Chemical forms of iron in xylem sap from graminaceous and non-graminaceous plants

Abstract

Graminaceous plants can take up iron-phytosiderophore complexes, whereas non-graminaceous plants absorb ferrous ions after the reduction of ferric compounds at the root cell membranes. The iron (Fe) in the roots may be transported to the aerial plant parts through the xylem. We compared the chemical forms in xylem sap collected from the cut stems of three graminaceous .]) grown in composite soils for the concentrations of iron and iron-chelating compounds (nicotianamine, phytosiderophores, citrate). We also fractionated the xylem saps by size-exclusion chromatography to gain insight into the chemical forms of iron. The Fe concentrations in the xylem sap ranged from 9 to 40 μM. Nicotianamine was found in the xylem sap from all the plants examined, with higher concentrations in the non-graminaceous plants. In contrast, phytosiderophores (2'-deoxymugineic acid and mugineic acid) were predominantly detected in the graminaceous plants. The concentrations of free citrate varied greatly (from 4 to 2200 μM) among the six plant species. The xylem sap iron in non-graminaceous plants may form two types of Fe-citrate, whereas in graminaceous plants, the bound Fe forms may be largely two types of Fe-citrate with various Fe-phytosiderophores.

Concentrations of metals and potential metal‐binding compounds and speciation of Cd, Zn and Cu in phloem and xylem saps from castor bean plants (Ricinus communis) treated with four levels of cadmium

“…As Pich and Scholz (1996) found previously in tomato plants, all the Cu in the xylem sap from the castor bean ( Fig. 4C) was bound to NA, but NA in the xylem sap did not bind other metals such as Fe (Ariga et al 2014) and Cd (Fig. 2B).…”

“…The free citrate concentration in the xylem sap in the control castor bean plants was around 3.4 µ M (Table ), while the Fe concentration in the xylem sap was approximately 10 µ M (Table ). Another study regarding Fe forms in xylem sap from castor bean plants showed that there are two forms of Fe–citrate complex (Ariga et al ). The free citrate concentration in the phloem sap from castor bean plants was around 75–100 µ M (Table ).…”

A Vacuolar Phytosiderophore Transporter Alters Iron and Zinc Accumulation in Polished Rice Grains

“…3), these results suggest that OsVMT mediates the sequestration of DMA to the vacuoles of the root cells, forming the Fe(III)-DMA complex in the vacuoles, followed by exporting this complex from the vacuoles for subsequent translocation of this complex to the xylem. This is supported by the finding that a portion of Fe in the xylem sap is presented in the form of the Fe(III)-DMA complex Ariga et al, 2014). In the mutants, since DMA is not sequestered into the vacuoles, more DMA is loaded to the xylem (Fig.…”

Influence of salinity on transport of Nitrates and Potassium by means of the xylem sap content between roots and shoots in young tomato plants

“…Ferrario et al,1992;Urrestarazu et al, 1996b;Kato et al, 2001;Masuda et al, 2001;Rep et al, 2003;Yamasaki, 2003) and still today (Ariga et al, 2014) for herbaceous plants. For these plants, their daily variations have been studied (e.g.…”