Maturation of Sweetgum and American Sycamore Seeds

Abstract Over three consecutive years in central Mississippi, sweetgum ( Liquidambar styraciflua L.) and sycamore ( Platanus occidentalis L.) fruits had nearly reached full-size by late June. Sweetgum seeds were physiologically mature by mid-August, but dry weight increased until late September. As sweetgum seeds matured, the crude fat level rose to 27 percent of seed dry weight. During maturation, concentrations of soluble nitrogen, soluble carbohydrates, and magnesium decreased, while those of protein nitrogen and phosphorus increased. Sycamore seeds became physiologically mature by early September. Chemical changes in sycamore were similar to those in sweetgum, except that the major food reserves were carbohydrates and not fats. Forest Sci. 18:223-231.