Sealed-tube combustion for natural 15N abundance estimation of N2 fixation and application to supernodulating soybean mutants

1992 ◽  
Vol 38 (6) ◽  
pp. 598-603 ◽  
Author(s):  
D. L. Eskew ◽  
P. M. Gresshoff ◽  
M. Doty ◽  
C. Mora
Keyword(s):  
Harvest Index ◽  
Isotope Fractionation ◽  
Soybean Seed ◽  
Abundance Estimation ◽  
Soil N ◽  
Physiological Maturity ◽  
Kjeldahl Method ◽  
N Harvest Index ◽  
Combustion Technique ◽  
15N Abundance

Measurement of biological N2 fixation by the natural 15N abundance technique is based on the fact that soil N is usually enriched in 15N compared with atmospheric N2. The technique has been limited by the care required to prevent isotope fractionation in the Kjeldahl method. We describe a sealed-tube combustion technique that reduces isotope fractionation problems. Plant samples were combusted at 850 °C in Vycor tubes with Cu, CuO, CaO, and Ag foil, and N2 gas was admitted directly into the mass spectrometer. A δ15N value of 5.43 ± 0.01 (SE, n = 11) was obtained for a nonnodulating soybean seed sample. This method was used to estimate N2 fixation by soybean cv. Bragg and three supernodulating mutants, nts246, nts382, and nts1007, in the field. Average percent N derived from the atmosphere was 70 ± 4% in vegetative parts at physiological maturity and 72 ± 2% in the grain at harvest. No significant differences were found. The N harvest index averaged 77%; thus, despite the high percent N derived from the atmosphere, these soybean crops would have been net exporters of soil N. The natural 15N abundance method consistently gave estimates of N2 fixation that were 60–90 kg N ha−1 higher than the N difference method. Key words: sealed-tube combustion, natural 15N abundance, supernodulating soybean mutants, biological N2 fixation.

A Visual Indicator of the Physiological Maturity of Soybean Seed 1

Crop Science ◽  
1978 ◽  
Vol 18 (5) ◽  
pp. 867-870 ◽  
Author(s):  
R. Kent Crookston ◽  
David S. Hill
Keyword(s):  
Soybean Seed ◽  
Physiological Maturity

scholarly journals Multiplicación de semilla de variedades y ecotipos de quinua en valle de majes-Arequipa

2016 ◽  
Vol 17 (3) ◽  
pp. 355
Author(s):  
Saturnino Marca Vilca ◽  
Espinoza Espinoza ◽  
Alfonso Poblete Vidal
Keyword(s):  
Plant Height ◽  
Seed Yield ◽  
Biological Material ◽  
Harvest Index ◽  
Biomass Yield ◽  
Growing Season ◽  
White Variety ◽  
Physiological Maturity ◽  
Black And White ◽  
Biological Yield

