Several aspects of growth, development and sapogenin yield of tubers ofdioscorea spiculiflora

Tubers ofDioscorea spiculiflora and some characteristics of their growth are described. Original weights of tuber pieces were directly correlated to subsequent tuber growth and to numbers of nodes and leaves produced. Plants grown in peat rarely exhibited nutritional deficiency but responded to regular applications of fertilizer by great increases in shoot and tuber growth. Snpogenin analyses of tubers revealed (a) considerably higher content of sapogenins in original tuber pieces dug in Mexico than in one-and two-year-old tuber tissue developed subsequently from these pieces grown in peat in the greenhouse at Glenn Dale, Md.; (b) higher sapogenin content in the outer 1–11/2 mm layer of tubers than in the inner tissue; (e) no significant difference in sapogenin content of tissue from ventral and dorsal sides of tubers; and (d) no significant difference in sapogenin content of tubers front pistillate and staminate plants.