Can genotypes of soybean (Glycine max) selected for nitrate tolerance provide good "models" for studying the mechanism of nitrate inhibition of nitrogenase activity?

1996 ◽  
Vol 98 (3) ◽  
pp. 653-660 ◽  
Author(s):  
Hwee Hwee Neo ◽  
Stephen Hunt ◽  
David B. Layzell
Keyword(s):  
Glycine Max ◽  
Nitrogenase Activity ◽  
Nitrate Tolerance ◽  
Nitrate Inhibition

Nitrogen Fixing Activity in Separated from Plant Cell Cultures

1975 ◽  
Vol 30 (9-10) ◽  
pp. 687-688 ◽  
Author(s):  
D. Werner ◽  
J. Wilcockson ◽  
B. Kalkowski
Keyword(s):  
Glycine Max ◽  
Plant Cell ◽  
Cell Cultures ◽  
Nitrogenase Activity ◽  
Plant Cells ◽  
Plant Cell Cultures ◽  
Rhizobium Japonicum ◽  
Tissue Cultures ◽  
Nitrogen Fixing

Induced by soy bean tissue cultures in socalled “tissue chambers”, Rhizobium japonicum str. 61-A-96 developed nitrogenase activity separated from the plant cells. The activity proceded for 48 h with a rate of 1 × 10-8 nmol C2H4 h-1 cell-1, which is about 6% of the activity measured for bacteroids from Rhizobium japonicum in nodules of Glycine max.

Stomatal conductance, photosynthesis and acetylene reduction rate in soybean genotypes

1992 ◽  
Vol 72 (2) ◽  
pp. 383-390 ◽  
Author(s):  
A. Djekoun ◽  
C. Planchon
Keyword(s):  
Glycine Max ◽  
Water Stress ◽  
Stomatal Conductance ◽  
Acetylene Reduction ◽  
Nitrogenase Activity ◽  
Leaf Water ◽  
Acetylene Reduction Activity ◽  
Reduction Activity ◽  
Leaf Osmotic Potential ◽  
Glycine Max L

Yield limitation in soybean (Glycine max L. Merr.) can result from decreases in photosynthesis and N2 fixation during periods of water deficiency. In this study, the relationships among stomatal conductance, photosynthesis and N2 fixation were analyzed in connection with drought tolerance of genotypes. Plants were grown in pots and exposed to field conditions. Carbon dioxide exchange rate was measured by gas analysis and nodule activity by the acetylene reduction method. Leaf water status was determined with a pressure bomb, and nodule water potential and leaf osmotic potential were measured psychrometrically. The differing tolerances of the cultivars Kingsoy and Hodgson to leaf water deficit resulted in a more or less developed ability of the lower side of the leaf to maintain good stomatal conductance during water stress. Stomatal conductance affects photosynthetic rate directly and acetylene reduction activity indirectly. Early stomatal closure, by limiting H2O exchange, contributes to conservation of nitrogenase activity. On the contrary, maintenance of high conductance during a water stress decreases soil water availability and nodule water content, which in turn has a decisive and limiting effect on acetylene reduction activity. Thus, if tolerance at low leaf water potentials associated with osmotic adjustment is an important drought mechanism for maintaining photosynthetic processes under water-limited conditions, the result would be obtained at the expense of symbiotic N2 fixation.Key words: Glycine max L. Merr., nitrogenase activity, photosynthesis, drought stress, soybean

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