Uptake and preferential partitioning of zinc in different wheat species

Abstract

AbstractSome wild relatives have higher grain zinc (Zn) concentrations than common wheat and were widely used for wheat biofortification. However, little is known about the mechanisms controlling Zn accumulation in wheat and its wild relatives. This study is aimed to shed light on the causes of different grain Zn concentrations in wheat at a physiological level. Six genotypes, including one Triticale, one Triticum monococcum, one Triticum petropavlovskyi, and three Triticum aestivum, with different grain Zn concentrations, were evaluated in this study. Zn concentrations in roots and aboveground tissues in the field at grain maturity were measured to assess the differences in Zn uptake and partitioning among genotypes. Zn concentrations in roots and shoots at the seedling stage in hydroponics were also assessed to see if the differences in Zn uptake efficiencies could be identified before planting in the laboratory. The triticale had the highest grain Zn concentration, followed by the cultivated einkorn wheat, the T. petropavlovskyi wheat, and then the three common wheat varieties. No difference in Zn concentration was detected between grains from the main stem and grains from tillers. Genotypes with high grain Zn concentration generally had higher Zn uptake and rachis Zn loading efficiencies. The cultivated einkorn wheat showed retarded translocation of Zn in nodes. Genotypes with high Zn uptake efficiencies may be identified at the seedling stage in hydroponics. Grain Zn concentration is a product of multiple physiological processes. Roots, nodes, and rachis could be the potential target tissues for further research related to grain Zn accumulation.