Experimental Studies on the Seed Germination Characteristics of Sedum japonicum and Sedum mexicanum

Abstract

Characteristics found in the seed germination of Sedum japonicum and Sedum mexicanum were examined. Especially, the effects of the differences in the germination temperature, the storage temperature, and the storage period on the seed germination were looked into. The seeds of Sedum japonicum and Sedum mexicanum were collected on 7/13/2001 and 6/10/2000 respectively in advance of this experiment. The first experiment right after the seeds collection was conducted in a Biotron whose temperature was artificially controlled, with the temperature controlled at 10, 15, 20, 25, and 30 degree Celsius. The next experiment was conducted with the seeds whose storage temperature and storage period differed, in the rooms with their temperatures controlled at 10 degree and 25 degree. As a result, it was found that the germination was best promoted between 15 and 20 for Sedum japonicum and between 10 and 15 for Sedum mexicanum. The lowest germination rate was recorded after one month of the collection. In the experiment conducted after this, it was found that the germination characteristics changed as the length of the storage period was prolonged and that the germination of the stored seeds was promoted around 25 degree rather than at the lower temperature. Furthermore both types of the seeds soon failed to germinate when they were stored at the normal temperate and humidity. On the other hand, at the lowered temperature and humidity (at 5 degree of the temperature and 30% of the humidity), the seeds can germinate even after 4 years storage.