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Analysis of sugars in squash xylem sap
Hiroaki Iwai1, Masako Usui, Haruko Hoshino
1Institute of Biological Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8572 Japan.
Plant & Cell Physiology
|June 27, 2003
Summary
Xylem sap transports essential compounds like myo-inositol, oligosaccharides, arabinogalactan proteins (AGP), and pectins (RG-I, RG-II) from roots to shoots, facilitating plant communication.
Area of Science:
- Plant Physiology
- Plant Biochemistry
- Molecular Biology
Background:
- Xylem sap is crucial for root-to-shoot communication.
- Sugars within xylem sap play a significant role in plant physiological processes.
Purpose of the Study:
- To characterize the specific sugar compounds present in xylem sap.
- To elucidate the physiological functions of these sugars in plant development and signaling.
Main Methods:
- Xylem sap was collected and fractionated using 80% ethanol.
- Further purification involved cyclohexanediamine tetraacetate solubilization, anion exchange chromatography, and size exclusion chromatography.
- Compounds were identified using Yariv reagent and molecular mass determination.
Main Results:
- Xylem sap primarily contains myo-inositol and oligosaccharides in the ethanol-soluble fraction.
- Arabinogalactan proteins (AGP) were identified in the unbound fraction after anion exchange chromatography.
- Pectins, specifically rhamnogalacturonan (RG)-I and RG-II, were isolated and characterized by their molecular masses.
Conclusions:
- Xylem sap transports AGP, RG-I, RG-II, and oligosaccharides produced by root tissues to above-ground organs.
- These transported compounds are integral to root-to-shoot signaling pathways.
- Understanding xylem sap composition provides insights into plant growth regulation and stress responses.