scholarly journals Interaction of Combined Nitrogen with the Expression of Root-Associated Nitrogenase Activity in Grasses and with the Development of N2 Fixation in Soybean (Glycine max L. Merr.)

1983 ◽  
Vol 72 (3) ◽  
pp. 741-745 ◽  
Author(s):  
Peter van Berkum ◽  
Charles Sloger
Keyword(s):  
Glycine Max ◽  
N2 Fixation ◽  
Nitrogenase Activity ◽  
Combined Nitrogen ◽  
Glycine Max L

Differences in photosynthetic behaviour and leaf senescence of soybean (Glycine max [L.] Merrill) dependent on N2 fixation or nitrate supply

Plant Biology ◽  
2010 ◽  
Vol 12 (1) ◽  
pp. 60-69 ◽  
Author(s):  
G. Kaschuk ◽  
M. Hungria ◽  
P. A. Leffelaar ◽  
K. E. Giller ◽  
T. W. Kuyper
Keyword(s):  
Glycine Max ◽  
Leaf Senescence ◽  
N2 Fixation ◽  
Glycine Max L ◽  
Nitrate Supply

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

Effect of Oxygen Supply on Nitrogenase Activity of Nitrate- and Dark-Stressed Soybean (Glycine max (L.) Merr.) Plants

1987 ◽  
Vol 14 (6) ◽  
pp. 679 ◽  
Author(s):  
BJ Carroll ◽  
AP Hansen ◽  
DL Mcneil ◽  
PM Gresshoff
Keyword(s):  
Glycine Max ◽  
Nitrogenase Activity ◽  
Root Nodules ◽  
Short Term ◽  
Glycine Max L ◽  
Autonomous Activity ◽  
Effect Of Oxygen ◽  
Substrate Deprivation ◽  
Dark Stress ◽  
Oxygen Concentrations

Nitrate and dark stress were used to induce decline in nitrogenase activity of root nodules of soybeans (Glycine max (L.) Merr. cv. Bragg). Response to this treatment and to various oxygen concentrations was assessed by short-term acetylene reduction assays. Decreases in oxygen partial pressure reduced nitrogenase activity substantially in unstressed soybean nodules and even further in nodules of nitrate- or dark-stressed plants. Increasing oxygen concentrations from 21 to 60% severely restricted nitrogenase activity in control plants, but stimulated activity in soybeans exposed to 10 mol m-3 nitrate or darkness for 2 days. Less stressed plants (treated with 7.5 mol m-3 nitrate) were stimulated less by high oxygen tension. Soybeans deprived of light for 4 days were symbiotically inactive and did not respond to raised O2 concentrations. Bacteroids isolated from these plants had lost their autonomous activity but recovered in the presence of succinate, indicating substrate deprivation. The data presented suggest that suboptimal oxygen concentration near the bacteroids is an important factor limiting nitrogenase activity in nitrate-or dark-stressed soybeans.

Sign in / Sign up

Export Citation Format

Share Document