Water‐soluble carbohydrates of tropical pasture grasses and legumes

The soluble carbohydrate composition of the leaves and stems of 5 tropical grass species— Cenchrus ciliaris, Chloris gayana, Cynodon dactylon, Digitaria decumbens and Setaria sphacelata —and 5 tropical legume species— Desmodium intortum, Desmodium uncinatum, Glycine javanica, Phaseolus atropurpureus cv. Siratro and Stylosanthes humilis —has been studied at two stages of growth. Reducing sugars, total soluble sugars, fructosan, starch and pectin have been estimated. Chromatographic analysis of 80% ethanol extracts indicated the absence of the oligosaccharides, raffinose and stachyose, from the leaves and stems of the tropical grass species. They were present in the tropical legumes. None of the tropical grass or legume species were found to accumulate appreciable amounts of fructosan. The carbohydrate storage form in the grass species appeared to be sucrose, with starch of less importance. The carbohydrate storage forms in the legume species appeared to be sucrose, starch and pectin. The nature of the principal carbohydrate storage form appeared to be a characteristic of the species.