Phloem sap and leaf δ13C, carbohydrates, and amino acid concentrations in Eucalyptus globulus change systematically according to flooding and water deficit treatment

Merchant, Andrew; Peuke, Andreas D.; Keitel, Claudia; Macfarlane, Craig; Warren, Charles R.; Adams, Mark A.

doi:10.1093/jxb/erq045

Cited by 81 publications

(90 citation statements)

References 52 publications

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“…3B). We evaluated bud growth responses in intact plants by supplying a range of sucrose concentrations typically reported for phloem sap (25)(26)(27). All concentrations caused an early growth response, including 100 mM, which is at the low end of typical sucrose levels in phloem (Fig.…”

Section: Sucrose Supply Promotes Bud Release and Inhibits Branched1mentioning

confidence: 99%

Sugar demand, not auxin, is the initial regulator of apical dominance

Mason

Ross

Babst

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

481

510

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For almost a century the plant hormone auxin has been central to theories on apical dominance, whereby the growing shoot tip suppresses the growth of the axillary buds below. According to the classic model, the auxin indole-3-acetic acid is produced in the shoot tip and transported down the stem, where it inhibits bud growth. We report here that the initiation of bud growth after shoot tip loss cannot be dependent on apical auxin supply because we observe bud release up to 24 h before changes in auxin content in the adjacent stem. After the loss of the shoot tip, sugars are rapidly redistributed over large distances and accumulate in axillary buds within a timeframe that correlates with bud release. Moreover, artificially increasing sucrose levels in plants represses the expression of BRANCHED1 (BRC1), the key transcriptional regulator responsible for maintaining bud dormancy, and results in rapid bud release. An enhancement in sugar supply is both necessary and sufficient for suppressed buds to be released from apical dominance. Our data support a theory of apical dominance whereby the shoot tip's strong demand for sugars inhibits axillary bud outgrowth by limiting the amount of sugar translocated to those buds.shoot branching | sink demand | decapitation | girdling | long-distance signaling

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Section: Sucrose Supply Promotes Bud Release and Inhibits Branched1mentioning

confidence: 99%

Sugar demand, not auxin, is the initial regulator of apical dominance

Mason

Ross

Babst

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

481

510

View full text Add to dashboard Cite

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“…In addition, it is still a matter of debate if hexoses are transported in the phloem or not (van Bel and Hess, 2008;Liu et al, 2012). Phloem sugar composition can vary with environmental conditions, which could be one factor for changes in phloem δ 13 C (Merchant et al, 2010), independent of the original leaf-borne isotope signal, since δ 13 C differs between different carbohydrate molecules (Schmidt, 2003;Devaux et al, 2009). Compound-specific analysis, provided by modern LC-and GC-IRMS techniques (Sect.…”

Section: Chemical Composition Of Phloem Sugarsmentioning

confidence: 99%

Progress and challenges in using stable isotopes to trace plant carbon and water relations across scales

et al. 2012

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Abstract. Stable isotope analysis is a powerful tool for assessing plant carbon and water relations and their impact on biogeochemical processes at different scales. Our processbased understanding of stable isotope signals, as well as technological developments, has progressed significantly, opening new frontiers in ecological and interdisciplinary research. This has promoted the broad utilisation of carbon, oxygen and hydrogen isotope applications to gain insight into plant carbon and water cycling and their interaction with the atmosphere and pedosphere. Here, we highlight specific areas of recent progress and new research challenges in plant carbon and water relations, using selected examples covering scales from the leaf to the regional scale. Further, we discuss strengths and limitations of recent technological Published by Copernicus Publications on behalf of the European Geosciences Union. C. Werner et al.: Progress and challenges in using stable isotopesdevelopments and approaches and highlight new opportunities arising from unprecedented temporal and spatial resolution of stable isotope measurements.

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“…Differentiating xylem itself, is a sink tissue and its cells are entirely dependent on the import of reduced C from the photosynthetically active leaves via the phloem. Suc and amino acids, including Phe, are transported in the phloem and unloaded into wood-forming cells through specific transporters (Couturier et al, 2010;Merchant et al, 2010). Suc imported from the phloem can either be directly converted to cellulose or other cell wall carbohydrates through the activity of Suc synthase (Konishi et al, 2004).…”

Section: Suc May Be a Key Regulator Of Growth And Ligninmentioning

confidence: 99%