HAL Id: hal-02797006
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Variability in grain cadmium concentration among durum wheat cultivars: impact of aboveground biomass
partitioning
Bofang Yan, Fanny Perrier, Oleg S. Pokrovsky, Christophe Nguyen, Jean-Yves Cornu
To cite this version:
Bofang Yan, Fanny Perrier, Oleg S. Pokrovsky, Christophe Nguyen, Jean-Yves Cornu. Variability in grain cadmium concentration among durum wheat cultivars: impact of aboveground biomass parti-tioning. 18. International Conference on Heavy Metals in the Environment, Sep 2016, Ghent, Belgium. 2016, �10.13140/RG.2.2.30998.55368�. �hal-02797006�
Exposed to 2 nM Cd2+ after transplanting
1ISPA, INRA, Bordeaux Sciences Agro, Villenave d’Ornon, France 2GET, CNRS, Université de Toulouse, Toulouse, France
Variability in Grain Cadmium Concentration among Durum Wheat Cultivars:
Impact of Aboveground Biomass Partitioning
Bofang Yan
1, F Perrier
1, OS Pokrovsky
2, C Nguyen
1and JY Cornu
1Background
Materials
Hypothesis & Objectives
Results
jycornu@bordeaux.inra.fr
To assess the variation of grain Cd concentration among French
durum wheat cultivars.
To test whether the different pattern of aboveground biomass
partitioning affects the grain Cd concentration between cultivars.
8
French Cultivars (×5 repetitions)differing in their aboveground biomass partitioning
Cultivar
: eight French durum wheat
cultivars, no Cdu1 allele;
Plants were trained to develop
4 tillers
from the start of elongation.
Hydroponics
: modified Hoagland’s
nutrient solution at pH 6.0, refreshed
automatically;
Cd
2+was supplied after transplanting
at low dose:
non-toxic, fixed at
2 nM
(to reproduce the level of exposure to Cd found in low
to moderately contaminated agricultural soils [1])
;
𝑮𝒓𝒂𝒊𝒏 𝑪𝒅 = 𝑸𝑪𝒅𝒕𝒐𝒕 × (𝟏 − 𝑹𝑺𝑭 𝑮𝒓𝒂𝒊𝒏 𝑫𝑾 × 𝑮𝑨𝑭 Hypothesis: Straw, which was represented by leaves, compete Cd with Grain 𝑮𝑨𝑭 = 𝜶 × 𝑳𝒆𝒂𝒗𝒆𝒔 𝑫𝑾 𝑮𝒓𝒂𝒊𝒏 𝑫𝑾 −𝜷 𝑮𝒓𝒂𝒊𝒏 𝑪𝒅 = 𝜶 × 𝑸𝑪𝒅𝒕𝒐𝒕 × 1 − 𝑹𝑺𝑭 × 𝑳𝒆𝒂𝒗𝒆𝒔 𝑫𝑾−𝜷 𝑮𝒓𝒂𝒊𝒏 𝑫𝑾 1−𝜷
Grain Cd level
Modelling to Explain the Variability in Grain Cd
The concentration of Cd in the grain (Grain Cd, µg g-1) was modeled
as a function of the grain biomass (Grain DW, g), the amount of Cd taken up by the roots (QCdtot, µg), a root sequestration factor (RSF) and a grain allocation factor (GAF) itself modeled as a function of the ratio between the biomass of leaves and that of grains.
Grain Cd concentration ranged from 0.03 to
0.08 µg g-1 (2.4-fold)
among cultivars and was thus in the same range as that measured in field trials.
The 2.4-fold variation in grain Cd within French lines was NOT explained either by a difference in uptake or by a difference in the root sequestration of Cd.
The model shown in
the equation above
provides a good
prediction of the
intraspecific variation
in grain Cd.
R2 = 0.74 Slope = 0.92*** Intercept = 0.005ns Grai n Cd O b ser ved (µg g -1 D W) Grain Cd Fitted (µg g-1 DW)Uptake and Root sequestration of Cd
The
Leaf Biomass
was the
main factor explaining the
variation in grain Cd
Conclusions
The grain Cd concentration varied 2.4-fold
among French durum wheat cultivars.
The partitioning of aboveground biomass may
influence the concentration of Cd in grain.
Breeding programs tending to reduce the stem
height may promote the accumulation of Cd in
durum wheat grains.
Cd2+ Partitioning aboveground Root-to-shoot Translocation Root uptake
Cd pollution in agricultural soil is a common challenge
around the world. Cereals is a major component of the
human diet. The dietary intake of Cd contaminated
cereals is toxic to humans. This problem is particularly
important in durum wheat (Triticum turgidum L. subsp.
durum) since this species accumulates more Cd than
other commonly grown cereals.
Using low-Cd accumulating cultivars is one approach to
minimize the Cd load in durum wheat grains. This option
first needs to evaluate to what extent the concentration
of Cd in the grain varies among durum wheat cultivars
and to understand the main processes responsible for
this variation.
[1] Sauvé, S. et al Environmental Science & Technology (2000) 34(2), pp. 291-296. The French cultivar
that took up more Cd maybe not the one with higher
concentration of Cd in the grain. Grai n Cd (µg g -1 D W) Wheat Cultivar Medium Cd Low Cd High Cd
X 2.4
Wheat Cultivar Cd upt ak e (µg) Wheat Cultivar R SF (%) There was no significant difference in root sequestration factor (RSF) values among French cultivars.Variation of the explanatory variables of the model
×2.04 Variation of QCdtot QCdtot Den sity Variation of (1-RSF) ×1.63 1-RSF Variation of Grain DW(1-β) Grain DW(1-β) ×1.81 Variation of Leaves DW-β Leaves DW-β ×2.17 Den sity 95% 95% 95% 95% Den sity Grain Cd ©Terre-net Média
Assuming that aboveground
vegetative organs (straw) are
sinks for Cd in competition
with grains during grain filling,
we expect that cultivars
allocating more relative
biomass to the straw (could
be cultivars with longer stems)
would accumulate less Cd in
their grains.
Higher Plant More relative straw biomass Less Biomass partitioned to Straw More Cd allocated to the grain? Shorter Plants Less relative straw biomassClovis, Dakter, Isildur, Miradoux, Nefer, Pescadou, Pharaon, Sculptur
GF-AAS
Cd concentration Grains
Head
structure (Bracts & Rachis) Leaves Stems Roots Harvest at maturity G er m in at io n Pr e -gr ow in g
Transplanting Cultivation Maturity Harvesting
Cd2+
Cd2+
Cd2+
