Effect of Translocation-Hindering Procedures on Source Leaf Photosynthesis in Cucumber

Mayoral, Maria Luisa; Plaut, Z.; Reinhold, Leonora

doi:10.1104/pp.77.3.712

Cited by 34 publications

(30 citation statements)

References 28 publications

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“…In cucumber leaves, inhibition of photosynthesis was observed four days after removal of aerial sinks (Mayoral et al 1985) whereas in temperate gramineae net photosynthesis appears to remain substantially independent of sink activity for some time after experimental manipulation (Natr 1969. Reductions in net photosynthesis can be caused by stomatal closure (Setter & Brun 1980, and in this study stomatal conductance and transpirational loss were reduced as a result of sink manipulation.…”

Section: Discussionmentioning

confidence: 70%

Assimilate partitioning in leaves of the raffinose-storing herb Lamium album L.: the effects of altering source-sink balance

Kochhar

Rees

Pollock³

2003

Rev. bras. Bot.

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-(Assimilate partitioning in leaves of the raffinose-storing herb Lamium album L.: the effects of altering sourcesink balance). In Lamium album, sucrose and raffinose-family oligosaccharides are the major products of photosynthesis that are stored in leaves. Using gas analysis and 14 CO 2 feeding, we compared photosynthesis and the partitioning of recently-fixed carbon in plants where sink activity was lowered by excision of flowers and chilling of roots with those where sink activity was not modified. Reduction in sink activity led to a reduction in the maximum rate of photosynthesis, to retention of fixed carbon in source leaves and to the progressive accumulation of raffinose-family oligosaccharides. This ultimately affected the extractable activities of invertase and sucrose phosphate synthase. At the end of the light period, invertase activity was significantly higher in treated plants. By contrast sucrose phosphate synthase activity was significantly lower in treated plants. We propose that reducing sink activity in L. album is associated with a shift in metabolism away from starch and sucrose synthesis and towards sucrose catabolism, galactinol utilisation and the synthesis of raffinose-family oligosaccharides.Key words -Lamium album, oligosaccharides, source-sink interactions, starch, sucrose RESUMO -(Partição de assimilados em folhas de Lamium album L., uma planta herbácea que acumula rafinose: os efeitos da alteração do balanço fonte-dreno). Em Lamium album, sacarose e oligossacarídeos da família rafinósica (OFR) são os principais produtos da fotossíntese que são armazenados nas folhas. Utilizando análise de trocas gasosas e fornecimento de 14 CO 2 foram comparadas a fotossíntese e a partição de carbono recentemente fixado, em plantas nas quais a atividade dreno foi reduzida através da excisão das flores e resfriamento das raízes, com plantas nas quais a intensidade de dreno não foi modificada. A redução da atividade de dreno levou a uma diminuição na taxa máxima de fotossíntese, à retenção de carbono fixado nas folhas fonte e a um acúmulo progressivo dos OFR. Isso afetou as atividades extraíveis de invertase e sacarose fosfato sintase. Ao final do período de luz, a atividade de invertase foi significativamente maior nas plantas tratadas. Em contraste, a atividade de sacarose fosfato sintase foi significativamente menor nas plantas tratadas. Nós propomos que a redução da atividade de dreno em L. album esteja associada a uma alteração metabólica não relacionada ao metabolismo de síntese de amido e sacarose, mas sim ao catabolismo da sacarose, utilização de galactinol e síntese de OFR.Palavras-chave -amido, interações fonte-dreno, Lamium album, oligosacarídeos, sacarose 1.

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Section: Discussionmentioning

confidence: 70%

Assimilate partitioning in leaves of the raffinose-storing herb Lamium album L.: the effects of altering source-sink balance

Kochhar

Rees

Pollock³

2003

Rev. bras. Bot.

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“…One member of each group (cotton and bean, respectively) was studied in greater detail as reported below. The decrease in CO2 fixation rate could not be attributed to stomatal closure, as in the case of the short-term effect on photosynthesis outlined earlier ( 17), since no effect on stomatal resistance could be detected until the 8th d (Table II). Increasing the sink:source ratio produced no significant effects on the source leaf parameters measured, though there was a slight tendency toward a higher CO2 fixation rate and a lowered starch content.…”

Section: Resultsmentioning

confidence: 78%

“…The former comprised mainly sugars and amino acids, the latter mainly starch. Distribution of 14C among intermediates and end products of photosynthesis were determined by the calvin-Bassham method as described earlier (17). Sugars were analyzed in the combined ethanol and H20 extracts.…”

