Studies on germination ofRumex dentatusL. seeds

The effect of temperature on germination rate ofRumex dentatusadapted to the arid environment of Saudi Arabia was studied. Germination percentage was low (only 20% after 7 days in the dark at laboratory temperature). Cold stratification and gibberellic acid treatment significantly stimulated seed germination. Stratified seeds did not germinate at 35 or 45°C, or at alternating temperatures 28/14 and 36/10°C. Germination was significantly promoted at 15, 18/8 and 21/10°C, and transferring the ungerminated seeds at 25°C and 35°C to 15°C promoted germination. The metabolism of germinated cotyledons was studied at various stages of germination up to 6 days. The analysis of protein by SDS-PAGE showed the appearance of new major and minor bands during germination and only a few components were hydrolysed. Starch content decreased slowly in the first 3 days followed by a period of rapid decline. Amylase activity appeared from the first day and the electrophoretic patterns underwent changes during germination.