Isotopic Discriminations During the Accumulation of Nitrogen by Soybeans

1988 ◽  
Vol 15 (3) ◽  
pp. 407 ◽  
Author(s):  
FJ Bergersen ◽  
MB Peoples ◽  
GL Turner
Keyword(s):  
N2 Fixation ◽  
Root Nodules ◽  
Xylem Sap ◽  
Vacuum Treatment ◽  
Natural Abundance ◽  
Mineral Nutrient ◽  
Similar Time ◽  
Total N ◽  
Plant Nitrogen ◽  
Nitrate Treatment

Soybeans were grown in a glasshouse in sand-vermiculite medium supplied daily with a mineral nutrient solution essentially free of combined N or containing 5 mM nitrate of known 15N abundance. The natural abundance of 15N in parts of plants and in nitrogen remaining in the medium was determined from 15 days after planting until fruiting. In nodulated plants completely dependent on N2 fixation for growth, the δ15N of plant nitrogen was uniformly negative at 56 days (overall mean: -0.90� 0.17) after adjustment for the effect of seed nitrogen. The δ15N of root nodules increased with time (max. 9.6‰), as that of shoots declined (min. - 1.3 ‰). The δ15N of every mainstem trifoliolate leaf and of the first (unifoliolate) leaf declined from initially positive values (0.5 to 2 ‰) to about - 2‰ with similar time courses, irrespective of the time of initiation. There were no significant losses of N from the plants during growth. There were differences between the δ15N of the total N of root-bleeding xylem sap and of sap extracted by vacuum treatment of stems. These were due to differences between the proportions of ureide-N and amino-N and between the δ15N values of these components. When nodulated plants were supplied daily with 5 mM nitrate (δ15N = 7.68‰) between 21 and 35 days, N2 fixation was reduced to 63% of N assimilated but growth and accumulation of nitrogen were affected little. Following removal of nitrate, there were changes in growth which led to enhanced nodulation and N2 fixation. The δ15N of the total N of trifoliolate leaves which were initiated or expanded before or during the period of nitrate treatment remained positive; those expanded or initiated after the treatment became negative in δ15N, as in the corresponding leaves of untreated nodulated plants. The δ15N of nodules was unaffected by the nitrate treatment. In plants (non-nod. Clark '63) supplied continuously with nitrate, the δ15N of the total N of entire plants rose quickly from values for seeds, but to values significantly higher than in the nitrate. These results are discussed in relation to the effects on the use of 15N natural abundance data for estimating utilisation of atmospheric N2 by nodulated plants.

scholarly journals Application of Nitrate, Ammonium, or Urea Changes the Concentrations of Ureides, Urea, Amino Acids and Other Metabolites in Xylem Sap and in the Organs of Soybean Plants (Glycine max (L.) Merr.)

2021 ◽  
Vol 22 (9) ◽  
pp. 4573
Author(s):  
Yuki Ono ◽  
Masashige Fukasawa ◽  
Kuni Sueyoshi ◽  
Norikuni Ohtake ◽  
Takashi Sato ◽  
...  
Keyword(s):  
Glycine Max ◽  
Root Nodules ◽  
Xylem Sap ◽  
Nitrate Treatment ◽  
First Finding ◽  
Metabolite Concentrations ◽  
Glycine Max L ◽  
Soybean Plants ◽  
Positive Correlations ◽  
Ureide Degradation

Soybean (Glycine max (L.) Merr.) plants form root nodules and fix atmospheric dinitrogen, while also utilizing the combined nitrogen absorbed from roots. In this study, nodulated soybean plants were supplied with 5 mM N nitrate, ammonium, or urea for 3 days, and the changes in metabolite concentrations in the xylem sap and each organ were analyzed. The ureide concentration in the xylem sap was the highest in the control plants that were supplied with an N-free nutrient solution, but nitrate and asparagine were the principal compounds in the xylem sap with nitrate treatment. The metabolite concentrations in both the xylem sap and each organ were similar between the ammonium and urea treatments. Considerable amounts of urea were present in the xylem sap and all the organs among all the treatments. Positive correlations were observed between the ureides and urea concentrations in the xylem sap as well as in the roots and leaves, although no correlations were observed between the urea and arginine concentrations, suggesting that urea may have originated from ureide degradation in soybean plants, possibly in the roots. This is the first finding of the possibility of ureide degradation to urea in the underground organs of soybean plants.

