Whole shoot mineral partitioning and accumulation in pea (Pisum sativum)

Authors: SANKARAN, RENUKA - City University Of New York; Grusak, Michael

Submitted to: Frontiers in Plant Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/28/2014
Publication Date: 4/23/2014
Citation: Sankaran, R.P., Grusak, M.A. 2014. Whole shoot mineral partitioning and accumulation in pea (Pisum sativum). Frontiers in Plant Science. 5:149.

Interpretive Summary: Plant foods are the principal source of dietary minerals for humans and animals, with seeds of cereals and grain legumes serving as important foods. The amount of minerals in seeds depends on a multi-step process that involves mineral uptake from the soil into the roots, movement into the shoot vegetative tissues, and subsequent movement to the developing seeds. We have been interested in improving the mineral concentration of pea, an important grain legume that serves as a source of nutrients for humans, especially in parts of the developing world. Thus, we have conducted studies to develop a baseline understanding of whole-plant mineral content in pea, as well as mineral distribution throughout the plant over time. This will provide a starting point for future strategies to improve seed mineral concentrations in this crop. For these studies, we grew plants with a complete source of mineral nutrients and harvested plants every week until full maturity. Plants were separated into roots, stems, leaves, pod walls, and seeds. Plant parts were weighed, then digested and analyzed for various minerals. We learned the extent to which individual minerals were distributed between seed and non-seed parts of the plant. This information can now be used to determine how best to move more of a given mineral into the seeds. For some minerals it will require additional uptake from the soil, while for others it might be possible to redistribute more of what is already in the plant.

Technical Abstract: Several grain legumes are staple food crops that are important sources of minerals for humans; 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 mechanism and partitioning of minerals in pea could help in developing cultivars with high mineral density. A mineral partitioning study was conducted in pea to assess whole-plant growth and mineral content and the potential source-sink remobilization of different minerals, especially during seed development. Shoot and root mineral content increased for all the minerals, although tissue-specific partitioning differed between the minerals. Net remobilization was observed for P, S, Cu, and Fe from both the vegetative tissues and pod wall, but the amounts remobilized were much below the total accumulation in the seeds. Within the mature pod, more minerals were partitioned to the seed fraction (>75%) at maturity than to the pod wall for all the minerals except Ca, where only 21% was partitioned to the seed fraction. Although there was evidence for net remobilization of some minerals from different tissues into seeds, continued uptake and translocation of minerals to source tissues during seed fill is as important, if not more important, than remobilization of previously stored minerals.