Mineral Depletion and Leaf Senescence in Soya Bean as Influenced by Foliar Nutrient Application During Seed Filling*

Sesay, A.; Shibles, Richard

doi:10.1093/oxfordjournals.aob.a085800

Cited by 65 publications

(33 citation statements)

References 11 publications

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“…We observed that net amino acid efflux was generally about 0.250 nmol amino-N.min-'. 10 (15,18,20,28). Thus, our experimental system seems to be physiologically relevant to whole-plant studies.…”

Section: Discussionmentioning

confidence: 97%

Characterization of Amino Acid Efflux from Isolated Soybean Cells

Secor

Schrader²

1984

Plant Physiol.

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Cells from reproductive soybean (Glycine max [L.] Menf.) plants were isolated using a mechanical-enzymic technique that produced a high yield of uniform, physiologically active cells. Cells were incubated in a pH 6.0 buffered solution and subjected to various treatments in order to determine the nature of net amino acid efflux. Total net amino acid (ninhydrinreactive substances) efflux was not affected by the following conditions: (a) darkness, (b) aeration, (c) K' concentrations of 0.1, 1.0, 10, or 100 millimolar and (d) pH 4, 5, 6, 7, or 8. The Qio for net amino acid efflux between 10°C and 30'C was 1.6. Thus, it seems that net amino acid efflux requires neither current photosynthetic energy nor a pH/ion concentration gradient. Amino acid analyses of the intra-and extracellular fractions over time showed that each amino acid was exported linearly for at least 210 minutes, but that export rate was not necessarily related to internal amino acid pools. Amino acids that were exported fastest were alanine, lysine, leucine, and glycine. Addition of the inhibitor p-chloromercuriphenyl sulfonic acid, 3(3,4-dichlorophenyl)-1,1-dimethylurea, or carbonylcyanide p-trifluoromethoxyphenylhydrazone increased the rate of total amino acid efflux but had specific effects on the efflux of certain amino acids. For example,p-chloromercuriphenyl sulfonic acid greatly enhanced efflux of -y-aminobutyric acid, which is not normally exported rapidly even though a high concentration normally exists within cells. The data suggest that net amino acid efflux is a selective diffusional process. Because net efflux is the result of simultaneous efflux and influx, we propose that efflux is a facilitated diffusion process whereas influx involves energy-dependent carrier proteins.Mature soybean seeds contain about 6% N, primarily as storage protein. Approximately half of this N is remobilized (translocated) from vegetative tissue when the plant has a reduced capacity for assimilating atmospheric and soil N during the time of rapid seed growth (9). This syndrome of satisfying the N demand by degradation of leaf protein and the subsequent remobilization of N to the seeds has been referred to as the "self destruction" hypothesis by Sinclair and de Wit (21). Attempts to overcome this "self destruction" and improve soybean yields by using soil or foliar N fertilizer applications have been inconclusive (3,4,7,25). This suggests an inability of the leaf to absorb and/or assimilate the applied N, or a limitation on N transport within the plant.

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Section: Discussionmentioning

confidence: 97%

Characterization of Amino Acid Efflux from Isolated Soybean Cells

Secor

Schrader²

1984

Plant Physiol.

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“…of their final dry weight at R6.5, analysis of plants harvested at this stage allowed the examination of S redistribution due to nutrient stress prior to the rapid and extensive 66 mobilization that normally occurs just before physiological maturity in non-stressed plants (Wittenbach et al, 1980;Sesay and Shibles, 1980;Boon-Long et aL, 1982). Developing soybean seed produce a senescence signal quite late in seed development (Nooden and Leopold, 1988).…”

Section: Discussionmentioning

confidence: 99%

“…In general, nutrient stress before R6.5 showed only minor effects on mobilization compared with stress induced changes after R6.5, which is the major nutrient redistribution phase of soybean development (Wittenbach el al., 1980;Sesay and Shibles, 1980;BoonLong et aL, 1982). Nitrogen stress affected the distribution of N, S, or ^^S in most mature tissues (Table n. Fig.…”

