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Distribution and Transformation of Soluble Carbohydrates during Germination Growth of Sorghum

Newton, R. J., Baltuskonis, D. A., Goeschl, J. D., Meckenstock, D. H., Miller, F. R.
Crop science 1980 v.20 no.2 pp. 265-268
Sorghum bicolor, dhurrin, endosperm, fructose, germination, glucose, roots, seedlings, shoots, sucrose
Soluble components of sorghum (Sorghum bicolor (L.) Moench) seedlings growing in distilled water-sand media were quantified with gas-liquld-chromatography. In light, peak levels of soluble component accumulation occurred in the roots in 4 days, in the endosperm in 8 days, and in the shoots in 10 days. Sucrose (2 µg/mg) was the predominant component in the dry seed. In 4-day-old seedlings, glucose and fructose levels were 15 and 20 µg/mg, respectively, in both shoots and roots. At l0 days, dhurrin levels in the shoot were 35 to 40 µg/mg and comprised 51% of the total soluble component while glucose accounted for 21%. In the dark, dhurrin levels in 10-day-old shoots were 27% of the total solubles and glucose levels were 45%.. Dhurrin levels were highest in the coleoptile-shoot primordium region (90 µg/mg) and the upper, growing portion of the mesocotyl (28 µg/mg). Monosaccharide levels were highest in the upper, mesocotyl region with glucose at 74 µg/mg and fructose at 51 µg/mg. In 4-day-old scutella, sucrose to glucose ratios were greater than 3. Dhurrin and monosaccharide levels were reciprocally related; this indicated the precursor roles of both glucose and fructose in glycoside synthesis. The detection of a glycoside with gas-liquid-chromatography has several distinct advantanges over the traditional, enzymatic-colorimetric assay.