Minimal information exists on whole-plant dynamics of mineral flow through Arabidopsis thaliana or on the source tissues responsible for mineral export to developing seeds. Understanding these phenomena in a model plant could help in the development of nutritionally enhanced crop cultivars.
A whole-plant partitioning study, using sequential harvests, was conducted to characterize growth and mineral concentrations and contents of rosettes, cauline leaves, stems, immature fruit, mature fruit hulls, and seeds of three WT lines (Col-0, Ler, and Cvi) and one mutant line (Col-0::ysl1ysl3).
Shoot mineral content increased throughout the life cycle for all minerals, although tissue-specific mineral partitioning differed between genotypes. In particular, iron (Fe), zinc (Zn), and copper (Cu) were aberrantly distributed in ysl1ysl3. Remobilization was observed for several minerals from various tissues, including cauline leaves and silique hulls, but the amounts were generally far below the total mineral accretion observed in seeds.
When YSL1 and YSL3 are nonfunctional, Cu, Fe, and Zn are not effectively remobilized from, or do not effectively pass through, leaf and maternal fruit tissues. With respect to seed mineral accretion in Arabidopsis, continued uptake and translocation of minerals to source tissues during seed fill are as important, if not more important, than remobilization of previously stored minerals.
New Phytologist (2008) 177 (2) 389-405 [doi: 10.1111/j.1469-8137.2007.02288.x]