Abstract
Vascular bundles were isolated from grapefruit (Citrus paradisi Macf.) during periods of rapid sucrose translocation into fruit. Invertase and sucrose synthase activities were assayed in these strands and compared with immediately adjacent tissues (inner most peel and segment epidermis) and phloem-free juice sacs during four growing seasons. Although sucrose synthase was present in sink cells, the significantly greater activity in vascular strands (per unit fresh weight and protein) indicated that the role of this enzyme in translocation may include a vascular function in addition to its proposed involvement in metabolism of importing cells.
Full text
PDF
Images in this article
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Koch K. E., Avigne W. T. Postphloem, nonvascular transfer in citrus: kinetics, metabolism, and sugar gradients. Plant Physiol. 1990 Aug;93(4):1405–1416. doi: 10.1104/pp.93.4.1405. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Lowell C. A., Tomlinson P. T., Koch K. E. Sucrose-metabolizing enzymes in transport tissues and adjacent sink structures in developing citrus fruit. Plant Physiol. 1989 Aug;90(4):1394–1402. doi: 10.1104/pp.90.4.1394. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Maas C., Schaal S., Werr W. A feedback control element near the transcription start site of the maize Shrunken gene determines promoter activity. EMBO J. 1990 Nov;9(11):3447–3452. doi: 10.1002/j.1460-2075.1990.tb07552.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Sung S. J., Xu D. P., Black C. C. Identification of actively filling sucrose sinks. Plant Physiol. 1989 Apr;89(4):1117–1121. doi: 10.1104/pp.89.4.1117. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Yang N. S., Russell D. Maize sucrose synthase-1 promoter directs phloem cell-specific expression of Gus gene in transgenic tobacco plants. Proc Natl Acad Sci U S A. 1990 Jun;87(11):4144–4148. doi: 10.1073/pnas.87.11.4144. [DOI] [PMC free article] [PubMed] [Google Scholar]