Thermoinhibition of seed germination

Abstract

Thermoinhibition describes the inability of seeds to germinate at high temperatures, although germination proceeds immediately when the temperature is reduced below a certain threshold level. This phenomenon is distinct from thermodormancy, where some form of dormancy-breaking treatment is required before germination can proceed at the favourable temperature. Like seed dormancy, thermoinhibition is manifested in a number of different ways, ranging from simple high-temperature induced changes to the structures enclosing the embryo which prevent radicle emergence, to the interaction of a number of different factors, and probable expression of certain genes inhibitory to germination which may be temperature regulated. Thermoinhibition occurs in a large number of important crop species, so that an understanding of this phenomenon is both of scientific interest and practical importance.