We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
In vivo nitrate reductase activities in different organs of lucerne (Medicago sativa) plants: Effects of combined nitrogen during first vegetative growth and after shoot harvest.
- Authors
Deroche, Marie-Esther; Babalar, Mesbah
- Abstract
Nitrate reductase (EC 1.6.6.1-3; NR) activity was evaluated in nodulated lucerne (Medicago sativa L. cv. Europe) grown aeroponically in both the presence and absence of applied nitrogen. Determination of in vivo NR activity was done with organ pieces in 0.1 M K+-phosphate, pH 7.5, 0.1 M KNO3 and 1% n-propanol. NR activity was detected in all plant parts. Leaves accounted for 40% of the whole plant activity. Root activity was as high as leaf activity. Stem NR activity accounted for 14 to 20% of the total plant activity. NR activity was also detected in symbiotically dependent plants grown without combined nitrogen. Nodule NR in symbiotically dependent plants accounted for 17% of the total plant activity. When nitrate was present in the nutrient medium, NR increased 5-fold as compared to N2-dependent plants. Varying levels of nitrate (1.65 to 4 mM) had no influence on leaf or stem activities. However, root NR activity seemed to be related to the nitrate concentration in the nutrient medium. Throughout initial vegetative growth, in vivo NR and nitrogenase (acetylene reduction) increased simultaneously. After shoot harvest, nitrogenase (acetylene reduction) activity drastically decreased with reduction of photosynthate supply, whereas NR increased in all organs, especially in N2-dependent plants.
- Subjects
LUCERNE flea; NITROGEN; HARVESTING; BIOCHEMISTRY; SYMBIOSIS; SYMBIOGENESIS
- Publication
Physiologia Plantarum, 1987, Vol 70, Issue 1, p90
- ISSN
0031-9317
- Publication type
Article
- DOI
10.1111/j.1399-3054.1987.tb08702.x