds.
entweb.clemson.edu.
Up to 10 % of the applied glyphosate move to non-target plants
no Glyphosate
withGlyphosate
Application of glyphosate on target plants (weeds)/glyphosate resistant cultivars; very quick uptake by leaves.
Rapid translocation of glyphosate from shoot to root
REMEMBER
Glyphosate is highly phloem mobile
Release of glyphosate into therhizosphere
Marschner and Römheld, 1995; Plant and Soil
Rhizosphere/SoilPlasma
MembraneApoplasm Cytoplasm
H+
RFeIII ChelateChelator
Reductants
(Chelators)
H+
FeII
FeIII
FeIII
FeIII
FeIII
TR
PUMP
Adaptive Root Responses of Strategy-I Plants to Fe Deficiency
R: Ferric ReductaseR
Effect of iron deficiency in cucumber on pH decreasing and reducing capacity of the roots
+Fe +Fe-Fe-Fe
Romheld et al., 1981
Time dependent inhibition of ferric reductase activity in Fe-deficient sunflower plants (+Glyp: 1.89 mM glyphosate
or 6% of the recommended rate for weed control)
0
20
40
60
80
-Glyp. +Glyp.6h
+Glyp.12h
+Glyp.24h
-Glyp.+Fe
Fe
redu
ctio
n ca
paci
ty
(µm
ol F
e(II
) g
- 1 r
oot
dry
wt
3 h
- 1)
LSD0.05
Fe deficient
Control (+Fe)
Ozturk et al., 2007
Effect of Glyphosate on Ferric Reductase
Dose dependent inhibition of ferric reductase activity by glyphosate (+Glyp: 0.32, 0.95 and 1.89 mM
0
20
40
60
80
-Glyp. +Glyp.0.32 mM
+Glyp. 0.95 mM
+Glyp. 1.89 mM
-Glyp. +Fe
Fe
redu
ctio
n ca
paci
ty
(µm
ol F
e(II
) g
- 1 r
oot
dry
wt
3 h
- 1)
LSD0.05
Fe deficient
Control (+Fe)
Ozturk et al., 2007
Foliar applications of glyphosate (Glyp) at 0.32 mM, 0.95 mM and 1.89 mM for 24h.
Ozturk et al., 2007
Staining of Ferric Reductase Activity
GLYPHOSATE
Fe Deficient Plants
-Fe -Fe +Glyp (1.89 mM)
Effect of foliar applied of glyphosate (1.89 mM ) for 24hon ferric reductase activity.
Ozturk et al., 2007
Shikimate accumulation(µmol g -1 FW)
0
3
6
9
12
15
ShootShoot
Do
se D
epen
den
t S
hik
imat
e A
ccu
mu
lati
on
Ozturk et al., 2007
0
2
4
6
8
Shikimate accumulation(µmol g -1 FW)
RootRoot
Ozturk et al., 2007
Do
se D
epen
den
t S
hik
imat
e A
ccu
mu
lati
on
Shoot Root
Shikimate accumulation(µmol g -1 FW)
0
3
6
9
12
15
0
2
4
6
8
Time Dependent Shikimate Accumulation
Ozturk et al., 2007
ROOT UPTAKE TRANSLOCATION TO SHOOT
0
5
10
15
20
25 59Fe
LSD0.05=7.0
0
200
400
600
800 59Fe
LSD0.05=108
0
25
50
75
100
12554Mn
LSD0.05=3.6
0
300
600
900
120054Mn
LSD0.05=22.5
0
25
50
75
10065Zn
LSD0.05= ns
0
750
1500
2250
300065Zn
LSD0.05= ns
Ro
ot
up
tak
e r
ate
(
nm
ol
g-1 r
oo
t d
ry w
t 4
h-1)
Sh
oo
t tr
an
slo
ca
tio
n r
ate
(
nm
ol
g-1 r
oo
t d
ry w
t 4
h-1)
Control Glyphosate Control Glyphosate
Effect of 1.89 mM glyphosate (equivalent to 6 % of the recommended dosage for weed control in the field) on root uptake and shoot translocation of 59Fe, 54Mn and 65Zn in sunflower plants.
