Canopy and seasonal profiles of nitrate reductase in soybeans
Nitrate reductase activity of soybeans (Glycine max L. Merr.) was evaluated in soil plots and outdoor hydroponic gravel culture systems throughout the growing season. Nitrate reductase profiles within the plant canopy were also established. Mean activity per gram fresh weight per hour of the entire plant canopy was highest in the seedling stage while total activity (activity per gram fresh weight per hour times the total leaf weight) reached a maximum when plants were in the full bloom to midpod fill stage. Nitrate reductase activity per gram fresh weight per hour was highest in the uppermost leaf just prior to full expansion and declined with leaf positions lower in the canopy. Total nitrate reductase activity per leaf was also highest in the uppermost fully expanded leaf during early growth stages. Maximum total activity shifted to leaf positions lower in the plant canopy with later growth stages. Nitrate reductase activity of soybeans grown in hydroponic systems was significantly higher than activity of adjacent soil grown plants at later growth stages, which suggested that under normal field conditions the potential for nitrate utilization may not be realized. Nitrate reductase activity per gram fresh weight per hour and nitrate content were positively correlated over the growing season with plants grown in either soil or solution culture. Computations based upon the nitrate reductase assay of plants grown in hydroponics indicated that from 1.7 to 1.8 grams N could have been supplied to the plant via the nitrate reductase process. 11 references, 9 figures, 3 tables.
- Research Organization:
- Dept. of Agriculture, Urbana, IL
- OSTI ID:
- 6389710
- Journal Information:
- Plant Physiol.; (United States), Vol. 49
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
NITROGEN
METABOLISM
OXIDOREDUCTASES
ENZYME ACTIVITY
CANOPIES
EXPERIMENTAL DATA
GLYCINE HISPIDA
NITROGEN CYCLE
NITROGEN FIXATION
SEASONAL VARIATIONS
BACTERIA
DATA
ELEMENTS
ENZYMES
INFORMATION
LEGUMINOSAE
MICROORGANISMS
NONMETALS
NUMERICAL DATA
PLANTS
RHIZOBIUM
VARIATIONS
550500* - Metabolism