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ABSTRACT: Aims The efficacy of N,N′-bis(2-hydroxybenzyl)ethyl-enediamine-N,N′-diacetic acid (HBED) as an Fe source in plant nutrition for soybean (Glycine max) plants grown in calcareous soil under controlled con-ditions was studied. Methods The ability of ethylenediamine-N,N′-bis(o-hydroxyphenylacetic) acid (o,oEDDHA/ 57 Fe 3+) and HBED/ 57 Fe 3+ at increasing concentrations and the long lasting effect were evaluated. In addition, iron nutrition was studied considering the Fe uptake from the chelates prepared with the isotope 57 Fe. Further, the SPAD index, total Fe and 57 Fe content in plant were analyzed and soluble and available 57 Fe fractions in soil were deter-mined over time. Results Doses experiment indicated that a higher con-centration of HBED/ 57 Fe 3+ as compared to o,oED-DHA/ 57 Fe 3+ is necessary for obtaining the same 57 Fe absorption by the plant; however, these differences were found to be lower in the second sampling time as com-pared to the first one. This long lasting effect of HBED/ Fe 3+ was corroborated in the long term experiment. Moreover, it was found that the load of Fe in the pods was higher when using HBED/ 57 Fe 3+ than when o,oED-DHA/ 57 Fe 3+ was used. The soil extract analysis for each sampling time indicated that HBED/ 57 Fe 3+ presented a higher stability in soil than o,oEDDHA/ 57 Fe 3+ over time. Conclusion The HBED/Fe 3+ could be a long lasting alternative to EDDHA/Fe 3+ for correcting the iron chlorosis of dicotyledonous plants grown on calcare-ous soils.
Plant and Soil 05/2012; · 2.73 Impact Factor
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ABSTRACT: Iron chlorosis is commonly corrected by the application of EDDHA chelates, whose industrial synthesis produces o,oEDDHA together
with a mixture of regioisomers and other unknown by-products. HJB, an o,oEDDHA analogous, is a new chelating agent with a
purer synthesis pathway than EDDHA. The HJB/Fe3+ stability constant is intermediate between the racemic and meso o,oEDDHA/Fe3+ stereoisomers. This work studied the efficacy of HJB as a Fe source in plant nutrition. No significant differences between
o,oEDDHA/Fe3+, HJB/Fe3+ and HBED/Fe3+ were observed when they are used as substrates of the iron-chelate reductase of mild chlorotic cucumber plants. Chelates
prepared with the stable isotope 57Fe were used in both soil and hydroponic experiments. In the hydroponic experiment, nutrient solutions with low doses of chelates
were renewed weekly. Soybean plants treated with o,oEDDHA/57Fe3+ recorded the highest results in biomass, SPAD index and Fe nutrition. In the soil experiment, chelates were added once at
a rate of 2.5mg Fe per kg of a calcareous soil. Soybean plants treated with HJB/57Fe3+ recorded a higher biomass and SPAD index in young leaves than the plants treated with o,oEDDHA/57Fe3+; however, 57Fe and total Fe concentrations in leaves were lower. The results of both pot experiments are associated with a faster ability
by o,oEDDHA to provide Fe to the plants and with a more continuous supply of Fe from HJB/Fe3+. HJB/57Fe3+ effectively alleviated the Fe-deficiency chlorosis of soybean with a longer lasting effect than o,oEDDHA/57Fe3+.
Plant and Soil 04/2012; 325(1):65-77. · 2.73 Impact Factor
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ABSTRACT: In this study we have obtained experimental evidence that confirms the high activity of aquo complexes III and IV towards the enzyme FCR, responsible for the reduction of Fe(III) to Fe(II) in the process of iron acquisition by plants. The in vivo FCR assays in roots of stressed cucumber plants have shown a higher efficiency of the family of complexes III and a striking structure-activity relationship with the nature of the substituent placed in a phenyl group far away from the metal center. The results obtained in this work demonstrate that all the aquo compounds tested interact efficiently with the enzyme FCR and hence constitute a new concept of iron chelates that could be of great use in agronomy.
Organic & Biomolecular Chemistry 03/2012; 10(11):2272-81. · 3.70 Impact Factor
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ABSTRACT: The synthesis of commercial EDDHA produces o,o-EDDHA as the main reaction product, together with a mixture of regioisomers (o,p-EDDHA and p,p-EDDHA) and other unknown byproducts also able to complex Fe3+. These compounds have been obtained by direct synthesis, and their structures have been determined by ESI-MS analysis as oligomeric EDDHA-like products, formed by polysubstitution in the phenolic rings. Short-term experiments show that the iron complexes of samples enriched in these oligomeric byproducts have adequate stability in solution, but a significant amount of them is lost after interaction with soils and soil materials. Mildly chlorotic cucumber plants are able to reduce iron better from o,p-EDDHA/Fe3+ than from the iron complexes of the oligomeric byproducts. In hydroponics, the chlorotic soybean susceptible plants have a lower potential for Fe absorption from these byproducts than from o,o-EDDHA/Fe3+ and from o,p-EDDHA/Fe3+. In the studied conditions, the iron chelates of EDDHA byproducts do not have the long-lasting effect shown by o,o-EDDHA/Fe3+ and present a less efficient fast-action effect than the o,p-EDDHA/Fe3+.
Journal of Agricultural and Food Chemistry 07/2006; 54(12):4355-63. · 2.82 Impact Factor
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ABSTRACT: The synthesis of commercial EDDHA produces o,o-EDDHA as the main reaction product, together with a mixture of regioisomers (o,p-EDDHA and p,p-EDDHA) and other unknown byproducts also able to complex Fe3+. These compounds have been obtained by direct synthesis, and their structures have been determined by ESI-MS analysis as oligomeric EDDHA-like products, formed by polysubstitution in the phenolic rings. Short-term experiments show that the iron complexes of samples enriched in these oligomeric byproducts have adequate stability in solution, but a significant amount of them is lost after interaction with soils and soil materials. Mildly chlorotic cucumber plants are able to reduce iron better from o,p-EDDHA/Fe3+ than from the iron complexes of the oligomeric byproducts. In hydroponics, the chlorotic soybean susceptible plants have a lower potential for Fe absorption from these byproducts than from o,o-EDDHA/Fe3+ and from o,p-EDDHA/Fe3+. In the studied conditions, the iron chelates of EDDHA byproducts do not have the long-lasting effect shown by o,o-EDDHA/Fe3+ and present a less efficient fast-action effect than the o,p-EDDHA/Fe3+. Keywords: Iron chelates; fertilizers; o,o-EDDHA; o,p-EDDHA
05/2006;
