Effects of time of seed maturation on dormancy and germination requirements of Sporobolus spicatus (Vahl) Kunth, a native desert grass of the United Arab Emirates

The effect of time of seed maturation on dormancy and germination requirements was determined for seeds of Sporobolus spicatus (Vahl) Kunth, a species that could be used in rehabilitation of the degraded salt‐affected habitats. Seeds of S. spicatus were collected in May, August and December 2005 and March 2006 from a population around Al‐Ain City, United Arab Emirates (UAE). Seeds were germinated in incubators adjusted at 20°C, 25°C, 30°C and 35°C in continuous light and in darkness. Seeds incubated at the highest temperature (35°C) germinated significantly greater and faster, compared to those at the lower temperatures. The highest germination percentage in S. spicatus was observed for seeds matured during August, followed by those matured in December and May, but the lowest germination was recorded for seeds of March. Seeds of August germinated significantly greater in dark than in light, but the reverse was true for seeds of May. Germination rate was significantly faster for seeds of December than that of other seed lots, even at the lower temperature. The results are discussed in the light of the adaptive significance of the production of tiny seeds at different times of the year in S. spicatus.