Regulation of Photosynthetic Carbon Metabolism in Cucumber by Light Intensity and Photosynthetic Period

Robbins, N. Suzanne; Pharr, D. M.

doi:10.1104/pp.85.2.592

Cited by 42 publications

(27 citation statements)

References 21 publications

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“…Huber, Rufty & Kerr (19846) found that under long days, in comparison with short days, the lower rate of starch accumulation in the leaf of soybean was associated with a greater sucrose phosphate synthase activity, higher leaf sucrose and a higher rate of photosynthate export. Sucrose phosphate synthase has also been implicated in the relation between daylength and starch storage in the leaf of cucumber (Robbins & Pharr, 1987), however in cucumber total radiation does not appear to be the only factor influencing the partitioning of photosynthate in the leaf. Britz, Hungerford & Lee (1985) have some evidence for Digitaria decumbens, based on studies using low intensity white light and far-red irradiation for daylength extension and night breaks, that there is at least a partial photoperiod control of assimilate partitioning into starch.…”

Section: {C) Vein Loading and Vascular Limitationsmentioning

confidence: 99%

Tansley Review No. 27 The control of carbon partitioning in plants

1990

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Summary This review reports on the processes associated with carbon transfer and metabolism in leaves and growing organs and the role of long‐distance transport and vascular links in the regulation of carbon partitioning in plants. Partitioning is clearly influenced by both the supply and demand for photosynthate and is moderated by vascular connections and the storage capacity of the leaves and pathway tissues. However there appears to be little more than circumstantial evidence either that short distance transfer of carbon within either the source or the sink, or that long‐distance transport in the phloem, are limiting photosynthesis or growth directly. Although individual biochemical and physiological processes relating to photosynthesis and growth may be well understood, the factors primarily responsible for the control of carbon partitioning in plants have not been clearly identified. There is a need for a greater understanding of organ initiation and development (source and sink formation and potential size), the clear identification of whether growth is sink or source limited (including possible sink‐controlled photosynthesis) and a detailed assessment of the role of storage in buffering developmental and environmental changes in sink and source activity. Also more information is needed on the role of hormonal and nutritional factors in regulating source and sink activity (organ interactions not directly associated with carbon transfer).

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Section: {C) Vein Loading and Vascular Limitationsmentioning

confidence: 99%

Tansley Review No. 27 The control of carbon partitioning in plants

1990

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“…Recently, a renewed interest has been shown in carbon partitioning in those species that, in addition to sucrose, also synthesize and export the raffinose oligosaccharide, stachyose. The biochemistry of carbon partitioning between phloem-mobile and storage metabolites is far more complicated in these plants because of the additional mechanisms that must be invoked to account for the diversion of carbon between sucrose and galactinol, the two major precursors of stachyose (5,13,16). In addition, however, there is increasing evidence that stachyose synthesis itself may be part of the phloem loading process in stachyose-translocating plants.…”

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confidence: 98%

Patterns of Assimilate Production and Translocation in Muskmelon (Cucumis melo L.)

Mitchell

Gadus²,

Madore³

1992

Plant Physiol.

