Identification and quantitative analysis of stage-specific carbohydrates in loblolly pine (Pinus taeda) zygotic embryo and female gametophyte tissues
Gerald S. Pullman (1, 2) and Mike Buchanan (3)
1. School of Biology and Institute of Paper Science and Technology, Georgia Institute of Technology, 500 10th Street N.W., Atlanta,
GA 30332-0620, USA / 2. Corresponding author () / 3. Institute of Paper Science and Technology, Georgia Institute of Technology, 500 10th Street N.W., Atlanta, GA 30332-0620,
USA / Received November 15, 2007; accepted February 5, 2008; published online May 1, 2008
Summary
Stage-specific analyses of starch and 18 sugars, including pentoses, hexoses, disaccharides, trisaccharides, oligosaccharides
and sugar alcohols, were made throughout seed development for zygotic embryo and female gametophyte (FG) tissues of loblolly
pine (Pinus taeda L.). Tissue was most often analyzed in triplicate from two open-pollinated families grown in different locations and sampled
in different years. Carbohydrates were analyzed by enzymatic assay, high performance liquid chromatography or gas chromatography/mass
spectrometry. For all carbohydrates quantified, peak concentrations were higher in embryo tissue than in FG tissue. Significant
changes in starch and sugar concentrations occurred over time, with both seed collections showing similar trends in temporal
changes. Although concentrations were not always similar, embryo and FG tissues generally showed similar patterns of change
in starch and sugar concentrations over time. Total starch concentration was highest during early seed development and decreased
as development progressed. The major sugars contributing to osmotic potential during early seed development were D-pinitol, sucrose, fructose and glucose. During mid-seed development, D-pinitol, sucrose, fructose, glucose, melibiose and raffinose provided major contributions to the osmotic environment. During
late seed development, sucrose, raffinose, melibiose, stachyose and fructose were the major contributors to osmotic potential.
These data suggest stage-specific media composition for each step in the somatic embryogenesis protocol.
