ISSN:
1573-5036
Keywords:
Glutamine synthetase
;
Helianthus
;
N utilization
;
Nitrate
;
Nitrate reduction
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Summary It has been reported that in plants of nitrate-fedH. annuus, nitrate reductase activity (NRA) is restricted to the roots of the plant. With an improved extraction technique using a medium containing 2% casein and 1.5 g insoluble polyvinylpyrrolidone (PVP) per gram material, however, the leaves ofH. annuus showed a far greaterin vitro NRA (24.7±0.4 μmoles h−1 g fr.wt.−1) than did the roots (3.4±0.6 μmoles h−1 g fr.wt.−1).In vitro glutamine synthetase activity (GSA) was found to be greater in the leaves (27 μmoles h−1 g fr. wt.−1) than the root (5.6 μmoles h−1 g fr.wt.−1) using a standard extraction medium. With the addition of casein and PVP to the extraction medium, GSA increased to 141 μmoles h−1 g fr.wt.−1 in the leaves and 23 μmoles h−1 g fr.wt.−1 in the roots. It is thus essential to include both casein and PVP in the extracting medium of leaves and roots ofH. annuus when determiningin vitro NRA and GSA.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02182818
Permalink
