Analysis of the Carbon and Nitrogen Limitations to Soybean Yield<sup>1</sup>

Sinclair, Thomas R.; Wit, C.T. de

doi:10.2134/agronj1976.00021962006800020021x

Cited by 287 publications

(129 citation statements)

References 10 publications

Supporting

Mentioning

117

Contrasting

Unclassified

Order By: Relevance

“…Of course, the complex geometry and biochemistry of nodules ' MATERIALS AND METHODS Estimation of Flows. We will approach the quantification of the flows from a realistic agronomic goal of a nitrogen fixation rate of 2 kg N ha-' day-' (13). We will consider a soybean crop with a plant population of 2 x 105 plants ha-' and with 100 nodules/ plant.…”

mentioning

confidence: 99%

Physical and Morphological Constraints on Transport in Nodules

Sinclair

Goudriaan²

1981

Plant Physiol.

View full text Add to dashboard Cite

MATERIALS AND METHODS Estimation of Flows. We will approach the quantification of the flows from a realistic agronomic goal of a nitrogen fixation rate of 2 kg N ha-' day-' (13). We will consider a soybean crop with a plant population of 2 x 105 plants ha-' and with 100 nodules/ plant. Each nodule then will be assumed to fix nitrogen at a rate of about 1 x 10-9 g N s-'. This number will be used to estimate first the required flow of glucose and then of 02.Glucose is required in the nitrogen fixation process as a source of energy and carbon skeletons and as the substrate for sustaining maintenance respiration in the nodule. On the basis of the theoretical considerations of Penning de Vires (10, 11), it is possible to construct the following reaction for the fixation of 1 g N: 15.5 g glucose + 6 g2 + 1 g N2 x 7 g amino acids + 10.7 g CO2 + 4.8 g H20 Experimentally, Ryle et al. (12) measured the CO2 loss from nodules of soybean, cowpea, and clover. Expressing this loss/g nitrogen fixed, full-grown, nonsenesced nodules were found to lose 3 to 4 g C/g N fixed. Converting this ratio to CO2 loss yields 4 x 44/12 = 14.7 g CO2 evolved, or 4.0 g more than derived above. This excess CO2 loss can be attributed to maintenance respiration and represents an additional glucose requirement of about 2.7 g. Approximately 18 g glucose is used by the nodule during its fixation of 1 g N or, to meet the agronomic goals, about 18 x 10-9 g glucose s-1 needs to be imported by a nodule.A similar approach can be used to estimate the 02 requirement.From the reaction above, 6 g 02 is required in fixation itself and maintenance respiration requires 2.9 g 02. Consequently, approximately 8.9 g 02 is required during the fixation of 1 g N, and the agronomic goal requires 8.9 x 10-9 g 02 s' to be obtained by a nodule from the surrounding atmosphere.Model. A second-order differential equation can be used to define material transport in the nodule after invoking several simplifying assumptions. It is assumed that the nodule is a uniform, homogeneous sphere because this geometry reasonably approximates many nodules and it allows an analytic solution. The biochemical events of N2 fixation are assumed to be reasonably 143 www.plantphysiol.org on May 7, 2018 -Published by Downloaded from

show abstract

mentioning

confidence: 99%

Physical and Morphological Constraints on Transport in Nodules

Sinclair

Goudriaan²

1981

Plant Physiol.

View full text Add to dashboard Cite

show abstract

“…This is substantially less than the levels found in the translocation path of soybeans (10,12), but might be expected since the protein concentration and hence the nitrogen demand of corn is much lower than in soybeans (20).…”

Section: Resultsmentioning

confidence: 72%

Source-Sink Relations in Maize Mutants with Starch-Deficient Endosperms

Koch¹,

Tsui²,

Schrader³

et al. 1982

Plant Physiol.

