Issue |
Agron. Sustain. Dev.
Volume 29, Number 3, July-September 2009
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|
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Page(s) | 483 - 490 | |
DOI | https://doi.org/10.1051/agro/2009008 | |
Published online | 01 July 2009 |
DOI: 10.1051/agro/2009008
Cadmium fate and tolerance in rice cultivars
Jie Zhang1, 2, Wanchun Sun1, Zhaojun Li1, Yongchao Liang1, 3 and Alin Song21 Ministry of Agriculture Key Laboratory of Crop Nutrition and Fertilization, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, P.R. China
2 College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, P.R. China
3 Key Laboratory of Oasis Eco-Agriculture, College of Agriculture, Shihezi University, Shihezi, Xinjiang 832003, P.R. China
Accepted 30 January 2009 ; published online 1 July 2009
Abstract - Cadmium (Cd) is present in all soils, usually as a trace
constituent, but it can reach higher levels in agricultural soils. Cd can
then be absorbed by plants and become a potential risk to human health. Once
taken up by a plant, there are mechanisms for heavy metal detoxification in
the plant. Here, a cadmium-tolerant and a cadmium-sensitive rice cultivars
were grown hydroponically to investigate the effects of cadmium (Cd) applied
at low levels on uptake and transport, subcellular distribution and binding
forms of Cd in rice plants. Our results showed that increasing the Cd
treatment from 1.0 M to 5.0
M Cd increased the shoot Cd content
by 55% in the cadmium-tolerant cultivar, and by 108% in the
cadmium-sensitive cultivar. For the cadmium-tolerant cultivar, increasing Cd
treatment from 1.0
M to 5.0
M increased the root Cd content by 116%, whereas for the cadmium-sensitive cultivar,
increasing Cd treatment
from 1.0
M to 5.0
M increased the root Cd content by 80%.
Further, the ratio of Cd accumulation in shoots over roots decreased from
0.19 to 0.14 in the cadmium-tolerant cultivar, while it increased from 0.20
to 0.26 in the cadmium-sensitive cultivar, showing that the transportation
ability for Cd was different between the two tested rice cultivars. At the
higher Cd level of 5.0
M, most of the Cd in the plants was localized
in cell walls and vacuoles in both cultivars, whereas small portions of Cd
were distributed in the cytoplasm, suggesting that the important metabolic
and physiological processes were not impaired under Cd stress. Furthermore,
the major portions of Cd in the cells were combined with organic acids,
proteins and polysaccharide, and were consequently detoxified. The
difference in the distribution of cadmium in rice plants resulted in the
difference in Cd tolerance between the two rice cultivars used. It can be
concluded that the retention of Cd in root cell walls, compartmentation of
Cd into vacuoles and the suppressed transportation of Cd from roots to
shoots are the most important mechanisms involved in the detoxification of
Cd in rice plants.
Key words: cadmium / rice / subcellular distribution / binding form
Corresponding author: ycliang@caas.ac.cn
© INRA, EDP Sciences 2009