<p align="center"><strong> RESUMEN </strong></p><p>Con el objetivo de evaluar el potencial de comportamiento, adaptación y rendimiento de semilla de variedades mejoradas y ecotipos de quinua en condiciones de valle de Majes-Arequipa, se utilizó como material biológico las variedades Salcedo INIA, Kancolla, Blanca de Juli, Illpa INIA, Negra Collana y Blanca de Junín, y los ecotipos Choclito, Chullpi blanco y Qoitu procedentes del altiplano de Puno; las estimaciones de rendimiento y otras observaciones se realizaron en un área de 72 m<sup>2</sup> con tres repeticiones, se evaluaron la  altura de planta, días a madurez fisiológica, rendimiento de semilla, rendimiento de biomasa, índice de cosecha. Los resultados indican que la mayor altura de planta alcanzó la variedad Blanca de Junín con 165 cm y la menor altura correspondió a la variedad Kancolla con 126 cm; en relación al ciclo biológico, la variedad Kancolla y el ecotipo Qoitu se mostraron  como precoces, la Salcedo INIA, Blanca de Juli, Illpa INIA y el ecotipo Choclito como semi precoces y la Blanca de Junín y el ecotipo Chullpi Blanco como tardíos; el mayor rendimiento de semilla obtuvieron las variedades Blanca de Juli, Kancolla y Salcedo INIA con 3690, 3488 y 3008 kg ha<sup>-1</sup>, respectivamente; en ecotipos el Choclito alcanzó mayor rendimiento con 3484 kg ha<sup>-1</sup> y el menor correspondió al ecotipo Qoitu con 2632 kg ha<sup>-1</sup>; el mayor rendimiento biológico logró la variedad Blanco de Juli con 10,000 kg ha<sup>-1</sup>, y el menor la variedad Blanca de Junín con 4,533 kg ha<sup>-1</sup>; el 40% de  índice de cosecha obtuvo el ecotipo Choclito y el 37% las variedades Kancolla y Blanca de Juli.</p><p> </p><p align="center"><strong>ABSTRACT</strong></p><p align="center"><strong> </strong></p><p>In order to evaluate the potential behavior, adaptation and seed yield of improved varieties and ecotypes of quinoa in terms of Arequipa Majes valley, was used as biological material Salcedo INIA, Kancolla, Blanca Juli, Illpa INIA, Collana Black and White Junin varieties and Choclito, white Chullpi and Qoitu ecotypes from the highlands of Puno; The estimates were made on an area of 72 m<sup>2</sup> with three repetitions, plant height, days to physiological maturity, seed yield, biomass yield, harvest index were evaluated. The results indicate that most plant height reached the White variety of Junin 165 cm height and the lowest corresponded to the variety Kancolla 126 cm; in relation to the growing season, the variety and ecotype Qoitu  Kancolla were as precocious, Salcedo INIA, Juli White, Illpa INIA and semi ecotype Choclito as early and Junin White and White as late Chullpi ecotype; the highest seed yield obtained Juli white varieties, and Salcedo INIA, Kancolla with 3690, 3488 and 3008 kg ha<sup>-1</sup>, respectively; Choclito ecotypes obtained in the highest performance with 3484 kg ha<sup>-1</sup> and the lowest corresponded to ecotype Qoitu with 2632 kg ha<sup>-1</sup>; the highest biological yield obtained the variety White Juli 10,000 kg ha<sup>-1</sup>, and lower the Junin White variety With 4,533 kg ha<sup>-1</sup>; Choclito ecotype reached 40% of harvest index and 37% of the Kancolla and White Juli varieties.</p><p> </p>

scholarly journals Respiratory activity for the differentiation of vigor on soybean seeds lots

2009 ◽  
Vol 31 (2) ◽  
pp. 171-176 ◽  
Author(s):  
Cristina Rodrigues Mendes ◽  
Dario Munt de Moraes ◽  
Maria da Graça de Souza Lima ◽  
Nei Fernandes Lopes
Keyword(s):  
Respiratory Activity ◽  
Seedling Emergence ◽  
Soybean Seed ◽  
Dry Mass ◽  
Soybean Seeds ◽  
Physiological Maturity ◽  
Conditioning Period ◽  
Short Period ◽  
Physiological Quality

Currently, the highest interest with respect to the assessment of seed physiological quality is to obtain reliable results in a relatively short period of time. This initiative allows for prompt decisions during different phases of seed production primarily after physiological maturity. This research was performed to verify the efficiency and rapidity of the method of Pettenkofer to determine the respiratory activity and to differentiate vigor levels of soybean seed lots. Three lots of soybean seeds cv. 8000 were used. Seed performance was determined by respiratory activity, compared to the following tests: standard germination, germination first count, electrical conductivity, seedling emergence, seedling shoot and root length and total dry mass. Results ranked seed lots according to defferences in physiological quality. Seed imbibition and conditioning period in Pettenkofer's equipment were enough to detect differences in vigor among seed lots, showing that the determination of the respiratory activity is a promising procedure to identify differences in vigor levels among soybean seed lots.

Aridity-controlled hydrogen isotope fractionation between soil n-alkanes and precipitation in China

2019 ◽  
Vol 133 ◽  
pp. 53-64 ◽  
Author(s):  
Yangyang Li ◽  
Shiling Yang ◽  
Pan Luo ◽  
Shangfa Xiong
Keyword(s):  
Hydrogen Isotope ◽  
Isotope Fractionation ◽  
Soil N

CHANGES IN NATURAL 15N ABUNDANCE ASSOCIATED WITH PEDOGENIC PROCESSES IN SOIL. I. CHANGES ASSOCIATED WITH SALINE SEEPS

1980 ◽  
Vol 60 (2) ◽  
pp. 337-344 ◽  
Author(s):  
R. E. KARAMANOS ◽  
D. A. RENNIE
Keyword(s):  
Organic Nitrogen ◽  
Soil N ◽  
Soluble Salts ◽  
Recharge Area ◽  
Surface Samples ◽  
Nitrate N ◽  
Dominant Process ◽  
Pedogenic Processes ◽  
Very High ◽  
15N Abundance

