Youqiang
Fua,^b, Xujian Yang^b, Hong Shen^b,⁎

Ecotoxicology and
Environmental Safety

Abstract

Iron
plaque (IP) on root surface can enhance the tolerance of plants to
environmental stresses. However, it remains unclear the impact of Fe²⁺ on cadmium (Cd) toxicity to rice (Oryza
sativa) seedlings. In this study, the effects of different Fe²⁺ and Cd²⁺ concentration combinations on rice growth were examined
hydroponically. Results indicated that Fe²⁺ concentration up to
3.2mM did not damage rice roots while induced IP formation obviously. Cd²⁺ of 10 μM repressed rice growth significantly, while the addition of 0.2mM Fe²⁺ to 10 μMCd²⁺ solution (Cd+Fe) did not damage rice roots, indicating
that Fe²⁺ could ameliorate Cd toxicity to rice seedlings. Microstructure
analysis showed Cd+Fe treatment induced the formation of IP with dense and
intricate network structure, Cd adsorption on the root surface was reduced
significantly. Cd concentration of rice roots and shoots and Cd translocation
from roots to shoots with Fe+Cd treatment were reduced by 34.1%, 36.0% and 20.1%,
respectively, in comparison to a single Cd treatment. Noteworthy, the removal
of IP resulted in a larger loss of root biomass under Cd treatment. In
addition, Cd+Fe treatment increased the activities of root superoxide dismutase
and catalase by 105.5% and 177.4%, and decreased H₂O₂ and
O₂·- accumulation of rice roots by 56.9% and 35.9%, and recovered
Cd-triggered electrolyte leakage obviously, when compared with a single Cdtreatment.
The results from this experiment indicated that the formed dense IP on rice
roots decreased Cd absorption and reactive oxygen species accumulation, and
Fe2+ supply alleviated Cd toxicity to rice seedlings.

附件：Root iron plaque alleviates cadmium toxicity to rice ( Oryza sativa ) seedlings