Sugar unloading in roots of <i>Ricinus communis</i> L.

Chapleo, S.; Hall, J. L.

doi:10.1111/j.1469-8137.1989.tb00701.x

Cited by 8 publications

(1 citation statement)

References 21 publications

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“…In Ricinus roots, phloem unloading appears to be via a symplastic route (Chapleo and Hall 1989). The amino acid uptake process in Ricinus roots has been suggested to serve as a retrieval system for amino acids effiuxed from the phloem (Schobert and Komor 1987).…”

Section: Discussionmentioning

confidence: 99%

Characterization of solute/proton cotransport in plasma membrane vesicles from Ricinus cotyledons, and a comparison with other tissues

Williams

Nelson

Hall

1992

Planta

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Plasma membrane vesicles, purified by aqueous two-phase partitioning, were used to investigate the presence of sugar and amino acid carriers in cotyledons and roots of Ricinus communis L. and in roots of red beet (Beta vulgaris L.). Artificial pH and electrical gradients were generated across the plasma membrane, and [(14)C]acetate and [(14)C]tetraphenylphosphonium were used to demonstrate the presence of an internal alkaline pH gradient and an internal negative membrane potential, respectively. In Ricinus cotyledons, uptake of sucrose was more strongly inhibited than that of glutamine by p-chloromercuribenzenesulphonic acid, phlorizin and phenylglyoxal. The sucrose transport system showed a high degree of substrate specificity with only the presence of maltose and phenyl-α-glucoside significantly affecting sucrose uptake; in contrast, the glutamine transport system was inhibited by a number of other amino acids. ΔpH+gDψ-driven glutamine uptake showed saturation kinetics with a K m of 0.35 mol · m(-3). Sucrose and glutamine Δψ-driven uptake was pH dependent with an optimum in the acidic range (pH 6.25) and a decrease at higher pH values. Vesicles obtained from cotyledons and roots of Ricinus showed different transport properties. In the cotyledons, gDH+gDψ-driven transport for both sucrose and glutamine were observed at similar levels; however, in the root tissue, δpH-Δψ-driven glutamine transport was the dominant uptake process. Uptake rates for glucose and fructose were low in the cotyledons whereas, in the roots, glucose and sucrose transport were slightly higher than that of fructose. In vesicles from red beet tissue there was a different uptake profile, with evidence of proton-coupled cotransport systems for sucrose and glucose, but lower uptake of glutamine and fructose. The results are discussed in relation to the reported different pathways for loading and unloading of solutes in these tissues.

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Section: Discussionmentioning

confidence: 99%

Characterization of solute/proton cotransport in plasma membrane vesicles from Ricinus cotyledons, and a comparison with other tissues

Williams

Nelson

Hall

1992

Planta

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Development- and organ-specific expression of the genes for sucrose synthase and three isoenzymes of acid β-fructofuranosidase in carrot

Sturm

Sebková

Lorenz

et al. 1995

Planta

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Abstract. The steady-state levels of transcripts for cellwall 13-fructofuranosidase (cwl3F), for isoenzymes I and II of soluble acid 13-fructofuranosidase (sI, slI), and for sucrose synthase (ss) were determined in the sink and source organs of developing carrot (Daucus carota L.) plants. The expression patterns of the four genes clearly differed. The expression of the gene for cwl3F was development-specific but not organ-specific; high transcript levels were only found in plants with primary roots, with about equal amounts in leaf lamina, petioles and roots. The genes for sI and slI were mainly expressed in roots, sI predominating in primary roots and slI in developing tap roots. Transcripts for ss were found at a low level in all developing plant organs and were markedly up-regulated during the development of young leaves and during the transition of primary roots to tap roots. Developing tap roots contained only transcripts for slI and for ss. Marked alterations in the expression of these two genes after manipulation of the source/sink balance of these plants indicates their importance in sucrose partitioning. We suggest that ss regulates sucrose utilization in developing tap roots, whereas slI located in the vacuole controis sucrose storage and sugar composition.

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Expression profiles of genes related to carbohydrate metabolism provide new insights into carbohydrate accumulation in seeds and seedlings of Ricinus communis in response to temperature

Ribeiro

Ligterink

Hilhorst

2015

Plant Physiology and Biochemistry

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Sugar unloading in roots of Ricinus communis L.

Cited by 8 publications

References 21 publications

Characterization of solute/proton cotransport in plasma membrane vesicles from Ricinus cotyledons, and a comparison with other tissues

Characterization of solute/proton cotransport in plasma membrane vesicles from Ricinus cotyledons, and a comparison with other tissues

Development- and organ-specific expression of the genes for sucrose synthase and three isoenzymes of acid β-fructofuranosidase in carrot

Expression profiles of genes related to carbohydrate metabolism provide new insights into carbohydrate accumulation in seeds and seedlings of Ricinus communis in response to temperature

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