The influence of imbibition temperature on germination, mitochondria structures, and proteins of winterfat (Ceratoides lanata (Pursh) J. T. Howell)

A series of studies was conducted to gain improved understanding of the relationship between the imbibition temperature and subsequent germination and vigor response of winterfat. Seeds of three winterfat ecotypes, Cheyenne, Pine Bluffs and Sterling were germinated and seedling vigor measured. Imbibition temperature has minimal influence on germination and vigor of seeds less than 1-year-old. Similarly, the benefit to seedling vigor of intact diaspores for fresh seeds (seed with attached bracts) was not evident. These results clarify findings which showed that winterfat seeds increased seedling axil length at low imbibition temperature (0-10{dollar}spcirc{dollar}C). Seeds used in the earlier studies had been stored at 5{dollar}spcirc{dollar}C for 2-3 years. I tested the hypothesis that seed age accounted for the difference between this study and earlier studies. An electron microscope study on seeds from the Cheyenne ecotype showed that during imbibition, the alteration of mitochondrial structure of winterfat radicles occurred more rapidly at 20{dollar}spcirc{dollar}C than at 5{dollar}spcirc{dollar}C in both 1993 and 1986 seeds. Mitochondria of 1993 seeds had more prominent plasma membrane and cristae than mitochondria of 1986 seeds. The normal mitochondrial structure which is typical of hydrated cells was observed in 1993 seeds hydrated to 20% moisture content at 5{dollar}spcirc{dollar}C. Hydration level and the harvest year did not affect the mitochondrial size or number. Hydration of 1993 seeds at 20{dollar}spcirc{dollar}C increased the percentage of total surface area of mitochondria (MA) per unit surface cell area (CA) (MA/CA ratio) as compared to 5{dollar}spcirc{dollar}C.; Protein separation using polyacrylamide gel electrophoresis did not reveal different mitochondrial protein banding patterns, but imbibition temperature and moisture content resulted in different densities of protein bands on the gel.