Abstract
Nitrate reductase activity (NRA) was found in primary roots, but not in foliage of red spruce (Picea rubens Sarg.) seedlings. Nitrate induced NRA:NH4+ did not induce and slightly depressed NRA in older seedlings. Induction required 8 hours and, once induced, NRA decreased slowly in the absence of exogenous NO3−. Seedlings were grown in perlite with a complete nutrient solution containing NH4+ to limit NR induction. Established seedlings were stressed with nutrient solutions at pH 3, 4, or 5 supplemented with Cl− salts of Al, Cd, Pb, or Zn each at two concentrations. NRA in primary root tips was measured at 2, 14, 28, and 42 days. NRA induction was greatest at pH 3, and remained high during the period of study. NRA induction at pH 4 was lower. Metal ions suppressed NRA at pH 3 and 5, but enhanced NRA at pH 4. It is concluded that acidity and soluble metals in the root environment of red spruce are unlikely to be important factors in nitrogen transformations in red spruce roots.
Full text
PDF
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Schrader L. E., Ritenour G. L., Eilrich G. L., Hageman R. H. Some characteristics of nitrate reductase from higher plants. Plant Physiol. 1968 Jun;43(6):930–940. doi: 10.1104/pp.43.6.930. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Streeter J. G., Bosler M. E. Comparison of in vitro and in vivo assays for nitrate reductase in soybean leaves. Plant Physiol. 1972 Mar;49(3):448–450. doi: 10.1104/pp.49.3.448. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Vitousek P. M., Gosz J. R., Grier C. C., Melillo J. M., Reiners W. A., Todd R. L. Nitrate losses from disturbed ecosystems. Science. 1979 May 4;204(4392):469–474. doi: 10.1126/science.204.4392.469. [DOI] [PubMed] [Google Scholar]