Metal species involved in long distance metal transport in plants

Abstract

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.

Cadmium effects on mineral accumulation, antioxidant defence system and gas exchange in cucumber

“…When taken up by plants, cadmium may cause several physiological, biochemical and structural changes (Benavides et al, 2005). Cadmium has been shown to interfere with the uptake, transport and use of several elements (Álvarez-Fernández, 2014;Sperotto et al, 2014). Cadmium has been shown to be one of the most effective inhibitors of photosynthetic activity.…”

Stability of the Inherent Target Metallome in Seed Crops and a Mushroom Grown on Soils of Extreme Mineral Spans

“…They are then unloaded into the xylem as free cations or recomplexed with common ligands such as carboxylates, NA, histidine, and phytochelatins in dicots; with carboxylates and 2'-desoxymugineic acid in monocots; or as arsenite > arsenate and selenate metalloids, respectively (for reviews, e.g., [50][51][52]). At the base of cereal grains, the xylem transport is discontinuous [53].…”

“…At the base of cereal grains, the xylem transport is discontinuous [53]. The minerals therefore pass over, after further putative recomplexations [50], at peduncle and rachis of cereals into the phloem [54,55] to supply sink tissues of the shoot, leaves, and seeds. In the seed coat of the wheat grain, aleurone cells form a layer of the three to four cells highest in the content of FeZn [56], contact the starchy endosperm, and catalyze the mobilization of the storage polymers enzymatically upon germination [57].…”

Xylem sap mineral analyses as a rapid method for estimation plant-availability of Fe, Zn and Mn in carbonate soils: a case study in cucumber

“…Recently, methods for xylem sap sampling and determination of micronutrient species involved in long distance translocation have been successfully reviewed (Alexou and Peuke, 2013;Álvarez-Fernández et al, 2014). However, information on the relevance of xylem sap analysis to evaluate Fe, Zn and Mn plant-availability affected by CaCO 3 levels is still lacking, partly due to the fact that methods of evaluating nutrient availability in soils using xylem sap have so far mainly been applied under conditions in which CaCO 3 was not present.…”