Phosphorus Nutrition Influence on Leaf Senescence in Soybean

Crafts‐Brandner, Steven J.

doi:10.1104/pp.98.3.1128

Cited by 63 publications

(41 citation statements)

References 23 publications

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“…Plant growth adapted such that leaf P concentration was maintained at similar levels for plants that differed widely in biomass production and/or seed yield until P fertility exceeded the level needed for maximum growth. At supraoptimum soil P levels, leaf P concentration was markedly increased (5,6,8).…”

Section: Introductionmentioning

confidence: 99%

Phosphorus Nutrition Influence on Starch and Sucrose Accumulation, and Activities of ADP-Glucose Pyrophosphorylase and Sucrose-Phosphate Synthase during the Grain Filling Period in Soybean

Crafts‐Brandner¹

1992

Plant Physiol.

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Several lines of evidence indicate that the partitioning of photosynthate between starch and sucrose is influenced by the relative concentrations of inorganic phosphate (Pi) in the cytosol and chloroplast. Two greenhouse experiments were conducted to determine the influence of long-term differences in soil P levels, ranging from deficient to supraoptimum, on leaf starch and sucrose concentrations, and activities of adenosine diphosphate glucose (ADPG) pyrophosphorylase and sucrose-phosphate synthase (SPS) during the grain filling period in soybean (Glycine max [L.] Merr.). It was hypothesized that, compared with optimum P nutrition, leaf starch and sucrose concentrations would be increased and decreased, respectively, for P deficiency and visa versa for supraoptimum P nutrition. Relative to the optimum soil P level, leaf Pi concentration was not altered by P deficiency but was increased two-to fourfold for the supraoptimum soil P treatment. The concentrations of leaf starch and sucrose were not markedly affected by any of the P fertility treatments and were not closely related to the activities of ADPG pyrophosphorylase and SPS. P deficiency resulted in increased activity of both enzymes in one of the experiments. The results indicated that long-term soil P treatments, that caused either large decreases in plant growth (P deficiency) or large increases in leaf Pi concentration (supraoptimum P), did not markedly alter starch and sucrose metabolism. Furthermore, it can be inferred that the method of plant culture and/or imposition of the P treatments is a critical factor in interpreting results of P nutrition studies.The regulatory effect of Pi on the partitioning of photosynthate between sucrose and starch has been extensively studied (12,13,18,28,29,(31)(32)(33) at various times during plant development lead to enhanced starch accumulation by leaves (13,14,16,21,25). In general, treatments that alter the relative concentrations of cytosolic and chloroplastic Pi would be expected to alter starch and sucrose synthesis and accumulation. In some cases, alterations in starch and sucrose accumulation have been associated with corresponding changes in enzymes of starch and sucrose metabolism (13). It has been proposed that P deficiency during the seed filling period may decrease yield in soybean by decreasing the flow of carbon into sucrose that could be used for seed development (15).There are a few reports that indicate that P stress does not necessarily result in enhanced starch and/or decreased sucrose accumulation (8,11,29). In a previous study of vegetative development in tobacco (Nicotiana tabacum L.), it was demonstrated that leaf sucrose and starch concentrations were not markedly affected in plants grown at soil P levels ranging from severely deficient to supraoptimum (8). It was proposed that the variable effects of soil P level on starch and sucrose synthesis and accumulation may be due to experimental procedures such as the use of isolated chloroplasts versus leaves, the timing of application of P ...

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Section: Introductionmentioning

confidence: 99%

Phosphorus Nutrition Influence on Starch and Sucrose Accumulation, and Activities of ADP-Glucose Pyrophosphorylase and Sucrose-Phosphate Synthase during the Grain Filling Period in Soybean

Crafts‐Brandner¹

1992

Plant Physiol.

