Comparative germination of seeds, matured during winter or summer, of some bi-seasonal flowering perennial desert Aiozaceae

Abstract

Shrub species of Aiozaceae were introduced from South Africa to Israel as seeds, and grew in the field for about 5 years at Sede Boker in the Negev Desert Highlands. In the three species of bi-seasonal flowering perennial desert shrubs tested, it was found that seeds matured during winter (under natural short days and low temperatures) and harvested after winter, differed in their ability to germinate from seeds from the same mother plant that matured and were harvested in summer under natural long days and high temperatures. Different rates and levels of germination were also found in the same harvest of seeds, when these imbibed in water at different temperatures in the light, dark or in the dark with brief illumination. The influence of the environmental conditions during winter and summer maturation (which result in the differential ability of the seeds to germinate) is discussed.