The natural abundance of 15N in an irrigated soybean crop and its use for the calculation of nitrogen fixation

1985 ◽  
Vol 36 (3) ◽  
pp. 411 ◽  
Author(s):  
FJ Bergersen ◽  
GL Turner ◽  
RR Gault ◽  
DL Chase ◽  
J Brockwell
Keyword(s):  
Soil Nitrogen ◽  
N2 Fixation ◽  
Plant Size ◽  
Natural Abundance ◽  
Available Nitrogen ◽  
Plant Nitrogen ◽  
Residual Nitrogen ◽  
Stages Of Growth ◽  
Plant Available Nitrogen ◽  
Grain Nitrogen

In a field experiment at Leeton, N.S.W., Chaffey soybeans were grown with irrigation at various plant spacings and with various inoc~ilation treatments and two pre-planting soil treatments. Uninoculated plants were almost completely non-nodulated. Measurements of the natural abundance of 15N (S15N) in the total nitrogen of the plants were made at all stages of growth and in the grain at harvest. The 6lSN in all nodulated treatments declined progressively with time in comparison with un-nodulated plants, due to the incorporation of atmospheric N2 of lower 15N concentration than the soil nitrogen. This enabled calculation of the proportions of plant-nitrogen obtained from the soil and by symbiotic N2-fixation. The main findings were as follows: There was a gradient of S15N in plant-available nitrogen across the experimental area. Therefore, treatments were compared by using the nearest non-nodulated plot for the estimate of S15N in plantavailable soil nitrogen. Despite large differences in plant size due to plant spacing, S15N in mature nonnodulated plants did not differ significantly, indicating that the natural abundance of 15N in plantavailable soil nitrogen was uniform in root zones of different sizes. In well-nodulated plants, the proportion (p) of shoot nitrogen derived from N2-fixation increased with time, reaching approximately 70% and 90% in previously fallowed and previously cropped soil respectively, during a period of rapid growth between 78 and 98 d& after planting. The fixed N, in the best-nodulated treatments at (114 days) was 143 and 244 kg N ha-1 respectively for previously fallowed and previously cropped soil. There were consistent trends for increased N2 fixation with increased inoculation rates. In non-nodulated plants, nitrogen recovered in the grain represented most of that present in the shoots at maturity. In well-nodulated treatments, grain nitrogen, although similar in S15N to that of shoots + fruits, represented only 47 and 59% of the 406 and 348 kg N ha-1 present at maturity in shoots + fruits from previously fallowed and previously cropped soils respectively. After harvesting more than 3 t ha-1 of grain, the nitrogen balance in the previously cropped soil, if all of the residual nitrogen in the soybeans could have been retained in the soil, was positive. In the previously fallowed soil there could have been a net depletion of soil nitrogen.

A survey of proportional dependence of subterranean clover and other pasture legumes on N2 fixation in south-west Australia utilizing 15N natural abundance

1994 ◽  
Vol 45 (1) ◽  
pp. 165 ◽  
Author(s):  
P Sanford ◽  
JS Pate ◽  
MJ Unkovich
Keyword(s):  
Soil Ph ◽  
Coastal Region ◽  
Subterranean Clover ◽  
15N Natural Abundance ◽  
Natural Abundance ◽  
Mineral N ◽  
Pasture Production ◽  
Total N ◽  
Study Region ◽  
Plant Nitrogen

In an attempt to understand why pasture production in southern Australia has declined markedly in recent years a survey of the symbiotic performance of the legume component of annual pastures on 81 farms (243 sites) was undertaken in the southern coastal region of Western Australia. The 15N natural abundance technique was used to determine the percentage of plant nitrogen derived from the atmosphere (%Ndfa) using capeweed (Arctotheca calendula) as principal non-fixing reference species. %Ndfa values were then related to edaphic and management information, e.g. soil total nitrogen, soil pH, stocking rates and cropping history of the sites. The principal legume species encountered exhibited similar mean %Ndfa values but substantial variation in symbiotic performance was evident across the sites, viz, Trifolium subterraneum 72%Ndfa (n = 184, range of values encountered 0-100%), Medicago spp. 7l%Ndfa (n = 24, range 7-l00%), Lotus spp. 8l%Ndfa (n = 15, range 1-l00%), Ornithopus compressus 76%Ndfa (n = 15, range 25-100%) and Trifolium balansae 69%Ndfa (n = 7, range 0-100%). In the case of subterranean clover, the most widely occurring species, almost one third (29%) of sites surveyed recorded %Ndfa values within the range 0-65%, suggesting that symbiotic performance might well be quite widely limiting to herbage production in the study region. Of the 24 edaphic and management factors evaluated, only one, %A1 in shoot, DM showed a significant relationship with %Ndfa, with 40% of the pastures surveyed deemed at risk in terms of acidity related aluminium toxicity. Correlations of %Ndfa with soil pH and soil total N produced examples of high values %Ndfa for sub-clover being associated with very low soil pH or high soil N, suggesting possible adaptation of symbiotic partnerships to acidity or high mineral N.