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“…Consequently, the relative contributions of anabolic versus catabolic factors in regulating this process are not well understood (Woolhouse, 1987;Gepstein, 1988;Huffaker, 1990). Decreases in Rubisco activity are a hallmark of the senescence process (Brady, 1988;Gepstein, 1988), especially in soybean (Secor et al, 1984;Ford and Shibles, 1988;Crafts-Brandner, 1992). Although it is commonly assumed that these dècreases reflect enhanced rates of protein degradation (Brady, 1988), severa1 reports have shown a relationship with altered rates of Rubisco subunit synthesis at the transcriptional and translational levels (Brady, 1988;Bate et al, 1991).…”

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confidence: 99%

Photosynthesis, Rubisco Activity and Amount, and Their Regulation by Transcription in Senescing Soybean Leaves

1993

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Senescence is a phase of leaf ontogeny marked by declining photosynthetic activity that, in soybean (Glycine max [L.] Merr.), is paralleled by a decline in chloroplast function. Soybean leaves have different patterns of decline in photosynthetic capacity and chloroplast function associated with nodal position and sink adivity. The objective of this work was to determine whether leaves from nodes 3 and 6 of soybean, which show these different patterns, are similarly regulated with respect to ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) activity and content and also to ascertain the degree of regulation of Rubisco content by transcription. Leaves from nodes 3 and 6 of field-grown soybean plants were sampled periodically from the time of their unfolding until near death. In situ COz-exchange rate (CER) increased to a maximal level in both leaves and then declined slowly. For node 3 leaves the decline was progressive, but for node 6 leaves the decline was arrested at about 75% of maximum CER for a period of about 20 d, coincident with the onset of rapid seed growth, before a short period of very rapid decline immediately preceding leaf death. Rubisco activities and Rubisco content were directly correlated with CER in the leaves exhibiting the two different patterns. Rubisco activation ratio was similar for the two leaves and did not change throughout development. The primary regulator of photosynthesis at the physiological level, thus, was the amount of Rubisco protein. Decreases in Rubisco holoenzyme during senescence of both leaves were accompanied by coordinate decreases in the levels of mRNAs for the small and large subunits of Rubisco, suggesting that the decrease in Rubisco enzyme amounts during soybean leaf senescence is due to slower transcription rates and that levels of these mRNAs are coordinately controlled during senescence as they are during chloroplast development. However, plastid DNA template availability and posttranscriptional controls may also influence Rubisco content during senescence of these leaves. We conclude that soybean leaf photosynthesis likely unfolds according to a single developmental program but that modifications can be superimposed upon this program to maximize photosynthetic rates.

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“…By weekly measures of leaf appearance and loss, Snapp & Lynch (1996) determined a lower leaf longevity in low-P than in high-P common bean plants, but the determinate cultivar Calima they used presented a negligible senesced leaf mass at a high applied P level. Crafts-Brandner (1992) suggested that P nutrition does not exert any regulatory control over leaf senescence, based on evidence that soil P levels that either depressed plant growth or enhanced leaf P concentration did not affect several traits related to senescence process. However, in the cited study, P treatments that did not differ regarding leaf senescence had similar leaf P concentrations (Crafts-Brandner, 1992), and perhaps the observed range of P nutrition was narrow.…”

Section: Discussionmentioning

confidence: 99%

“…Crafts-Brandner (1992) suggested that P nutrition does not exert any regulatory control over leaf senescence, based on evidence that soil P levels that either depressed plant growth or enhanced leaf P concentration did not affect several traits related to senescence process. However, in the cited study, P treatments that did not differ regarding leaf senescence had similar leaf P concentrations (Crafts-Brandner, 1992), and perhaps the observed range of P nutrition was narrow. Some of the contradictory results on the effects of P nutrition on leaf senescence of leguminous crops available in literature may be partially due to different experimental conditions.…”

Section: Discussionmentioning

confidence: 99%

“…Differential responses of leaf senescence and nutrient resorption to P availability could constitute adaptive mechanisms for growth under P-limiting conditions which prevails in tropical soils. The employment of a wider variation of soil P supplies than the relatively few P treatments used in previous studies on leaf senescence of leguminous plants (Grabau et al, 1986;Crafts-Brandner, 1992;Snapp & Lynch, 1996) may contribute to elucidate this issue. This work had the objective to evaluate the effects of varied soil P supply on leaf senescence of common bean (Phaseolus vulgaris L.) plants.…”

