postmaturation

Postmaturation is a developmental phase in seeds and other plant propagules that occurs after the organ has reached physiological maturity but before it gains the capacity to germinate or perform its mature function. In seeds, physiological maturity marks the end of major developmental processes, but many species continue to undergo changes during a period of postmaturation that affects dormancy and germination readiness. This phase often involves drying and metabolic adjustments that prepare the seed for desiccation tolerance and future germination.

During postmaturation, seeds undergo hormonal and physiological changes that influence dormancy status. A common pattern is a shift in hormone balance, typically a decline in abscisic acid (ABA) and alterations in gibberellin (GA) signaling, which can lead to the gradual release from dormancy. Metabolic remodeling, changes in storage reserves, and structural modifications of seed tissues also occur, often accompanied by decreasing moisture content as seeds dry during storage. Gene expression patterns shift to support readiness for germination once favorable conditions arise.

The duration and character of postmaturation are highly species- and environment-dependent, varying from days to years and influenced by temperature, humidity, and storage conditions. Its practical significance is substantial in agriculture and horticulture, affecting seed viability, timing of germination, and seed-bank longevity. Management practices such as controlled drying, after-ripening storage, stratification, or priming can manipulate postmaturation to achieve more uniform and reliable germination. While most emphasis is on seeds, similar ideas apply to other plant propagules that undergo maturation-related changes after initial maturity.