Effect of day length during plant development and caryopsis maturation on flowering and germination, in addition to temperature during dry storage and light during wetting, ofSchismus arabicus(Poaceae) in the Negev Desert, Israel

Schismus arabicusis a common annual with an ‘escape’ strategy of caryopsis dispersal and ‘opportunistic’ strategy of germination. It inhabits the Negev and Saharo-Arabian and Irano-Turanian phytogeographical regions. It displays a quantitative long-day response for flowering and a day length response in caryopses germinability. Germination in the dark was much higher than in light. The longer the period of light, from 0•5 h to continuous light, the lower the percentage of germination. The low percentage of germination, which is also regulated by temperature during dry storage, is important for the survival ofS. arabicusunder the unpredictable distribution and small amounts of rain in its extreme desert habitats.