Recent Perspectives on Synthetic Seed Technology Using NonembryogenicIn Vitro–Derived Explants

Abstract

This article describes recent advances in research on the technology of synthetic seeds, with a particular focus on the potential use of propagules other than somatic embryos. Definitions are proposed to clarify the use of often confusing terms. A classification of the different types of unipolar propagules, according to their origin and nature, is also attempted. The explants could be divided into three groupings: natural unipolar propagules, i.e., microbulbs, microtubers, rhizomes, corms; microcuttings, i.e., shoots and nodes with apical or axillary buds; and differentiating propagules, in vitro–regenerated tissues that have not reached a mature stage, such as meristemoids, cell aggregates, and primordia. For each propagule type, some of the more recent literature about their application to synthetic seed technology is also reviewed, and the problems that still limit their practical use are discussed. Final considerations are made on some specific applications of synthetic seeds that could already be co...