Silicon Enhances the Biosynthesis of Organic Acids in Zinc-deficient Rice

Zinc (Zn), an essential micronutrient for crops, is involved in a variety of physiological processes. The Zn deficiency mainly affects generative growth and seed development and being a component of the antioxidant machinery (e.g., Cu/Zn-SOD) is conductive to oxidative stress in plant tissues. Rice is a typical silicon (Si)-accumulating species, which is strongly affected by Zn deficiency in the alkaline, low Zn soils, especially high in phosphate and/or organic matter. Yet, little is known about the interaction between Si and Zn in rice plants under Zn-deficient conditions. We investigated the effect of Si nutrition on Zn tissue distribution and biosynthesis of organic acid in rice plants subjected to short-term (up to 7 days) and long-term (28 days) Zn deficiency. Tissue concentrations of organic acids by HPLC in parallel Zn and Si by ICP-OES were measured. The Si addition to the nutrient solution successfully mitigated visual symptoms of Zn-deficiency stress and significantly increased dry biomass of rice plants. Interestingly, during the short-term experiment, +Zn plants supplied with Si showed significantly lower Zn concentration in the shoots, but significantly higher Zn concentration in the roots. Also, in the -Zn plants supplied with Si, the concentration of Zn in root tissue rapidly decreased to the level of -Si/-Zn plants, which was followed by an increased concentrations of both organic acids and Zn in the shoots. In the long-term experiment, however, Si did not affect Zn concentration in roots nor in shoots of -Zn plants, but Si differently affected organic acid profile and their tissue accumulation depending on the plant organ and Zn status. In conclusion, Si supply enhanced root-to-shoot translocation of Zn mediated by organic acid ligands during the first 7 days of Zn deficiency

Determinacion de quelatos ferricos de uso agricola. Aplicacion al estudio de su absorcion por materiales edaficos

Centro de Informacion y Documentacion Cientifica (CINDOC). C/Joaquin Costa, 22. 28002 Madrid. SPAIN / CINDOC - Centro de Informaciòn y Documentaciòn CientìficaSIGLEESSpai

Determinacion de quelatos ferricos de uso agricola Aplicacion al estudio de su adsorcion por materiales edaficos

Centro de Informacion y Documentacion Cientifica (CINDOC). C/Joaquin Costa, 22. 28002 Madrid. SPAIN / CINDOC - Centro de Informaciòn y Documentaciòn CientìficaSIGLEESSpai

Gradient ion-pair chromatographic method for the determination of iron N,N '-ethylenediamine-di-(2-hydroxy-5-sulfophenylacetate) by high performance liquid chromatography-atmospheric pressure ionization electrospray mass spectrometry

The most effective remedy for iron deficiency is the use of synthetic iron chelates, specifically chelates derived from polyamine-carboxylic acids as EDDHSA (N,N'-ethylenediamine-di-(2-hidroxy-5-sulfophenylacetic) acid). A gradient ion-pair chromatographic method was developed to quantify the total amount of chelated iron in EDDHSA/Fe-3divided by fertilizers. Two mobile phases were used containing. respectively, 35 and 75% acetonitrile in a 0.005 M tetrabutylammonium hydroxide aqueous solution at pH 6.0. The stationary phase was a reverse phase C-18 column (150 mm x 3.9 mm i.d., dp = 5 mum). Two chromatographic peaks appeared and were identified by Electrospray Mass Spectrometry. The first peak corresponds to the monomer of EDDHSA/Fe-3divided by and the second peak has been assigned to condensation molecules. Quality parameters indicate that the method is suitable for the quantification of iron chelate by EDDHSA fertilizers