Distribution and Transformation of Soluble Carbohydrates during Germination Growth of Sorghum1
- R. J. Newton2,5,
- D. A. Baltuskonis3,5,
- J. D. Goeschl3,5,
- D. H. Meckenstock4,5 and
- F. R. Miller4,5
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.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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