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Çakmak, İsmail; Welch, Ross M.; Erenoğlu, B.; Römheld, Volker; Norvell, W. A.; Kochian, Leon V.

doi:10.1023/a:1004777631452

Cited by 65 publications

(12 citation statements)

References 26 publications

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Section: Discussionmentioning

confidence: 99%

“…To be sure, there is evidence for Cd transport via the phloem [35-40], including direct measurement of Cd in phloem sap [27,41,42]. However, extensive evidence documenting low rates of remobilization of Cd from leaves towards growing sink tissues, such as grain, roots, and young expanding leaves [35,36,39,40], suggests that Cd has limited phloem mobility in wheat. As an example, the low- and high-Cd NILs have been shown to differ in 109 Cd transport from the flag leaf to the grain via the phloem [37], but the majority (75-80%) of absorbed 109 Cd was retained in the labelling region; only 10 to 15% of the 109 Cd was transported to the grain after 7 d. In contrast, 65-70% of 65 Zn absorbed by the flag leaf was transported to the grain [37].…”

Section: Discussionmentioning

confidence: 99%

“…As an example, the low- and high-Cd NILs have been shown to differ in 109 Cd transport from the flag leaf to the grain via the phloem [37], but the majority (75-80%) of absorbed 109 Cd was retained in the labelling region; only 10 to 15% of the 109 Cd was transported to the grain after 7 d. In contrast, 65-70% of 65 Zn absorbed by the flag leaf was transported to the grain [37]. Similarly, in seedlings of Triticum species, 109 Cd applied to the mature first leaf was largely (~95%) retained in the labelled leaf; between 1 and 2% of the absorbed 109 Cd was transported to other shoot tissues after 42 h [39,40]. Transport of phloem-mobile 86 Rb to other shoot tissues was 10-fold higher than that of 109 Cd [40].…”

Section: Discussionmentioning

confidence: 99%

“…Similarly, in seedlings of Triticum species, 109 Cd applied to the mature first leaf was largely (~95%) retained in the labelled leaf; between 1 and 2% of the absorbed 109 Cd was transported to other shoot tissues after 42 h [39,40]. Transport of phloem-mobile 86 Rb to other shoot tissues was 10-fold higher than that of 109 Cd [40]. Several other studies have also documented evidence of low rates of remobilization of Cd from leaves [35,36,43].…”

Section: Discussionmentioning

confidence: 99%

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Cadmium uptake and partitioning in durum wheat during grain filling

2013

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BackgroundConcentrations of cadmium (Cd) in the grain of many durum wheats (Triticum turgidum subsp. durum) grown in North American prairie soils often exceed international trade standards. Genotypic differences in root-to-shoot translocation of Cd are a major determinant of intraspecific variation in the accumulation of Cd in grain. We tested the extent to which changes in whole-plant Cd accumulation and the distribution of Cd between tissues influences Cd accumulation in grain by measuring Cd accumulation throughout the grain filling period in two near-isogenic lines (NILs) of durum wheat that differ in grain Cd accumulation.ResultsRoots absorbed Cd and transported it to the shoots throughout the grain filling period, but the low- and high-Cd NILs did not differ in whole-plant Cd uptake. Although the majority of Cd accumulation was retained in the roots, the low- and high-Cd NILs differed substantively in root-to-shoot translocation of Cd. At grain maturity, accumulation of Cd in the shoots was 13% (low-Cd NIL) or 37% (high-Cd NIL) of whole-plant Cd accumulation. Accumulation of Cd in all shoot tissue, including grain, was at least 2-fold greater in the high-Cd NIL at all harvests. There was no net remobilization of shoot Cd pools during grain filling. The timing of Cd accumulation in grain was positively correlated with grain biomass accumulation, and the rate of grain filling peaked between 14 and 28 days post-anthesis, when both NILs accumulated 60% of total grain biomass and 61-66% of total grain Cd content.ConclusionsThese results show that genotypic variation in root-to-shoot translocation of Cd controls accumulation of Cd in durum wheat grain. Continued uptake of Cd by roots and the absence of net remobilization of Cd from leaves during grain filling support a direct pathway of Cd transport from roots to grain via xylem-to-phloem transfer in the stem.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Cadmium uptake and partitioning in durum wheat during grain filling