View full text Add to dashboard Cite

Partitioning and translocation of photosynthates were compared between a nonmutant genotype (Oh 43) of corn (Zea mays L.) and two starchdeficient endosperm mutants, shrunken-2 (sh2) and brittk-i (btl), with similar genetic backgrounds. Steady-state levels of "CO2 were supplied to source leaf blades for 2-hour periods, folowed by separation and identification of "C-assimilates in the leaf, kernel, and along the translocation path. An average of 14.1% of the total "C assimilated was translocated to normal kernels, versus 0.9% in sh2 kernels and 2.6% in bd kernels. Over 98% of the kernel 14C was in free sugars, and further analysis of nonmutant kernels showed 46% of this label in glucose and fructose. Source leaves of mutant plants exported significantly less total photosynthate (24.0% and 36.3% in sh2 and btl compared to 48.0% in the normal plants) and accumulated greater portions of label in the insoluble (starch) fraction. Mutant plants also showed lower percentages of photosynthate in the leaf blade and sheath below the exposed blade area. The starch-deficient endosperm mutants influence the partitioning and translocation of photosynthates and provide a valuable tool for the study of source-sink relations.A high economic yield of grain crops depends on efficient translocation of assimilates to kernel sink tissues. In the present study, maize mutants with reduced kernel capacity for starch accumulation have been used to examine the effects of sink strength on partitioning of assimilates in source leaves and their subsequent distribution within the plant. There are several advantages to using plants with mutations affecting sink metabolism for such a study. First, mechanical manipulation of source leaves or sink tissues can be avoided. Such manipulations might result in short-term decreases in phloem functioning (6) or atypical changes in the hormonal balance within the plant (9). Secondly, inhibitors are not used, avoiding other possible secondary effects (25).Two maize mutants, brittle-J (btl) and shrunken-2 (sh2), synthesize about 25% of the starch of nonmutant endosperms and consequently have shrunken endosperms at maturity (15 MATERIALS AND METHODS PLANT MATERIAL. Three corn genotypes were examined in this study; 'nonmutant' inbred (Oh 43) of maize (Zea mays L.), and two starch-deficient mutants, shrunken-2 and brittle-i in the same genetic background. We will refer to homozygous mutant sh2/sh2 plants as sh2 plants and to homozygous mutant seeds (sh2/sh2 embryos with associated sh2/sh2/sh2 endosperms) as sh2 seeds. The same type of abbreviation is used for brittle-i.Plants were grown in the field using 12-liter buried metal containers, watered as needed during the growing season, and selfpollinated. Development proceeded at rates similar to other fieldgrown inbreds. Experimental plants were transported to the laboratory for studies done hetween 20 and 23 d after pollination. "CO2 Labeling. Two-h, steady-state labeling studies were done by supplying 1'CO2 to a source leaf blade of each plant. The ear ...

show abstract

“…The N concentration of several parts of the plant (green and yellow leaves, stems, and pods) was measured and included in the model (calibration values in Table 2). In the reproductive phase, the decrease in leaf N leads to leaf senescence and to the reduction of leaf assimilation (Sinclair & De Wit, 1976). …”

Section: Methodsmentioning

confidence: 99%

Simulation of soybean growth and yield under northeastern Amazon climatic conditions

Souza

Farias

Abreu³

et al. 2011

Pesq. agropec. bras.

View full text Add to dashboard Cite

-The objective of this work was to parameterize, calibrate, and validate a new version of the soybean growth and yield model developed by Sinclair, under natural field conditions in northeastern Amazon. The meteorological data and the values of soybean growth and leaf area were obtained from an agrometeorological experiment carried out in Paragominas, PA, Brazil, from 2006 to 2009. The climatic conditions during the experiment were very distinct, with a slight reduction in rainfall in 2007, due to the El Niño phenomenon. There was a reduction in the leaf area index (LAI) and in biomass production during this year, which was reproduced by the model. The simulation of the LAI had root mean square error (RMSE) of 0.55 to 0.82 m 2 m -2, from 2006 to 2009. The simulation of soybean yield for independent data showed a RMSE of 198 kg ha -1 , i.e., an overestimation of 3%. The model was calibrated and validated for Amazonian climatic conditions, and can contribute positively to the improvement of the simulations of the impacts of land use change in the Amazon region. The modified version of the Sinclair model is able to adequately simulate leaf area formation, total biomass, and soybean yield, under northeastern Amazon climatic conditions. Index terms: Glycine max, Amazon region, climate models, leaf area index, soybean crop expansion, yield simulation. Simulação do crescimento e da produtividade da soja nas condições climáticas do nordeste da AmazôniaResumo -O objetivo deste trabalho foi parametrizar, calibrar e validar uma nova versão do modelo de crescimento e de produtividade da soja desenvolvido por Sinclair, em condições naturais de campo no nordeste da Amazônia. , ou seja, uma superestimativa de 3%. O modelo encontra-se calibrado e validado para as condições climáticas da Amazônia e pode contribuir positivamente para a melhoria das simulações dos impactos da mudança de uso da terra na região amazônica. A versão modificada do modelo de Sinclair simula adequadamente a formação de área foliar, a biomassa total e a produtividade da soja, nas condições climáticas do nordeste da Amazônia.Termos para indexação: Glycine max, região Amazônica, modelos climáticos, índice de área foliar, expansão da cultura da soja, simulação de produtividade.

show abstract

Analysis of the Carbon and Nitrogen Limitations to Soybean Yield¹

Cited by 287 publications

References 10 publications

Physical and Morphological Constraints on Transport in Nodules

Physical and Morphological Constraints on Transport in Nodules

Source-Sink Relations in Maize Mutants with Starch-Deficient Endosperms

Simulation of soybean growth and yield under northeastern Amazon climatic conditions

Contact Info

Product

Resources

About

Analysis of the Carbon and Nitrogen Limitations to Soybean Yield1

Cited by 287 publications

References 10 publications

Physical and Morphological Constraints on Transport in Nodules

Physical and Morphological Constraints on Transport in Nodules

Source-Sink Relations in Maize Mutants with Starch-Deficient Endosperms

Simulation of soybean growth and yield under northeastern Amazon climatic conditions

Contact Info

Product

Resources

About

Analysis of the Carbon and Nitrogen Limitations to Soybean Yield¹