Section: Nitrogen Stress and Nutrient Redistributionmentioning

confidence: 99%

“…They found seeds to be able to accumulate N-free dry matter, and only require a very small amount of N to maintain synthetic enzymes for this dry matter accumulation. Foliar applications of N, P, or K to field grown soybean failed to inhibit the withdrawal of N from leaves during senescence (Sesay and Shibles, 1980).…”

mentioning

confidence: 92%

“…failed to inhibit the withdrawal of N from leaves during senescence, however (Sesay and Shibles, 1980). Sulfur's relative mobility in plants has been contested.…”

Section: Seth L Naeve and Richard Shibles Introductionmentioning

confidence: 98%

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Distribution and Mobilization of Sulfur during Soybean Reproduction

Naeve

Shibles

2005

Crop Science

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This manuscript has been reproduced from the microfilm master. UMI films the text directly from the original or copy submitted. Thus, some thesis and dissertation copies are in typewriter face, while others may be from any type of computer printer.The quality of this reproduction is dependent upon the quality of the copy submitted. Broken or indistinct print, colored or poor quality illustrations and photographs, print bleedthrough, substandard margins, and improper alignment can adversely aflFect reproduction.In the unlikely event that the author did not send UMI a complete manuscript and there are missing pages, these will be noted. Also, if unauthorized copyright material had to be removed, a note will indicate the deletion.Oversize materials (e.g., maps, drawings, charts) are reproduced by sectioning the original, beginning at the upper left-hand comer and continuing from left to right in equal sections with small overiaps. Each original is also photographed in one exposure and is included in reduced form at the back of the book.Photographs included in the original manuscript have been reproduced xerographically in this copy. Higher quality 6" x 9" black and white photographic prints are available for any photographs or illustrations appearing in this copy for an additional charge. Contact UMI directly to order. UMI GENERAL INTRODUCTION Dissertation OrganizationA discussion of results obtained from studies conducted on soybean sulfur metabolism is presented here as two manuscripts for the eventual submission for publication in Crop Science. A general introduction precedes these manuscripts giving a broad overview of plant sulfur metabolism, sulfur transpon, and soybean seed protein accumulation. A general conclusion chapter follows, summarizing findings of the two studies presented here.References cited in this dissertation are coalesced and listed at the end of the dissertation.The first manuscript paper discusses the distribution and mobilization of sulfur acquired by soybean during seed development, while the second takes up nitrogen and sulfur stress effects on mobilization of sulfur to developing soybean seed. RationaleSoybean seed is an important source of dietary protein for livestock and humans;however, soybean seed protein itself contains low, potentially growth-limiting concentrations of the sulfur-containing amino acids, methionine (met) and cysteine (cys), when used as the sole protein source for monogastric mammals. Methionine and cys are considered "essential amino acids" indicating that they cannot be synthesized de novo by monogastric mammals (Food and Agricultural Organization and World Health Organization, 1989). Methionine is the primary essential amino acid that is deficient in legume proteins (DeLumen et al., 1997), and soybean seed proteins contain about half of the met found in FAO's (Food and 2 Agricultural Organization) egg protein standard (Burton et al., 1982). This limitation reveals itself in high protein rations when the majority of the ingested protein is derived from soybean....

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Environmental Influences on Seed Size and Composition

Fenner

1992

Horticultural Reviews

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Mineral Depletion and Leaf Senescence in Soya Bean as Influenced by Foliar Nutrient Application During Seed Filling*

Cited by 65 publications

References 11 publications

Characterization of Amino Acid Efflux from Isolated Soybean Cells

Characterization of Amino Acid Efflux from Isolated Soybean Cells

Distribution and Mobilization of Sulfur during Soybean Reproduction

Environmental Influences on Seed Size and Composition

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