Depending on the applied concentration, nitrate can either stimulate or inhibit germination of dormant seeds of Sinapis arvensis L. (wild mustard). Seed NO− 3 levels that corresponded to the maximal germination frequencies recorded, ranged from 0.3 to 4.4 nmol seed−1 for applied NO− 3 concentrations between 2.5 and 20 mol m−3. Germination was significantly lower in seeds containing more than 5 nmol NO− 3. Although the presence of NO− 3 within the seed was required to promote germination, seed NO− 3 levels were 5 to 15 times less than levels calculated from the volume of solution taken up by the seeds. Seed NO− 3 levels also responded in a passive fashion to the external NO3 − concentration when the seeds were incubated on filter paper or in soil. In a representative soil containing 26 mg NO− 3‐N per kg dry weight and 8 to 16% water by weight, the amount of NO− 3 taken up by the seeds reached inhibitory levels. Our results suggest that levels of inorganic nitrogen (NO− 3, NH+ 4) in managed soils may play an important role in regulating germination of dormant S. arvensis seeds.
|Number of pages||4|
|Journal||Plant, Cell & Environment|
|Publication status||Published - 1 Jan 1988|