Eker et al., 2006: J. Agric. Food Chem. 26, 10019 -10025
Short-Term Experiments:Glyphosate inhibits root uptake and
root-to-shoot transport of micronutrients
59Fe
54Mn
65Zn
Root Uptake Translocation
Rhizosphere/Soil PlasmaMembrane
PHYTOSIDEROPHORES
TRFeIII-PS
TR: Transporter Protein
ZnII-PS
Apoplasm Cytoplasm
FeIII
FeIII
ZnII
ZnIIFeIII-PSZnII-PS
Adaptive Root Responses to Iron and Zinc Deficiencies in Cereals
Marschner and Römheld, 1995; Plant and Soil
Biosynthetic Pathway of Mugineic Acid Family Phytosiderophores
H3CS NH2
COOH
NH NH2
COOH COOHCOOH
N
NH O
COOH COOHCOOH
N NH OH
COOH COOHCOOH
N
OH
NH OH
COOH COOHCOOH
N
3"-oxo acid
NH OH
COOH COOHCOOH
NHHO
NH OH
COOH COOHCOOH
NHO
OH
NH OH
COOH COOHCOOH
NHO
S-adenosyl-methionine
NAAT
NAS
NH OH
COOH COOHCOOH
NHO
OH
Nicotianamine
methionine
DMA
mugineic acid family phytosiderophores
AVA
MA
HMA epiHMA
epiHDMA
IDS3
IDS3
IDS2
IDS2
DMAS
SAMS
Mugineic Acid Family
Mori et al., 1990
Fe OH FeNH2
Fe3+-Deoxymugineic acid Fe3+-Nicotianamine
Similar Stereochemical Structure between Fe3+-DMA and Fe3+-NA
Mori, et al, 1990
PhytosiderophorePhytosiderophoreReleaseRelease fromfrom RootsRoots
0
40
80
120
160
Ph
yto
sid
ero
ph
ore
re
lea
se
(nm
ol P
S p
lan
t-1 3
h-1)
+Fe
-Fe, 0% Glyp
-Fe, 1% Glyp
-Fe, 3% Glyp
-Fe, 9% Glyp
+Fe -Fe Ozturk et al., 2008
Phytosiderophore Release from Wheat Roots
0
40
80
120
160
Ph
yto
sid
ero
ph
ore
re
lea
se
(nm
ol P
S p
lan
t-1 3
h-1)
+Fe
-Fe, 0% Glyp
-Fe, 1% Glyp
-Fe, 3% Glyp
-Fe, 9% Glyp
Glyphosate ApplicatonOzturk et al., 2008
Control (+Fe, -Glyp)
-Fe, -Glyp -Fe, 1% Glyp
-Fe, 3% Glyp -Fe, 9% Glyp
Control (+Fe, -Glyp)
-Fe, -Glyp -Fe, 1% Glyp
-Fe, 3% Glyp -Fe, 9% Glyp
0.0
0.1
0.2
0.3
0.4
Mob
ilize
d Z
n (µ
g g-1
soi
l)
Mob
ilize
d Z
n, µ
g -1
soil
Mobilization of Zn from Calcareous Soil by Phytosiderophores
Glyphosate ApplicationOzturk et al., 2008
0.0
0.1
0.2
Mob
ilize
d M
n, µ
g -1
soil
Control (+Fe, -Glyp)
-Fe, -Glyp -Fe, 1% Glyp
-Fe, 3% Glyp -Fe, 9% Glyp
Control (+Fe, -Glyp)
-Fe, -Glyp -Fe, 1% Glyp
-Fe, 3% Glyp -Fe, 9% Glyp
Mobilization of Mn from Calcareous Soil by Phytosiderophores
Glyphosate ApplicationOzturk et al., 2008
Application of glyphosate on target plants (weeds)/glyphosate resistant cultivars; very quick uptake by leaves.
Rapid translocation of glyphosate from shoot to root
REMEMBER
Glyphosate is highly phloem mobile
Release of glyphosate into therhizosphere
Induction of Fe deficiency chlorosis in non-target plants (sunflower)
Glyphosate application to target plants (soybean)
Development of Fe deficiency symptoms in non-target plants …
Glyphosate applied to target plants
is released into the rhizosphere
SoybeanTarget
SoybeanTarget
SoybeanTarget
SoybeanTarget
SunflowerIndicator
SunflowerIndicator
(Neumann et al., 2005, J. Plant Dis. Prot.)
Inhibited Mn acquisition by non-target plants (sunflower) grown in nutrient solution together with glyphosate treated target plants (soybean) for 2, 4 and 6 days.
54Mn in shoots
Glyphosate released in the rhizosphere reduces Mn uptake
Neumann et al., 2005, J. Plant Dis. Prot.
KS 4202 RR
KS 4202
Significantly lower Mn uptake/accumulation in RR-soybeans
(B.Gordon, 2006; Kansas State Univ.)
