Fresh and Dry Weight Changes and Germination Capacity of Natural or Premature Desiccated Developing Wheat Seeds

Throughout the course of development wheat seeds undergo changes in both fresh and dry weight and in moisture content. Between 10 and 20 DAF, both fresh and dry weights increase very rapidly. Accumulation of dry matter ceases at the same time as the seed dried out at 40 DAF. The natural desiccation period for wheat seeds is established between 30 and 40 DAF. Freshly harvested wheat seeds are capable of germinating during the period between 20 and 30 DAF but germinating capacity is very low. Increased frequency of germination along with the increase in seed age was observed in case of artificially desiccated seeds. It is noteworthy that the capacity of desiccated seeds to germinate does not depend on the degree of desiccation but only on their age at harvest time.

The amount of water absorbed by desiccated seeds during germination depends on developmental stage of seeds at harvest time. It was established that to the lower initial moisture content of desiccated seeds correspond higher amounts of water absorbed in the course of germination. Moreover for every investigated phase of seed development there is a determined degree of moisture and the water uptake of desiccated seeds can not overcome this value. Full maturity of field grown wheat seeds was reached at 50 DAF.