Influence of Silicon on Cadmium uptake in durum wheat cultivars

Muhammad Arifin Sandhi

Masters Student, EcologyStockholm UniversitySE- 10691, Sweden

Background

Cd is a non-essential metal for plants, present in the soil at very low concentration.

Occurance of Cd by industrial activity, pesticide residues, electronic waste, mining, swedge sludge deposition.

Cd linked with food chain and cause diseases like cancer,bone fracture,hypertension, etc.

In Sweden, the half of total Cd intake in the human body by potato (43%) and wheat (40%)

(Greger & Löfstedt, 2004)

DurumWheat (TriticumturgidumL var.)

• Developed in Late Bronze Age(6000-7000 BC) and difference from bread wheat genome (2n=6x) where durum (2n=4x)

• Evidence to uptake Cd in durum in US, Canada and Sweden.

• Two common varities in Sweden, Helidur (low accumulator)and Grandur(high accumulator).

(Greger & Löfstedt, 2004)

Silicone

• Silicon (Si) helps the plant to recover them from biotic (pest and pathogen) and abiotic stress (heavy metal).

• Some cereal crops under Gramineae and Cyperaceae can uptake high amount of Si.

• Si helps initiation of tolerance mechanism against toxic

metals.

(Gong et al., 2008)

Questions?

Influence of Silicon

on Cd uptake in respect of time. Net uptake of Cd in root regions. Translocation percentage between two durum wheat

cv.

Materials

Durum wheat cultivars; helidur and grandur

Cd isotope (42 nM) and half life 453 days.

Potassium Silicate

Methods

• The wheat seedlings are cultivated in climate chamber on hydroponics medium for 2 weeks.

• There are four treatments of Si (0, 0.5, 2, 5 nM) with 3 replications and each replicate has 4 plants in each.

• After addition of Cd, collect the solution from medium in respect of time (0 min, 12 min,24 min, 36 min, 1 h, 4 h, 20 h, 48 h) and analysed in Scintillation machine (DPM) with addition of Emulsifier.

• After 48 hours plant biomass collected, wet digestated and analysed in scintillation machine.

Result

Cd Uptake

0 min 12 min 24 min 36 min 60 min 240 min 1200 min 2880 min

-10000

-5000

0

5000

10000

15000

20000

25000

0 mM

0.5 mM

2 mM

5 mM

Time (Min)

Cd u

ptak

e in

Hel

idur

(DPM

/ g

Root

DW

)

0 min 12 min 24 min 36 min 60 min 240 min 1200 min 2880 min-5000

0

5000

10000

15000

20000

25000

0 mM0.5 mM2 mM5 mM

Time (Min)

Cd u

ptak

e in

Gra

ndur

(DPM

/ g

DW)

Results

Cd Uptake/minute

12min24min

36min60min

240min

1200min

2880min

-800

-600

-400

-200

0

200

400

600

800

1000

1200

0 mM0.5 mM2 mM5 mM

Time (Minute)

Cd u

ptak

e in

Hel

idur

DPM

/(g

DW*m

in)

12min24min

36min60min

240min

1200min

2880min

-200

-100

0

100

200

300

400

500

600

700

0 mM0.5 mM2 mM5 mM

Time (Minute)

Cd u

ptak

e in

Gra

ndur

DPM

/ (g

DW

* m

in)

Results

Net Uptake Cd by roots

0 0.5 2 50

200

400

600

800

1000

1200

1400

1600

HelidurGrandur

Si Concentration (mM)

Net

upt

ake

of C

d DP

M/(

g DW

root

)

Results

Translocation Percentage

0 0.5 2 50

10

20

30

40

50

60

70

80

90

100

HelidurGrandur

Si concentration (mM)

Cd tr

anslo

catio

n to

shoo

ts (%

)

Discussions

Uptake is higher in grandur cv, but uptake rate/min is faster in helidur cv with increase of Si treatments.It is probably binding of available Cd in the solution with root cell proteins and make it inactive complex molecules .

The net uptake of Cd in root decreased with increase of Si application. This decrease trend is more higher in helidur than grandur.This findings suggested that higher dose of Si application reduce Cd uptake in the roots of helidur.

Si application reduce the translocation percentage of Cd in shoots of helidur than grandur.The common trend of metal sink root>shoot>grain. As Si deposited in the leaf area of wheat, so plant leaf can avoid and reduce the Cd in the shoot with help of Si.

Conclusions

• Research needs for helidur as Si decrease the accumulation of Cd in both root and translocation in shoot.

• Carry out research in field level because hydroponics medium can cause higher stress than field condition.

Acknowledgement

Docent Maria Greger&

FL Tommy Landberg

Questions?

Tack så mycket !