The δa15N for the total and nitrate soil N from surface samples taken from recharge and discharge areas associated with a saline seep differ significantly. Suggested reasons for these differences are included. These data suggest that the nitrate moving towards the surface with the soluble salts is depleted in the heavier isotope; the very high δa15N for total and nitrate N of surface samples suggests that denitrification has been a dominant process operating in the saline seep area. Incubation studies carried out on Ap samples taken from the recharge and discharge areas have verified that the δa15N (and perhaps also the nature of the mineralizable organic nitrogen) from a "mature" and "recent" saline profile are different from each other, and distinctly different from that of the recharge area.

scholarly journals Differences in grain growth, crop photosynthesis and distribution of assimilates between a semi-dwarf and a standard cultivar of winter wheat.

1978 ◽  
Vol 26 (3) ◽  
pp. 233-249
Author(s):  
J.H.J. Spiertz ◽  
H. van de Haar
Keyword(s):  
Grain Yield ◽  
Harvest Index ◽  
Grain Filling ◽  
Water Soluble ◽  
Soluble Carbohydrates ◽  
Grain Number ◽  
Photosynthetic Production ◽  
Grain Filling Period ◽  
N Harvest Index ◽  
Standard Cultivar

The crop performance of semi-dwarf wheat cv. (Maris Hobbit) was compared with a standard-ht. cv. (Lely) at various levels of N supply. The grain yields of Maris Hobbit were considerably higher due to a higher number of grains and a heavier grain wt. Owing to the higher grain yield and a lower stem wt. the harvest index of Maris Hobbit was higher than that of Lely (0.47 and 0.40, resp.). The content of water-soluble carbohydrates in the stems of both cv. appeared to be very high until 3 wk after anthesis, despite the occurrence of low light intensities. Lely used more assimilates for structural stem material than did Maris Hobbit. Quantity and date of N application greatly affected grain number, but affected grain wt. to a lesser extent. Thus within each cv. grain number/m2 was the main determinant of grain yield. Late N dressings promoted photosynthetic production, grain wt. and CP content of the grain. The low CP contents of the grain were attributed to the low temp. during the grain-filling period. The distribution of N within the plant was only slightly influenced by N dressings and cv. differences. N harvest index ranged from 0.74 to 0.79. Grain N was derived from the vegetative organs (63-94%) and from uptake after anthesis (6-37%). The importance of carbohydrate and N economy for grain yield are discussed. (Abstract retrieved from CAB Abstracts by CABI’s permission)

Natural abundance of 15N in barley as influenced by prior cropping or fallow, nitrogen fertilizer and tillage

1991 ◽  
Vol 42 (5) ◽  
pp. 723 ◽  
Author(s):  
JA Doughton ◽  
PG Saffigna ◽  
I Vallis
Keyword(s):  
Nitrogen Fertilizer ◽  
Isotope Fractionation ◽  
Soil Surface ◽  
Grain Sorghum ◽  
Natural Abundance ◽  
Soil Mineral ◽  
Soil Mineral Nitrogen ◽  
Large Excess ◽  
15N Enrichment ◽  
15N Abundance

The 15N abundance of nitrogen was measured in barley grown with 0, 50 and 100 kg/ha of applied nitrogen after pretreatments of either fallow or grain sorghum, where sorghum stubble was either incorporated, removed or retained on the soil surface (zero-till). Barley 15N abundance was assumed to reflect that of assimilated soil mineral nitrogen. Fallowing soil prior to establishment of barley accumulated 226 kg NO3-N/ha to a depth of 120 cm and resulted in an 88% increase in 15N enrichment of nitrogen in barley compared with that grown after sorghum. 15N enrichment was assumed to be mostly the result of isotope fractionation between 14N and 15N during denitrification of the large excess of NO3-N present prior to and during the experiment. Nitrogen fertilizer additions caused 15N depletion of nitrogen in barley. However, where fertilizer additions resulted in excess availability of NO3-N, subsequent denitrification and 15N enrichment of this NO3-N partially counterbalanced the 15N depleting effect of fertilizer additions. Where soil NO3-N levels were low (<25 kg NO3-N/ha) following sorghum there were no differences in 15N abundance of nitrogen in barley between tillage treatments. With additions of nitrogen fertilizer and the availability of excess NO3-N for denitrification, differences between tillage treatments occurred with some being significant. The ranking of stubble management treatments in terms of their effect on 15N enrichment of nitrogen in barley was incorporated > removed > surface retained.