122

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Continuous monitoring of steady-state carbon dioxide exchange rates in mature muskmelon (Cucumis melo L.) leaves showed diurnal patterns of photosynthesis and respiration that were translated into distinct patterns of accumulation and phloem export of soluble sugars and amino acids. Leaf soluble sugar patterns in general followed the pattern of photosynthetic activity observed in the leaf, whereas starch accumulated steadily throughout the light period. Sugar and starch levels declined through the dark phase. Phloem exudate analysis revealed that diurnal levels of the major transport sugars (stachyose and sucrose) in the phloem did not appear to correlate directly with the photosynthetic activity of the leaf but instead were inversely correlated with leaf starch accumulation and degradation. The amino acid pool in leaf tissues remained constant throughout the diurnal period; however, the relative contribution of individual amino acids to the total pool varied with the diurnal photosynthetic and respiratory activity of the leaf. In contrast, the phloem sap amino acid pool size was substantially larger in the light than in the dark, a result primarily due to enhanced export of glutamine, glutamate, and citrulline during the light period. The results indicate that the sugar and amino acid composition of cucurbit phloem sap is not constant but varies throughout the diurnal cycle in response to the metabolic activities of the source leaf.Rates of assimilate production in source leaves are determined both by biochemical regulation of key biosynthetic and degradative enzymes and by regulation of compartmentalization events that distribute assimilates between storage (chloroplast, vacuole) and transport (phloem) compartments (3,22). Export of photosynthetically fixed carbon from a source leaf is, therefore, dependent on the functioning of many complex metabolic events that control the production of phloem-mobile assimilates such as sucrose and delivery of these solutes to the phloem (3,6,18). In some plants, a direct correlation can be found between sucrose levels in the leaf and the rate of carbon export from the leaf, suggesting that the rate of phloem transport is controlled directly by the rate of sucrose synthesis (3,6,18 levels have no correlation with rates of export, suggesting possibly that it may not be the synthesis of sucrose but rather its delivery to the phloem system that is important in determining export rates (3,22). This may indicate a role for vacuolar transport processes in the control of export (3).At present, virtually all of our current information concerning biochemical regulation of carbon partitioning comes from plants that translocate sucrose exclusively (18). Recently, a renewed interest has been shown in carbon partitioning in those species that, in addition to sucrose, also synthesize and export the raffinose oligosaccharide, stachyose. The biochemistry of carbon partitioning between phloem-mobile and storage metabolites is far more complicated in these plants because of the additi...

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“…For other species the evidence is ambiguous. Although rates of E + I often fall with an increase in PAR-limitation (Chatterton & Silvius, 1979Robbins & Pharr, 1987), the reverse is sometimes true (Grange, 1985); and although rates of respiration tend to fall with decreasing PPFR (Givnish, 1988), they tend to increase with shorter day lengths/longer night lengths (Robinson, 1984;Grange, 1985; in complete contrast to A. moschatum; Table 2). …”

Section: Non-photosynthetic Responsesmentioning

confidence: 99%

Physiological responses of Atherosperma moschatum to day length, night length and photosynthetic photon fluence rate

Olesen

1995

New Phytologist

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SUMMARYYoung, non-reproductive plants of Atherosperma moschatum Labill. were conditioned to a range of day lengths, night lengths and photosynthetic photon fluence rates (PPFRs). The plants conditioned to the shorter of the two day lengths grew more slowly. On protein specific bases, the leaves of these plants had greater PPFR-saturated COj exchange rates (CERs), steeper initial slopes to the CER-PPF'R plots, and greater chlorophyll concentrations than did the leaves of the long day length plants. The rates of leaf respiration, and the rates of leaf carbon export and/or incorporation into structural leaf products (E-l-1) were similar under the two day lengths. The plants conditioned to the shorter of the two night lengths grew more quickly. The leaves of these plants had smaller PPFR-saturated CERs, shallower initial slopes to the CER-PPFR plots and smaller chlorophyll concentrations than did the leaves of the long night length plants, but greater rates of leaf respiration and E-l-1. In a separate experiment A. moschatum was shown to be vegetatively sensitive to night breaks of far-red irradiation. The plants conditioned to the higher of the two PPFRs grew more quickly. The leaves of these plants had greater PPFR-saturated CFRs, greater rates of leaf respiration, and greater rates of E+I than did the leaves of the lower PPFR plants, but shallower initial slopes to the CER-PPFR plots, and smaller chlorophyll concentrations. Acclimation to photosynthetic period (day length/night length) can be as marked as that to PPFR, and is quite different in character.

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Regulation of Photosynthetic Carbon Metabolism in Cucumber by Light Intensity and Photosynthetic Period

Cited by 42 publications

References 21 publications

Tansley Review No. 27 The control of carbon partitioning in plants

Tansley Review No. 27 The control of carbon partitioning in plants

Patterns of Assimilate Production and Translocation in Muskmelon (Cucumis melo L.)

Physiological responses of Atherosperma moschatum to day length, night length and photosynthetic photon fluence rate

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