Section: Introductionmentioning

confidence: 99%

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Leaf senescence of common bean plants as affected by soil phosphorus supply

Araújo

Kubota²,

Teixeira

2007

Rev. Bras. Ciênc. Solo

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SUMMARYResponses of leaf senescence to P supply could constitute adaptive mechanisms for plant growth under P-limiting conditions. The aim of this study was to evaluate the effects of soil P supply on leaf senescence of common bean (Phaseolus vulgaris L.). Eight P levels, ranging from 5 to 640 mg kg -1 P, were applied to pots containing four bean plants of cultivar Carioca in 10 kg of an Oxic Haplustult soil. Attached leaves were counted weekly, abscised leaves were collected every other day, and seeds were harvested at maturity. The number of live leaves increased until 48 days after emergence (DAE) and decreased afterwards, irrespective of applied P levels. At lower applied P levels, the initial increase and the final decrease of leaf number was weak, whereas at higher applied P levels the leaf number increased intensively at the beginning of the growth cycle and decreased strongly after 48 DAE. Dry matter and P accumulated in senesced leaves increased as soil P levels increased until 61 DAE, but differences between P treatments narrowed thereafter. The greatest amounts of dry mass and P deposited by senesced leaves were observed at 48-54 DAE for high P levels, at 62-68 DAE for intermediate P levels and at 69-76 DAE for low P levels. These results indicate that soil P supply did not affect the stage of maximal leaf number and the beginning of leaf senescence of common bean plants, but the stage of greatest deposition of senesced leaves occurred earlier in the growth cycle as the soil P supply was raised.Index terms: growth, harvest index, ontogeny, Phaseolus vulgaris. RESUMO:SENESCÊNCIA FOLIAR DO FEIJOEIRO AFETADA PELO SUPRIMENTO DE FÓSFORO NO SOLO As respostas da senescência foliar ao suprimento de P podem constituir estratégias adaptativas para o crescimento vegetal sob condições limitantes do nutriente. O objetivo deste trabalho foi avaliar os efeitos do suprimento de P no solo na senescência foliar do feijoeiro (Phaseolus vulgaris L.). Oito doses de P, variando entre 5 e 640 mg kg -1 de P, foram aplicadas em vasos com 10 kg de Argissolo Óxico, onde foram crescidas quatro plantas da cultivar Carioca. As folhas presas às plantas foram contadas semanalmente; as folhas senescidas, coletadas em intervalos de dois dias; e as sementes colhidas na maturação. O número de folhas vivas aumentou até 48 dias após emergência (DAE) e decresceu após, independentemente da dose de P aplicada ao solo. Nas doses mais baixas de P, o aumento inicial e o decréscimo final do número de folhas foram pouco intensos, enquanto nas maiores doses desse nutriente o número de folhas aumentou intensamente no início e decresceu rapidamente após 48 DAE. A acumulação de massa seca e de P nas folhas senescentes aumentou com o acréscimo das doses de nutriente até 61 DAE; posteriormente, reduziram-se as diferenças entre as doses de P. As maiores quantidades de massa seca e de P depositadas pelas folhas senescentes foram observadas aos 48-54 DAE nas maiores doses de P; aos 62-68 DAE, nas doses intermediárias; e aos 69-76 DAE, nas menores doses. ...

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Phosphorus Nutrition Influence on Leaf Senescence in Soybean

Cited by 63 publications

References 23 publications

Phosphorus Nutrition Influence on Starch and Sucrose Accumulation, and Activities of ADP-Glucose Pyrophosphorylase and Sucrose-Phosphate Synthase during the Grain Filling Period in Soybean

Phosphorus Nutrition Influence on Starch and Sucrose Accumulation, and Activities of ADP-Glucose Pyrophosphorylase and Sucrose-Phosphate Synthase during the Grain Filling Period in Soybean

Photosynthesis, Rubisco Activity and Amount, and Their Regulation by Transcription in Senescing Soybean Leaves

Leaf senescence of common bean plants as affected by soil phosphorus supply

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