Abstract
The effect of temperature on germination rate of Rumex dentatus adapted 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 degrees C, or at alternating temperatures 28/14 and 36/10 degrees C. Germination was significantly promoted at 15, 18/8 and 21/10 degrees C, and transferring the ungerminated seeds at 25 degrees C and 35 degrees C to 15 degrees 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. (C) 1996 Academic Press Limited