Inhibition of MnO2 Reduction in Soil-filled Rhizoboxes after Glyphosate Treatment to Target Plants (soybean)
(Neumann et al., 2005)
Control + Glyphosate
MnO2 Reduction in Soil-filled Rhizobox Culture of sunflower (non-target) and RR-Soybean with and without foliar Glyphosate spray
Glyphosate Reduces Grain Mn, Mg and Ca
Glyphosate Application, %Glyphosate Application, %
0 0.3 0.6 0.9
0.0
2.0
4.0
6.0
8.0
control 0.3 0.6 0.90
2
4
6
8
10
12
control 0.3 0.6 0.90
4
8
12
16
20
control 0.3 0.6 0.9
Dry
mat
ter
yiel
d, g
pla
nt-1
Glyphosate treatment, % of recommendedGlyphosate treatment, % of recommended
Grain Straw Whole plant
GGrain, straw and whole plant rain, straw and whole plant ddryry matter yield as matter yield as affected by drift rates of glyphosate in soybeanaffected by drift rates of glyphosate in soybean
Glyphosate Applied: 3 Times; one before flowering and 2 times after flowering
Control 0.3 0.6 0.9 Control 0.3 0.6 0.9 Control 0.3 0.6 0.9
Yazici et al., 2008
Glyphosate applied 3 times before flowering
Gra
in c
onc
ent
ratio
n,
%
Glyphosate treatment, % of recommended
K Mg Ca
Grain concentration of K, Mg and Ca as affected by drift rates of glyphosate in soybean
0.6
0.9
1.2
1.5
1.8
control 0.3 0.6 0.90.10
0.15
0.20
0.25
0.30
control 0.3 0.6 0.90.2
0.3
0.4
0.5
control 0.3 0.6 0.90 0.3 0.6 0.90 0.3 0.6 0.90 0.3 0.6 0.9
GlyphosateGlyphosate treatment, % of recommendedtreatment, % of recommended
K Mg Ca
Yazici et al., 2008
Gra
in c
once
ntra
tion,
m
g kg
-1
Grain concentration of Grain concentration of FeFe, M, Mnn and and ZnZn as as affected by drift rates of glyphosate inaffected by drift rates of glyphosate in soybeansoybean
Fe Mn Zn
30
40
50
60
70
80
90
100
control 0.3 0.6 0.930
40
50
60
70
80
control 0.3 0.6 0.920
30
40
50
60
control 0.3 0.6 0.9
Glyphosate treatment, % of recommendedGlyphosate treatment, % of recommended
0 0.3 0.6 0.9 0 0.3 0.6 0.90 0.3 0.6 0.9
Fe Mn Zn
Yazici et al., 2008
Seed Mn and Ca very importantfor seed viability and seedling vigour
0
20
40
60
80
100
120
140
control 0.3 0.6 0.90
200
400
600
800
control 0.3 0.6 0.9
Dry matter yield of young Dry matter yield of young andand old leaves old leaves of of soybeansoybeanplantsplants as affected by drift rates of glyphosateas affected by drift rates of glyphosate
Young leaves Old leaves
Dry
mat
ter
yiel
d,
g pl
ant-1
GlyphosateGlyphosate treatment, % of recommendedtreatment, % of recommended
0 0.3 0.6 0.90 0.3 0.6 0.9
Yazici et al., 2008
K Mg Ca
Concentration of K, Mg and Ca in soybean oncentration of K, Mg and Ca in soybean leaves as affected by drift rates of leaves as affected by drift rates of glyphosateglyphosate
Leaf
conc
entr
atio
n, %
1.5
2.0
2.5
3.0
3.5
control 0.3 0.6 0.9
0.2
0.3
0.4
0.5
0.6
0.7
control 0.3 0.6 0.9
0.6
0.9
1.2
1.5
1.8
control 0.3 0.6 0.9
Glyphosate treatment, % of recommendedGlyphosate treatment, % of recommended
0 0.3 0.6 0.9 0 0.3 0.6 0.9 0 0.3 0.6 0.9
Hande et al., 2008
Hande et al., 2008
Plants with low Mg are highly Plants with low Mg are highly sensitive to glyphosatesensitive to glyphosate
Hande et al., 2008
Plants with low Mg are highly Plants with low Mg are highly sensitive to glyphosatesensitive to glyphosate
What is the effect of Glyphosate??
Glyphosate binds with the cations to form a strong complex which is not bio-available.