Comparison of the Automatic Dumas (Coleman Model 29A Nitrogen Analyzer II) and Kjeldahl Methods for the Determination of Total Nitrogen in Agricultural Materials

1968 ◽  
Vol 51 (1) ◽  
pp. 216-219 ◽  
Author(s):  
G F Morris ◽  
R B Carson ◽  
D A Shearer ◽  
W T Jopkiewicz
Keyword(s):  
Experimental Data ◽  
Standard Deviation ◽  
Total Nitrogen ◽  
Statistical Evaluation ◽  
Kjeldahl Method ◽  
Agricultural Materials ◽  
Combustion Technique

Abstract A wide variety of agricultural materials were analyzed for total nitrogen by the Kjeldahl and automatic Dumas methods. The recoveries of nitrogen compared favorably by both methods when a catalystassisted combustion technique was used in the automatic Dumas method. Statistical evaluation of the experimental data, as measured by standard deviation, showed that the Kjeldahl method was generally more precise than the automatic Dumas method

scholarly journals Growth Rate, Dry Matter Accumulation, and Partitioning in Soybean (Glycine max L.) in Response to Defoliation under High-Rainfall Conditions

Plants ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1497
Author(s):  
Muhammad Ali Raza ◽  
Hina Gul ◽  
Feng Yang ◽  
Mukhtar Ahmed ◽  
Wenyu Yang
Keyword(s):  
Seed Yield ◽  
Dry Matter ◽  
Soybean Seed ◽  
Growth And Yield ◽  
Light Transmittance ◽  
Dry Matter Accumulation ◽  
Physiological Maturity ◽  
High Rainfall ◽  
Soybean Plants ◽  
Initiation Stage

The frequency of heavy rains is increasing with climate change in regions that already have high annual rainfall (i.e., Sichuan, China). Crop response under such high-rainfall conditions is to increase dry matter investment in vegetative parts rather than reproductive parts. In the case of soybean, leaf redundancy prevails, which reduces the light transmittance and seed yield. However, moderate defoliation of soybean canopy could reduce leaf redundancy and improve soybean yield, especially under high-rainfall conditions. Therefore, the effects of three defoliation treatments (T1, 15%; T2, 30%; and T3, 45% defoliation from the top of the soybean canopy; defoliation treatments were applied at the pod initiation stage of soybean) on the growth and yield parameters of soybean were evaluated through field experiments in the summer of 2017, 2018, and 2019. All results were compared with nondefoliated soybean plants (CK) under high-rainfall conditions. Compared with CK, treatment T1 significantly (p < 0. 05) improved the light transmittance and photosynthetic rate of soybean. Consequently, the leaf greenness was enhanced by 22%, which delayed the leaf senescence by 13% at physiological maturity. Besides, compared to CK, soybean plants achieved the highest values of crop growth rate in T1, which increased the total dry matter accumulation (by 6%) and its translocation to vegetative parts (by 4%) and reproductive parts (by 8%) at physiological maturity. This improved soybean growth and dry matter partitioning to reproductive parts in T1 enhanced the pod number (by 23%, from 823.8 m−2 in CK to 1012.7 m−2 in T1) and seed number (by 11%, from 1181.4 m−2 in CK to 1311.7 m−2 in T1), whereas the heavy defoliation treatments considerably decreased all measured growth and yield parameters. On average, treatment T1 increased soybean seed yield by 9% (from 2120.2 kg ha−1 in CK to 2318.2 kg ha−1 in T1), while T2 and T3 decreased soybean seed yield by 19% and 33%, respectively, compared to CK. Overall, these findings indicate that the optimum defoliation, i.e., T1 (15% defoliation), can decrease leaf redundancy and increase seed yield by reducing the adverse effects of mutual shading and increasing the dry matter translocation to reproductive parts than vegetative parts in soybean, especially under high-rainfall conditions. Future studies are needed to understand the internal signaling and the molecular mechanism controlling and regulating dry matter production and partitioning in soybean, especially from the pod initiation stage to the physiological maturity stage.

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