When considering germination and dormancy it is essential, especially given the nature of this experiment, to fully understand the effect temperature has on germination. Studies involving buried seeds have shown that temperature during burial plays a dominant role in the regulation of seed dormancy patterns. Changes in dormancy reflect the size of the temperature range at which germination can occur at particular times. In general the, the range is widened during alleviation of dormancy and narrowed during dormancy induction (Vegis 1964, Bouwmeester et al 1992). Thus, temperature controls both changes in dormancy and the actual germination process. The nature of the endogenous changes that are induced in seeds by temperature during burial remain obscure.
The abundant quantities of hormones in seeds at certain stages of development and the effects evoked by exogenous growth on dormancy and germination led to the theory that dormancy is regulated by a balance of simultaneously operating promoters and inhibitors of germination (Amen 1968). In the absence of dormancy, germination responses to temperature can be characterised by Cardinal temperatures, i.e. the optimum temperature, the minimum temperature and the maximum temperature. As the names suggest the minimum temperature is the lowest temperature at which germination will occur, where as the maximum temperature is the highest temperature at which the seed will germinate. In between the optimum and the minimum temperature, temperature primarily influences the rate of germination.
Changes in dormancy reflect themselves in the size of the temperature range at which, germination can proceed at particular times. In general the range is widened during alleviation of dormancy and narrowed during dormancy induction. Thus temperature controls both changes in dormancy and the actual germination process ( Karssen 1982; Bouwmeester and Karssen 1992)
Abstract,Introduction,Germination,Dormancy,Temperature,Light,Ecotypes
Ecotype-Storage,Soil preperation,Seed Sowing,Germination-Conditions,Measurement of Results
Cond1,Cond1rep,Cond2,Cond3,Cond4,Cond5,Cond6,Cond6rep,Cond7,Cond8