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Variability in the distribution of photoassimilates along leaves of temperate Gramineae

Authors

  • J. H. H. WILLIAMS,

    1. Ysgol Gwyddoniaeth Biolegol, Coleg Prifysgol Gogledd Cymru, Bangor, Gwynedd LL57 2UW, Wales, UK
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    • *

      Present address: Athrofa Gogledd Ddwryain Cymru, Plas Coch, Fford yr Wyddgrug, Wrescam, Clwyd LL11 2AW.

  • B. E. COLLIS,

    1. Environmental Biology Department, AFRC Institute for Grassland and Environmental Research, Welsh Plant Breeding Station, Plas Gogerddan, Aberystwyth SY23 3EB, Wales, UK
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    • Present address: Department of Botany, University of Glasgow, Glasgow G12 8QQ, Scotland, UK.

  • C. J. POLLOCK,

    1. Environmental Biology Department, AFRC Institute for Grassland and Environmental Research, Welsh Plant Breeding Station, Plas Gogerddan, Aberystwyth SY23 3EB, Wales, UK
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  • M. L. WILLIAMS,

    1. Ysgol Gwyddoniaeth Biolegol, Coleg Prifysgol Gogledd Cymru, Bangor, Gwynedd LL57 2UW, Wales, UK
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  • J. F. FARRAR

    1. Ysgol Gwyddoniaeth Biolegol, Coleg Prifysgol Gogledd Cymru, Bangor, Gwynedd LL57 2UW, Wales, UK
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  • Presented at the Second International Symposium on Fructan, Aberystwyth, UK, July 1992.

SUMMARY

Gradients of photoassimilates were determined at various positions along the length of mature leaves of wheat (Triticum aestivum L.) and Lolium temulentum L. Attached leaves showed greater accumulation in the tip region. This distribution was reversed in excised leaves illuminated uniformly on the adaxial surface. Internal transport of assimilate was detected both by sub-dividing excised leaves prior to illumination and by the administration of 14CO2 to the tips. The results are discussed in terms of the heterogeneity likely to occur in bulk extracts of leaf tissue and the ability of environmental perturbations to alter the balance of assimilates within leaves as well as their overall concentrations.

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