Only unbound glyphosate act as a herbicide. www.loveland.co.uk/ Gifs/X-Change-du-pont.gif
Control GlyphosateGlyphosate+ Calcium
Effect of Glyphosate with and without calcium in the tank
Effectiveness of Glyphosate
GlyphosateGlyphosate binds with the cations to form a strong complex which is not bio-available. Only unbound glyphosate act as a herbicide.
Conclusions
• Routine glyphosate use in agricultural systems results in considerable side effects on plant growth and mineral nutrition of plants
• Glyphosate is antagonistic to the uptake, transport and accumulation (tissue concentration) of Fe,Mn, Ca and Mg possibly due to the formation of poorly soluble glyphosate-metal complexes (??)
Conclusions-cont
• Glyphosate impairs genetic adaptation mechanisms of plants to Fe deficiency
• Plants grown under low Mg are very sensitive to glyphosate
• A new risk assessment for glyphosate is urgently needed,
Root Tips:Co-localization of Ferric
Reductase and Glyphosate Accumulation
Leading 10 Health Risk Factors in Developing Countries, % Cause of Disease Burden
Underweight 14.9%
Unsafe sex 10.2%
Unsafe water 5.5%
Indoor smoke 3.7%
Zinc DeficiencyZinc Deficiency 3.2%3.2%Iron deficiencyIron deficiency 3.1%3.1%Vitamin A def. 3.0%
Blood pressure 2.5%
Tobacco 2.0%
Cholesterol 1.9%WHO, 2002
Copenhagen Consensus-2004Copenhagen Consensus-2004Worldwide Panel of Distinguished Economists
including Nobel Prize-Winners
Top Four Global Challenges
Source:: http://www.copenhagenconsensus.com)
• Control of HIV/AIDS• Providing micronutrients (Fe, Providing micronutrients (Fe, Zn..) Zn..) to human populationsto human populations• Trade Liberalization• Control of Malaria
Interference of glyphosate with root uptake and transport ofmicronutrients may also represent a potential threat to human nutrition and human health
T. Tesfamariam Fanghua Ye C. Weishaar
K. Stock-de Oliveira Souza E. Landsberg S. Kohls University Hohenheim (U.H.)V. Römheld T. Yamada I. Cakmak
(S. Bott: Uni.Hohenheim)
L. Ozturk Sabanci UniversityG. Neumann
Sabanci Sabanci UniversityUniversity
Obrigado…
-Glyp. 208 ± 16 58 ± 8 21.2 ± 1.0
+Glyp. 0.32 mM 202 ± 16 55 ± 8 21.3 ± 0.7
+Glyp. 0.95 mM 208 ± 15 56 ± 11 21.7 ± 1.4
+Glyp. 1.89 mM 194 ± 23 53 ± 9 21.8 ± 2.3
+Fe -Glyp. 226 ± 30 61 ± 13 39.2 ± 1.9
LSD0.05
-Fe
Chloropyll
(mg plant-1) (SPAD)
24 12 2.3
Dry matter productionTreatments Shoot Root
Shoot and root dry matter production and chlorophyll level as influenced from glyphosate application for 24 h
Ozturk et al., 2007
0
3
6
9
12
15
Tot
al c
arbo
hydr
ates
(mg
gluc
ose
equi
v. g
-1 F
W)
Carbohydrates in Apical Parts of Roots
Ozturk et al., 2007
+ Glyphosate
Marschner and Römheld, 1995; Plant and Soil
RhizospherePlasma
MembraneApoplasm Cytoplasm
H+
RFeIII ChelateChelator
Reductants
(Chelators)
H+
FeII
FeIII
FeIII
FeIII
FeIII
TR
PUMP
Root Responses to Fe Deficiency in Strategy-I Plants
NAD(P)H
NAD(P)+
R: Ferric ReductaseR
0
10
20
30
40N
AD
PH
oxi
datio
n(n
mol
min
-1 g
-1 F
W)
Capacity of Roots to Oxidize NADPH
Ozturk et al., 2007
+ Glyphosate
Close Relationship between Fe Deficiency Tolerance and Ferric Reductase Activity in Soybean
Marschner and Romheld, 1995
Soybean Genotypes
Rel
ease
of
chel
atin
g c
om
po
un
ds
(µm
ol
Fe
equ
iv.
g-1 f
resh
wt.
h-1)
0
10
20
30
40
50
60
+Fe
-Fe
Release of Phytosiderophores from Roots Correlate with Tolerance Fe Deficiency Chlorosis
rice sorghum maize oat Wheat
(Römheld & Marschner (1986): Adv. in Plant Nutr 2, 155-204)
Chlorosis resistance