Life-Cycle Analysis of Whole-Plant Mineral Dynamics in Common Bean.

Common bean (Phaseolus vulgaris) is an important staple food crop for population groups throughout the world and is a rich source of mineral nutrients for humans.  Several researchers are interested in improving the nutritional quality of bean seeds, but unfortunately our knowledge is incomplete with respect to the mechanisms of translocation of these minerals to the vegetative tissues and loading into seeds. Understanding the whole-plant dynamics of mineral uptake and partitioning in bean, throughout the plant’s life cycle, could help in developing strategies for breeding cultivars with higher seed mineral density. A mineral partitioning study was conducted to assess whole-plant growth and mineral content in root and shoot tissues using three bean cultivars.  Plants were grown in a perlite-vermiculite medium that allowed easy harvesting of root tissues. A drip line system that delivered a complete nutrient solution three times a day was used to provide nutrients to the plants.  Plants were harvested at two-week intervals and were separated into roots, leaves, stems, and (when available) whole pods.  Tissues were dried, weighed, and processed for mineral analysis.  Data will be presented on the mineral content of various plant parts throughout the life cycle.  The results will be used to discuss the potential for elevating seed mineral concentrations with existing minerals within the plant, versus the need for additional uptake from the soil.  This work was funded in part by the USDA Agricultural Research Service through Cooperative Agreement no. 58-6250-0-008 and the US Agency for International Development through the Feed the Future Grain Legumes Project.