2013

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“…Radioactive metal isotopes supplied to plants can be detected by autoradiography, both at the whole plant and/or organ level (Cakmak et al, 2000a,b; Erenoglu et al, 2002). The application of 59 Fe-citrate to source tissues of pea plants showed that Fe is complexed prior to phloem loading (Grusak, 1994).…”

Section: Metals In Plant Fluidsmentioning

confidence: 99%

Metal species involved in long distance metal transport in plants

Álvarez‐Fernández¹,

Díaz-Benito²,

Abadı́a³

et al. 2014

Front. Plant Sci.

125

106

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The mechanisms plants use to transport metals from roots to shoots are not completely understood. It has long been proposed that organic molecules participate in metal translocation within the plant. However, until recently the identity of the complexes involved in the long-distance transport of metals could only be inferred by using indirect methods, such as analyzing separately the concentrations of metals and putative ligands and then using in silico chemical speciation software to predict metal species. Molecular biology approaches also have provided a breadth of information about putative metal ligands and metal complexes occurring in plant fluids. The new advances in analytical techniques based on mass spectrometry and the increased use of synchrotron X-ray spectroscopy have allowed for the identification of some metal-ligand species in plant fluids such as the xylem and phloem saps. Also, some proteins present in plant fluids can bind metals and a few studies have explored this possibility. This study reviews the analytical challenges researchers have to face to understand long-distance metal transport in plants as well as the recent advances in the identification of the ligand and metal-ligand complexes in plant fluids.

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Influence of nano‐zinc oxide on tropane alkaloid production, h6h gene transcription and antioxidant enzyme activity in Hyoscyamus reticulatus L. hairy roots

Asl

Hosseini

Sharafi

et al. 2018

Engineering in Life Sciences

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The use of nanotechnology and biotechnology to improve the production of plant bioactive compounds is growing. Hyoscyamus reticulatus L. is a major source of tropane alkaloids with a wide therapeutic use, including treatment of Parkinson's disease and to calm schizoid patients. In the present study, hairy roots were obtained from two‐week‐old cotyledon explants of H. reticulatus L. using the A7 strain of Agrobacterium rhizogenes. The effects of different concentrations of the signaling molecule nano‐zinc oxide (ZnO) (0, 50, 100 and 200 mg/L), with three exposure times (24, 48 and 72 h), on the growth rate, antioxidant enzyme activity, total phenol contents (TPC), tropane alkaloid contents and hyoscyamine‐6‐beta‐hydroxylase (h6h) gene expression levels were investigated. Growth curve analysis revealed a decrease in fresh and dry weight of ZnO‐treated hairy roots compared to the control. ANOVA results showed that the antioxidant activity of the enzymes catalase, guaiacol peroxidase and ascorbate peroxidase was significantly higher in the ZnO‐treated hairy roots than in the control, as was the TPC. The highest levels of hyoscyamine (37%) and scopolamine (37.63%) were obtained in hairy roots treated with 100 mg/L of ZnO after 48 and 72 h, respectively. Semi‐quantitative RT‐PCR analysis revealed the highest h6h gene expression was in hairy roots treated with 100 mg/L of ZnO after 24 h. It can be concluded that ZnO is as an effective elicitor of tropane alkaloids such as hyoscyamine and scopolamine due to its enhancing effect on expression levels of the biosynthetic h6h gene.

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Cited by 65 publications

References 26 publications

Cadmium uptake and partitioning in durum wheat during grain filling

Cadmium uptake and partitioning in durum wheat during grain filling

Metal species involved in long distance metal transport in plants

Influence of nano‐zinc oxide on tropane alkaloid production, h6h gene transcription and antioxidant enzyme activity in Hyoscyamus reticulatus L. hairy roots

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