Studies on the Relationship between Iron and Cadmium Stress of Rice Seedlings
Date Issued
2011
Date
2011
Author(s)
Chang, Yi-Chu
Abstract
Abstract
In this thesis, rice (Oryza sativa L. cv. Taichung Native 1, TN1) seedlings were used to investigate (a) the effect of iron deficiency on cadmium (Cd) uptake and (b) whether Cd toxicity was resulted from reduction of iron concentration.
Iron deficiency resulted in increasing NO production, OsIRT1 expression, and Cd concentration in rice roots. Iron deficiency induced NO production, OsIRT1 expression and Cd accumulation could be blocked by NO scavenger cPTIO, NOS inhibitor L-NAME, but not NR inhibitor Tu. Collective, our results suggested that iron deficiency induced Cd accumulation and OsIRT1 expression are mediated through NOS-catalyzed NO production in rice roots.
Application of 5 µM CdCl2 to rice seedlings resulted in decreasing iron concentration in shoots and roots, and induced OsIRT1 expression. These results suggested that Cd-treated rice seedlings were in iron starved status. In this thesis, Cd toxicity was judged by the decrease in biomass production, chlorosis, drcrease in chlorophyll content, induction of oxidative stress, and accumulation of ammonia ion. On the basis of these confidences, we demonstrated that application of 10 µM Fe-citrate reduced toxicity of rice seedlings caused by 5 µM CdCl2. Moreover, we also observed Fe-citrate application decreased Cd concentration in shoots and roots. According to our results, the decrease in iron concentration in rice seedlings may contribute to the toxicity caused by CdCl2.
Subjects
cadmium
iron deficiency
nitric oxide
rice seedlings
Type
thesis
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