Gene Expression During Loss and Regaining of Stress Tolerance at Seed Priming and Drying

摘要

Seeds confer a remarkable phase in the life cycle of plants. Most seeds acquire desiccation tolerance during maturation and can be stored for several years without great loss of viability. This phenomenon of stora-bility is diverse among species, among seed lots and even among seeds within a seed lot. In general, storability increases during seed maturation and is gradually lost during seed germination. The latter may create difficulties when seeds are primed. Priming is a process during which seedsare pre-germinated to a certain extent and are re-dried before radicle protrusion to prevent loss of desiccation tolerance. A major advantage of priming is the generally faster and more uniform germination of primed seed, especially under suboptimal conditions. However, this improved germination performance is often accompanied by a reduction in storability, which dictates the need for a careful control of the priming process, in order to avoid progressing the germination process too far. Research performed by Bruggink et al. (1999) showed that the loss of storability could be reduced when the drying was performed slowly or at elevated temperatures. Nothing is known about the underlying mechanisms involved in the gaining of storability during seed maturation, its loss during priming and partial restoration during slow drying. Additionally, very little is known about which processes take place during priming that account for the improved germination performance. For seed companies that perform primingtreatments, it can be of great help if markers are available to support monitoring of the priming process and optimization of the protocol.