Influence of age and stage of development on the neutral carbohydrate components in root exudates from alfalfa plants grown in a gnotobiotic environment

Investigations were carried out by gas–liquid chromatography–mass spectrometry on the neutral carbohydrate fraction of root exudates from DuPuits alfalfa plants grown gnotobiotically for 16 weeks. Carbohydrates detected were arabinose, ribose, xylose, fructose, mannose, glucose, inositol, sucrose, and maltose. Three components were not identified. A general trend was observed of decreasing concentration of total neutral carbohydrates released with increasing plant age; however, two components increased with time. Based on milligrams of carbohydrate released per gram of dry weight of root tissue, all carbohydrates decreased with increased plant age. Flowering plants produced a significant increase in amounts of material released over samples from clipped plants. The results support the view that age and stage of development are significant influences on the qualitative and quantitative nature of plant root exudates.