Regulation of Photosynthesis by End-Product Accumulation in Leaves of Plants Storing Starch, Sucrose, and Hexose Sugars

Goldschmidt, Eliezer E.; Huber, Steven C.

doi:10.1104/pp.99.4.1443

Cited by 392 publications

(273 citation statements)

References 19 publications

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“…Assimilate accumulation was observed throughout the photoperiod, suggesting that sucrose did not significantly inhibit its own synthesis. Goldschmidt & Huber (1992) observed the same in a range of starch-and sugar-storing species. RFO were also present; Kandler (1967) found these oligosaccharides as products of photosynthesis in a number of plants from the Lamiaceae The rate of photosynthesis was compared with the accumulation of the products of photosynthesis.…”

Section: Resultssupporting

confidence: 50%

Assimilate partitioning in leaves of the raffinose-storing herb Lamium album L.: photosynthesis and carbon partitioning throughout the photoperiod

Kochhar¹,

Rees²,

Pollock³

2003

Rev. bras. Bot.

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-(Assimilate partitioning in leaves of the raffinose-storing herb Lamium album L.: photosynthesis and carbon partitioning throughout the photoperiod). Lamium album accumulates starch, sucrose and raffinose-family oligosaccharides (RFO) as the major products of photosynthesis. These products were measured in leaves throughout a sixteen-hour photoperiod and under various irradiance conditions. There was continuous accumulation of sucrose and starch. The rate of gas exchange was higher at 500 µEm 2 s -1 and 900 µEm 2 s -1 than at 300 µEm 2 s -1 . The rate of photosynthesis did not decline over the sixteen-hour photoperiod, which suggested that there was no short-term feed back inhibition due to sucrose accumulation in this plant. When the products of photosynthesis were compared at the end of the photoperiod, only sucrose increased in abundance at high irradiance. The RFO pool in leaves was shown to contain raffinose, stachyose and verbascose; galactinol was also present. 14 CO 2 feeding demonstrated that roots and flowers were the major sinks. The middle leaves were major source leaves whilst young leaves acted as both sources and sinks.Key words -Lamium album, partitioning, raffinose family oligosaccharides, starch, sucrose RESUMO -(Partição de assimilados em folhas de Lamium album L., uma planta herbácea que acumula rafinose: fotossíntese e partição de carbono ao longo do fotoperíodo). Lamium album acumula amido, sacarose e oligossacarídeos da família rafinósica (OFR) como produtos principais da fotossíntese. Estes produtos foram medidos em folhas durante um fotoperíodo de 16 horas e sob várias condições de irradiância. Houve um acúmulo contínuo de sacarose e amido. As taxas de trocas gasosas foram maiores a 500 e 900 µEm -2 s -1 do que a 300 µEm -2 s -1 . A taxa de fotossíntese não declinou durante o fotoperíodo de 16 horas, o que sugere que não existe um mecanismo inibitório de retroalimentação de curto prazo devido ao acúmulo de sacarose nesta planta. Quando os produtos da fotossíntese foram comparados ao final do fotoperíodo, apenas a sacarose aumentou em abundância em alta irradiação. Os OFR foram analisados e são compostos por rafinose, estaquiose e verbascose; galactinol também esteve presente. O fornecimento de 14 CO 2 demonstrou que raízes e flores foram os principais drenos. As folhas do meio foram as principais fontes enquanto folhas jovens atuaram como fonte e dreno ao mesmo tempo.Palavras-chave -amido, Lamium album, oligossacarídeos da família rafinósica, partição, sacarose 1.

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Section: Resultssupporting

confidence: 50%

Assimilate partitioning in leaves of the raffinose-storing herb Lamium album L.: photosynthesis and carbon partitioning throughout the photoperiod

Kochhar¹,

Rees²,

Pollock³

2003

Rev. bras. Bot.

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“…In addition, environmental factors, such as elevated C02 (Stitt, 1991;Stitt et al, 1991;van Oosten et al, 1994;Nie To whom correspondence should be addressed at Department of Molecular Biology, Massachusetts General Hospital, Wellman 11 17, Boston, MA 021 14. et al, 1995), and intrinsic genetic variations, such as different invertase levels (Goldschmidt and Huber, 1992), have been proposed to affect photosynthetic capacity through sugar regulation. Although sugar signal transduction pathways are well characterized in prokaryotes (Saier et al, 1990(Saier et al, , 1995 and unicellular eukaryotes (Entian and Barnett, 1992;Gancedo, 1992;Johnston and Carlson, 1992;Trumbly, 1992;Ronne, 1995;Thevelein and Hohmann, 1995), relatively little is known about the molecular and biochemical mechanisms underlying sugar responses in multicellular eukaryotes, especially in sugar-producing higher plants.…”

Section: Introductionmentioning

confidence: 99%

Hexokinase as a sugar sensor in higher plants.

et al. 1997

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“…The reduced F PSII in vte2-1 after 14 d could result from feedback inhibition of photosynthesis attributable to the accumulation of downstream carbon metabolites (Goldschmidt and Huber, 1992;Koch, 1996;Paul and Foyer, 2001;Paul and Peliny, 2003). To assess this possibility, starch, glucose, fructose, and sucrose contents were analyzed during the time course of 7.58C treatment.…”

Section: Tocopherol-deficient Mutants Accumulate Carbohydrates Duringmentioning

confidence: 99%

Tocopherols Play a Crucial Role in Low-Temperature Adaptation and Phloem Loading in Arabidopsis

et al. 2006

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To test whether tocopherols (vitamin E) are essential in the protection against oxidative stress in plants, a series of Arabidopsis thaliana vitamin E (vte) biosynthetic mutants that accumulate different types and levels of tocopherols and pathway intermediates were analyzed under abiotic stress. Surprisingly subtle differences were observed between the tocopheroldeficient vte2 mutant and the wild type during high-light, salinity, and drought stresses. However, vte2, and to a lesser extent vte1, exhibited dramatic phenotypes under low temperature (i.e., increased anthocyanin levels and reduced growth and seed production). That these changes were independent of light level and occurred in the absence of photoinhibition or lipid peroxidation suggests that the mechanisms involved are independent of tocopherol functions in photoprotection. Compared with the wild type, vte1 and vte2 had reduced rates of photoassimilate export as early as 6 h into low-temperature treatment, increased soluble sugar levels by 60 h, and increased starch and reduced photosynthetic electron transport rate by 14 d. The rapid reduction in photoassimilate export in vte2 coincides with callose deposition exclusively in phloem parenchyma transfer cell walls adjacent to the companion cell/sieve element complex. Together, these results indicate that tocopherols have a more limited role in photoprotection than previously assumed but play crucial roles in low-temperature adaptation and phloem loading.

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Regulation of Photosynthesis by End-Product Accumulation in Leaves of Plants Storing Starch, Sucrose, and Hexose Sugars

Cited by 392 publications

References 19 publications

Assimilate partitioning in leaves of the raffinose-storing herb Lamium album L.: photosynthesis and carbon partitioning throughout the photoperiod

Assimilate partitioning in leaves of the raffinose-storing herb Lamium album L.: photosynthesis and carbon partitioning throughout the photoperiod

Hexokinase as a sugar sensor in higher plants.

Tocopherols Play a Crucial Role in Low-Temperature Adaptation and Phloem Loading in Arabidopsis

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