Section: After Emergence)mentioning

confidence: 99%

“…The assay was conducted sequentially with glucose 6-P dehydrogenase and P-glucose isomerase (13 (8) and x is that assayed by glucose oxidase. Starch was analyzed as outlined earlier (17).…”

Section: After Emergence)mentioning

confidence: 99%

“…We have been conducting an investigation into the effect of procedures which alter translocation rates on the metabolic activities of source leaves in several plant species grown under the same controlled environmental conditions. We recently reported (17) and involved changes in the relative amount of 14C incorporated into various photosynthetic products and intermediary compounds, but was not associated with stomatal responses. Herein we report on the long-term effects of sink metabolism in a number of other species and discuss the findings in relation to the possible nature of the signal transmitting sink demand to source activity.…”

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confidence: 99%

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Effect of Altered Sink: Source Ratio on Photosynthetic Metabolism of Source Leaves

Plaut¹,

Mayoral²,

Reinhold³

1987

Plant Physiol.

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ABSTRACrWhen seven crop species were grown under identical environmental conditions, decreased sink:source ratio led to a decreased photosynthetic rate within 1 to 3 days in Cucumis sativus L., Gossypium hirsutum L., and Rapwaaus sativus L, but not in Capsicum annuum L., Solanum melongena L., Phaseolus vulgaris L., or Ricinus communis L. The decrease was not associated with stomatal closure. In cotton and cucumber, sink removal led to an increase in starch and sugar content, in glucose 6-phosphate and fructose 6-phosphate pools, and in the proportion of '4C detected in sugar phosphates and UDPglucose following '4CO2 supply.When mannose was supplied to leaf discs to sequester cytoplasmic inoranic phosphate, promotion of starch synthesis, and inhibition of C02 fixation, were observed in control discs, but not in discs from treated plants. Phosphate (Ricinus communis L.) were grown in 2-L cylindrical plastic containers filled with vermiculite. Plants were thinned to one plant per pot shortly after emergence and irrigated twice a week with deionized water and once a week with half-strength Hoagland solution. Excess water and solution were drained through the bottom ofthe container. All species were grown in a chamber maintained at 25C, at a quantum flux density of 450 ,umol m-2 s-' (400-700 nm) and a 13 h/l l h light/dark photoperiod.Experiments with cotton were conducted about 10 d after the appearance of the first flower (11-12 weeks after emergence). Bean plants were used at the stage of the fully expanded first trifoliate leaf (22-25 d after emergence).One experiment with cotton ( Fig. 1) was conducted on field grown plants, Cotton was planted on May 25 in rows 1 m apart and thinned to 10 plants/m2 after emergence. Following light sprinkling to ensure emergence, a trickle irrigation system was installed. Laterals were located next to plant rows and emitters were 40 cm apart. The plants were irrigated once a day and the quantity of water supplied was based on evaporation from a Class A pan. Nutrients containing urea, H3PO4 and KCI at N:P:K ratio of 4:1:2 were predissolved in the irrigation water at a concentration of 80 g x m-3. Plants were used for this experiment on August 12, when there were about 10 bolls or flowers per plant.The sink removed in the case of the growth-chamber grown cotton was the developing first boll, and measurements were conducted on the mature leaf adjacent to this boll peduncle. In the field-grown cotton, various numbers of boils or flowers were removed, and measurements were conducted on four leaves of different ages along the plant axis. The extracts of these were combined. In the case ofbean plants, the sink removed included the young developing second trifoliate leaf and developing buds. The first trifoliate leaf was considered as the source leaf.CO2 fixation rate was measured in 1.5 cm2 circular areas of attached leaves according to a procedure described earlier (12).

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The Control of Photosynthetic Gas Exchange by Assimilate Accumulation in Wheat

Azcón-Bieto

1986

Biological Control of Photosynthesis

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Effect of Translocation-Hindering Procedures on Source Leaf Photosynthesis in Cucumber

Cited by 34 publications

References 28 publications

Assimilate partitioning in leaves of the raffinose-storing herb Lamium album L.: the effects of altering source-sink balance

Assimilate partitioning in leaves of the raffinose-storing herb Lamium album L.: the effects of altering source-sink balance

Effect of Altered Sink: Source Ratio on Photosynthetic Metabolism of Source Leaves

The Control of Photosynthetic Gas Exchange by Assimilate Accumulation in Wheat

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