scholarly journals Bradyrhizobium strain and the 15N natural abundance quantification of biological N2 fixation in soybean

2008 ◽  
Vol 65 (5) ◽  
pp. 516-524 ◽  
Author(s):  
Ana Paula Guimarães ◽  
Rafael Fiusa de Morais ◽  
Segundo Urquiaga ◽  
Robert Michael Boddey ◽  
Bruno José Rodrigues Alves
Keyword(s):  
N2 Fixation ◽  
B Value ◽  
15N Natural Abundance ◽  
Natural Abundance ◽  
Soil Conditions ◽  
Total N ◽  
Biological N2 Fixation ◽  
Bradyrhizobium Strain ◽  
Shoot Tissue ◽  
Biological Nitrogen

In commercial plantations of soybean in both the Southern and the Cerrado regions, contributions from biological nitrogen fixation (BNF) are generally proportionately high. When using the 15N natural abundance technique to quantify BNF inputs, it is essential to determine, with accuracy, the 15N abundance of the N derived from BNF (the 'B' value). This study aimed to determine the effect of four recommended strains of Bradyrhizobium spp. (two B. japonicum and two B. elkanii) on the 'B' value of soybean grown in pots in an open field using an equation based on the determination of δ15N natural abundance in a non-labelled soil, and estimate of the contribution of BNF derived from the use of 15N-isotope dilution in soils enriched with 15N. To evaluate N2 fixation by soybean, three non-N2-fixing reference crops were grown under the same conditions. Regardless of Bradyrhizobium strain, no differences were observed in dry matter, nodule weight and total N between labelled and non-labelled soil. The N2 fixation of the soybeans grown in the two soil conditions were similar. The mean 'B' values of the soybeans inoculated with the B. japonicum strains were -1.84 ‰ and -0.50 ‰, while those inoculated with B. elkanii were -3.67 ‰ and -1.0 ‰, for the shoot tissue and the whole plant, respectively. Finally, the 'B' value for the soybean crop varied considerably in function of the inoculated Bradyrhizobium strain, being most important when only the shoot tissue was utilised to estimate the proportion of N in the plant derived from N2 fixation.

Effects of available soil N and rates of inoculation on nitrogen fixation by irrigated soybeans and evaluation of δ15N methods for measurement

1989 ◽  
Vol 40 (4) ◽  
pp. 763 ◽  
Author(s):  
FJ Bergersen ◽  
J Brockwell ◽  
RR Gault ◽  
L Morthorpe ◽  
MB Peoples ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Soil Nitrogen ◽  
N2 Fixation ◽  
Xylem Sap ◽  
Available Nitrogen ◽  
Soil C ◽  
Plant Nitrogen ◽  
Winter Cereals ◽  
Wide Range ◽  
High Yields

Nitrogen fixation by irrigated soybeans (Glycine max (L.) Merr. cv. Forrest) was studied in a field experiment on a grey clay soil at Trangie, N.S.W. during the summer of 1985-86. Cropping with oats during the previous winter diminished the concentration of plant-available nitrogen in the soil from 37.6 to 18.5 mg N kg-1 and induced differences in the natural abundance of 15N (S15N) in this nitrogen. Four rates of liquid inoculation with Bradyrhizobium japonicum strain CB 1809, interacted with soil nitrogen to produce a wide range of nodulation of the soybeans. The following main effects on growth and N2 fixation resulted: (a) Initially, growth and accumulation of plant nitrogen was lower in pre-cropped than in prefallowed soil but N2 fixation was higher. (b) Nitrogen fixation during seed development was high in pre-cropped soil and greatest at the highest rate of inoculation. It resulted in high yields of seed (3.5 t ha-1 with 100 times the normal inoculation) with significantly higher concentration of seed nitrogen than from plants grown in prefallowed soil. (c) With increasing rates of inoculation on the pre-fallowed soil, more uniform nodulation was associated with smaller variances in most of the parameters studied. Other findings included further validation of the S15N method of calculating the proportion (p) of plant nitrogen derived from N2 fixation, with good agreement between treatment effects based on such estimates and those based on the relative concentrations of ureides in vacuum-extracted xylem sap. The values of p from S15N measurements on shoot nitrogen were affected little by inclusion of root nitrogen, and similar values were obtained when uninoculated, unnodulated Forrest soybeans, a nonnodulating genotype (non-nod Clark 63) or extractable mineral nitrogen of soil were used to estimate the S15N of plant N assimilated from soil. More dry matter (flowers, young pods and older leaves) containing more nitrogen (23-26 kg N ha-1) fell from the canopy of plants during seed maturation on pre-fallowed soil (high nitrogen) than on pre-cropped soil (13-15 kg N ha-1). Several correlations between the various quantities measured were noted and are discussed. It is concluded that growing winter cereals on land newly broken from pasture, coupled with high rates of inoculation of the following soybeans, may be a profitable way of diminishing plant-available soil nitrogen, thus maximizing the contribution of nitrogen from N2 fixation with benefits in seed yield and protein content.

