Supply and demand: sink regulation of sugar accumulation in sugarcane

A. J. McCormick*, D. A. Watt, M. D. Cramer

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Sugarcane (Saccharum spp. hybrids) accumulates sucrose to high concentrations and, as a result, has been the focus of extensive research into the biochemistry and physiology of sucrose accumulation. Despite this, the relationship between source leaf photosynthetic activity and sucrose accumulation in the culm sink is not well understood. The observations that photosynthetic activity declines during culm maturation in commercial cultivars and that high-sucrose-accumulating noble ancestral genotypes (Saccharum officinarum L.) photosynthesize at rates two-thirds of those of low-sucrose ancestors (Saccharum spontaneum L.) indicate that source-sink communication may play a pivotal role in determining sucrose yield. Although maturation of the culm results in a decreased demand for sucrose, recent evidence from partial leaf shading, defoliation, and transgenic studies indicates that sugarcane cultivars are capable of further increases in sugar content. Furthermore, sugarcane leaves appear to retain the capacity to increase the supply of assimilate to culm tissues under conditions of increased assimilate demand. The relationship between source and sink tissues in sugarcane should be viewed within a supply-demand paradigm; an often neglected conceptual approach in the study of this crop. Uncoupling of the signalling pathways that mediate negative feedback between source and sink tissues may result in improved leaf assimilation rates and, consequently, lead to increased sugarcane sucrose yields.

Original languageEnglish
Pages (from-to)357-364
Number of pages8
JournalJournal of Experimental Botany
Volume60
Issue number2
Early online date2 Dec 2008
DOIs
Publication statusPublished - Feb 2009

Keywords

  • Elasticity
  • metabolic regulation
  • photosynthesis
  • sucrose
  • TRANSGENIC TOBACCO PLANTS
  • SUCROSE ACCUMULATION
  • GENE-EXPRESSION
  • PHOTOSYNTHETIC RATES
  • ARABIDOPSIS-THALIANA
  • LEAF PHOTOSYNTHESIS
  • GLYCOLYTIC-ENZYMES
  • DOWN-REGULATION
  • MATURE LEAVES
  • CARBON FLUX

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