Inorganic content in rice phloem sap

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Abstract
Mineral composition of riee phloem sap exuded from the cut end of insect stylets was analyzed by inductively coupled plasma emission spectroscopy (ICP). The most abundant cation of the sap was K and its concentration was about 5,900 ppm. The order of the concentration of the elements found was K>P, Na>S, Mg>Ca, Fe>An, Cu, Mn. The qualitative determination of orthophosphate of the sap by gas chromatography (GC) and gas chromatographic mass spectrometry (GC-MS) revealed that the sap contained 700–900 ppm of orthophosphate, suggesting that most of the phosphorus compounds consisted of orthophosphate. 32P-NMR spectrum of the phloem sap confirmed that the major phosphorus compound of the sap consisted of orthophosphate. No other phosphorus compounds were detected in these analyses. NH3-N was contained in the sap at a concentration of 12.8 mm.