MICROSTRUCTURE AND COMPOSITION OF DIGITARIA-EXILIS STAPF (ACHA) - A POTENTIAL CROP

Microstructure of the mature caryopsis of Digitaria exilis Stapf was s tudied by light and scanning electron microscopy and compared to chemi cal composition. The general structure of the caryopsis was similar to that of other grains, notably the millets. Thin bracts (the palea and lemma) and two glumes encased the caryopsis which consists of the thi n, compressed layers of pericarp, testa, and cuticle surrounding the e ndosperm and embryonic tissues. The endosperm consisted of a single la yer of aleurone cells and the starchy endosperm. The aleurone layer wa s thin over most of the starchy endosperm and thicker at the junction of the embryo and starchy endosperm. Aleurone cells contained lipid dr oplets and protein bodies, The cell contents of the starchy endosperm consisted of simple, polyhedral starch granules, lipid droplets, and p rotein bodies. Protein bodies were more abundant toward the periphery, and diminished toward the central portion of the starchy endosperm. C ells in certain regions of the embryo contained few, small, spherical starch granules and an abundance of protein bodies. Protein bodies con taining phytic acid inclusions were located in the scutellum of the em bryo. Compositional analyses revealed that the grain contained 8.2% pr otein, 2.1% fat, 0.48% fiber, and 1.4% ash.