Differential responses of the sunn4 and rdn1-1 super-nodulation mutants of Medicago truncatula to elevated atmospheric CO2

2021 ◽  
Author(s):  
Yunfa Qiao ◽  
Shujie Miao ◽  
Jian Jin ◽  
Ulrike Mathesius ◽  
Caixian Tang
Keyword(s):  
Nitrogen Fixation ◽  
Elevated Co2 ◽  
Medicago Truncatula ◽  
N2 Fixation ◽  
Sink Strength ◽  
Wild Type ◽  
Total N ◽  
Autoregulation Of Nodulation ◽  
Nodulation Mutants ◽  
Fixation Capacity

Abstract Background and Aims Nitrogen fixation in legumes requires tight control of carbon and nitrogen balance. Thus, legumes control nodule numbers via an autoregulation mechanism. ‘Autoregulation of nodulation’ mutants super-nodulate and are thought to be carbon-limited due to the high carbon-sink strength of excessive nodules. This study aimed to examine the effect of increasing carbon supply on the performance of super-nodulation mutants. Methods We compared the responses of Medicago truncatula super-nodulation mutants (sunn-4 and rdn1-1) and wild type to five CO2 levels (300-850 μmol mol -1). Nodule formation and N2 fixation were assessed in soil-grown plants at 18 and 42 days after sowing. Key results Shoot and root biomass, nodule number and biomass, nitrogenase activity and fixed-N per plant of all genotypes increased with increasing CO2 concentration and reached the maximum around 700 μmol mol -1. While the sunn-4 mutant showed strong growth-retardation compared to wild-type plants, elevated CO2 increased shoot biomass and total N content of rdn1-1 mutant up to two-fold. This was accompanied by a four-fold increase in nitrogen fixation capacity in the rdn1-1 mutant. Conclusions These results suggest that the super-nodulation phenotype per se did not limit growth. The additional nitrogen fixation capacity of the rdn1-1 mutant may enhance the benefit of elevated CO2 on plant growth and N2 fixation.

Time of Application of Nitrogen Fertilizer to Maize at Samaru, Nigeria

1973 ◽  
Vol 9 (2) ◽  
pp. 113-120 ◽  
Author(s):  
M. J. Jones
Keyword(s):  
Nitrogen Nutrition ◽  
N Uptake ◽  
Rainfall Distribution ◽  
Total N ◽  
Plant Nitrogen ◽  
Yield Increase ◽  
Time Of Application ◽  
Nitrate N ◽  
One Year

SUMMARYMaize was grown for three years at three levels of nitrogen, 56, 112 and 224 kg. N ha.−1, involving altogether nine different timing and splitting treatments. Measurements were made of grain yield, plant nitrogen status and total-N-uptake, and, in one year, movement of nitrate-N in control plot soils. Where only 56 kg. N ha.−1was applied, its time of application made very little difference to yield; at higher rates of nitrogen an unsplit application as late as seven weeks was very inefficient, but only at the highest rate did a split application give any appreciable yield increase over an unsplit application to the seed bed. Consideration of the soil nitrate-N data and the long-term pattern of rainfall distribution leads to the conclusion that leaching is unlikely to be a serious problem in the nitrogen nutrition of early-planted maize.

Associative N2-fixation in plants growing in saline sodic soils and its relative quantification based on15N natural abundance

1991 ◽  
Vol 137 (1) ◽  
pp. 67-74 ◽  
Author(s):  
K. A. Malik ◽  
Rakhshanda Bilal ◽  
G. Rasul ◽  
K. Mahmood ◽  
M. I. Sajjad
Keyword(s):  
N2 Fixation ◽  
Natural Abundance ◽  
Relative Quantification ◽  
Sodic Soils ◽  
Associative N2 Fixation
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