Russian thistle and barbwire Russian thistle seed and seedbed ecology.
Seed germination and seedbed ecology of (a) Salsola iberica and (b) S. paulsenii were studied. Both spp. exhibited a temp. related afterripening requirement after maturity in autumn and winter. Once this was satisfied both spp. germinated well at a wide range of temp. Seeds of (a) but not (b) germinated well under very low osmotic potentials; lower germination resulted with NaCl than with polyethylene glycol used to lower the osmotic potential. Seedling establishment was increased by soil and litter coverage and by favourable microtopography of the soil surface. Specific adaptations of (b) compared with (a) were earlier maturation and seed dispersal, seed dispersal under parent plants and less specific temp. related afterripening requirements. Even with these characteristics, establishment of (b) was low in arid environments compared with (a).