Comparative studies of diurnal variations of nitrate reductase ec 1.6.6.1 activity in wheat triticum aestivum cultivar runar oat avena sativa cultivar mustang and barley hordeum vulgare cultivars agneta and gunilla

Lillo, C.; Henriksen, A.

Physiologia Plantarum 62(1): 89-94

1984


ISSN/ISBN: 0031-9317
DOI: 10.1111/j.1399-3054.1984.tb05928.x
Accession: 004998451

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Abstract
Diurnal variations of in vitro and in vivo (intact tissue assay) nitrate reductase (EC 1.6.6.1) activity and stability were examined in leaves of wheat (T. aestivum L. cv. Runar), oat (A. sativa L. cv. Mustang) and barley (H. vulgare L. cv. Agneta and cv. Gunilla). Nitrate reductase activity was generally higher for wheat than for oat and barley. However, the diurnal variations of nitrate reductase activity and stability were principally the same for all species, e.g., the high activity during the photoperiod was associated with low stability. All species showed a rapid (30-60 min) increase in the in vitro and in vivo activity when the light was switched on. When the light was switched off the in vitro activity decreased rapidly whereas the decrease in in vivo activity was slower. These experiments support the hypothesis that an activation/deactivation mechanism is involved in the regulation of diurnal variations in nitrate reductase activity. Red light enhanced nitrate reductase activity in etiolated wheat and barley leaves. In green leaves, however, the daily increase in nitrate reductase activity was not induced by a brief red light treatment. Indications of different regulation mechanisms for the diurnal variations of nitrate reductase activity among the cereals were not found.

Comparative studies of diurnal variations of nitrate reductase ec 1.6.6.1 activity in wheat triticum aestivum cultivar runar oat avena sativa cultivar mustang and barley hordeum vulgare cultivars agneta and gunilla