Studying the Ecology of Seed Germination and Seedling Emergence of Curly dock (Rumex crispus L.) and Cone Catchfly (Silene conoidea L.)

(Rumex crispus) and cone catchfly (Silene conoidea), experiments were conducted based on RCBD with 3 replications at Research Laboratory of Faculty of Agriculture, Birjand University during autumn 2009 and winter 2010. Experimental treatments were light (Light/Dark and continuous dark), alternating day/night temperatures (10/5, 20/10, 25/15, 30/20 and 35/25 C), salinity stress (0 (Control), 10, 20, 40, 80, 160, 320 and 640 mM), drought stress (0 (Control), -0.1, -0.2, -0.4, -0.6, -0.8 and -1 MPa), pH (4 to 10) and sowing depth (0 to 4 cm). Results showed that seed germination of Curly dock was unaffected by either light/dark or continuous darkness conditions. Greater than 85% of curly duck seeds germinated over a broad range of alternating day/night tested temperatures under light/dark and continuous dark regimes and its germination completely ceased at 10/5 C. Cone catchfly seeds germinated greater than 70% at alternating temperature regimes equal to or lower than 25/15 C under light/dark and continuous dark regimes, but its germinability was remarkably reduced at temperature regimes warmer than 25/15 C, especially under light/dark conditions. Curly dock and Cone catchfly seeds germinated greater than 85% until the salinity level of 160 mM (NaCl), while their germination percentage at osmotic potential of -0.8 MPa were 60 and 90%, respectively. The average germinability of curly dock and cone catchfly seeds over a pH range of 4 to 10 was 90%. Seed burial significantly reduced curly dock and cone catchfly seedling emergence, so that no seedling emerged from a soil depth deeper than 3 cm and the greatest seedling emergence of curly dock and cone catchfly (98 and 74.7%, respectively) was occurred for seeds placed on the soil surface under 3 layers of filter paper.