Distribution and Transport of Zinc in Plants

Abstract

1. Abstract Zinc (Zn) distribution and transport in plants is affected by the level of Zn supply and plant species. When plants have low to adequate Zn supply, Zn concentrations are usually higher in growing tissue than in mature tissue; this is true for roots, vegetative shoots and reproductive tissues. In plants tolerant of toxic levels of Zn, accumulation has been observed in the root cortex and in leaves. In these tissues, Zn accumulates in cell walls or is sequestered in vacuoles. Zinc transport in the xylem does not necessarily coincide with that of water. Zinc is a nutrient with variable mobility that is retranslocated to a greater extent when in adequate supply. Zinc movement out of old leaves coincides with their senescence; both can be delayed by Zn deficiency. Species differ widely in their ability to load Zn into seeds; some native plants adapted to nutrient-poor soils have 10 times greater Zn concentrations in their seeds than most cultivated species, but have similar or lower Zn concentrations in their leaves. 2.