Title: Genotypic Difference of Germination and Early Seedling Growth in Response to Cd Stress and its Relation to Cd Accumulation
Abstract: ABSTRACT ABSTRACT A greenhouse experiment was conducted using twelve Japonica rice genotypes differing in grain Cd concentration, to study the genotypic difference in germination and early seedling growth in response to Cd stress and its relation to Cd accumulation. The results showed that under low Cd level (0.5 mM), germination was significantly enhanced for most rice genotypes, but higher Cd levels (2.5 and 10.0 mM) inhibited germination dramatically. When exposed to 10.0 mM Cd, a few genotypes could still germinate, but the seedlings of all genotypes would die in early stage. Shoot height and dry weight, and root length and dry weight of seedling were significantly inhibited at 0.5 and 2.5 mM Cd levels, irrespectively of genotypes, and the inhibition became more severe under higher Cd level. There was a significant genotypic difference in response of germination, early seedling growth and shoot Cd concentration to Cd stress. The difference was the largest for germination, followed by root growth, the least for shoot growth. A cluster analysis of tolerance indices, including germination rate, shoot height and weight, root length and weight of the plants exposed to 2.5 mM Cd level showed that 12 rice genotypes may be grouped into three clusters, i.e. high-, intermediate- and weak Cd-tolerance. No significant correlation was found between grain Cd concentration and Cd-tolerance in terms of germination and seedling growth, and shoot Cd concentrations, suggesting that it is possible to develop rice cultivars with high Cd-tolerance and low grain Cd accumulation. Keywords: CdCd accumulationCd-toleranceEarly seedling growthGenotypic variationGerminationRice (Oryza sativa L.) ACKNOWLEDGEMENTS We are deeply grateful of China Postdoctoral Science Foundation (2005037824), Science and Technology Department of Zhejiang (2005C32007), Science and Technology Bureau of Jiaxing, Zhejiang, China (2005AZ3003 and 2006AZ1008-1) for financial support. We also acknowledge Dr. Yongguan Zhu at the Eco-Environmental Sciences, Chinese Academy of Sciences for his kind helps in analysis and paper revision.
Publication Year: 2008
Publication Date: 2008-04-07
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 18
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