The Effect of Sucrose and Other Factors on the Shoot‐root Ratio of Orchid Seedlings

Factors affecting the germination of orchid seeds

“…The germination of Vanilla planifolia seed was greatly improved following a tenfold reduction in nitrogen content of Knudson's B medium, bur was totally inhibited if concentrations were doubled (Lugo-Lugo 195 5a, b). Best growth and development of Epidendrmn nocturnum was recorded at 5 and 10 mM of NH 4 N0 3 (Yates and Curtis 1949).…”

“…Following the development of the fuse media for orchid seed germination (Knudson 1921(Knudson , 1922(Knudson , 1925(Knudson , 1946a) a considerable number of ocher media have been devised (la Garde 1929, Wynd 1933a, b, Burgeff 1936, Yates and Curtis 1949, Vacio and Went 1949a, Vacio 1950a, b, Sideris 1950, Kriechbaum 195 3, Withner 1959a, b, Kano 1965. Certain of these culture media are only slight modifications of Knudson's B or C ( 1922Knudson's B or C ( , 1946a) media whereas others include considerable changes and represent an effort to improve seed germination and seedling growth, especially in species which are difficult co germinate.…”

“…Optimum salt concentrations may vary with the species (Yates and Curtis 1949) and the same may be true of ionic ratios. Growth races of several orchids on some of the more common seed culture media show considerable variations.…”

“…Growth races of several orchids on some of the more common seed culture media show considerable variations. Various species show marked preferences regarding culture medium composition (Wynd 1933a, b, Withoer 1942, Breddy 1953) and improved growth on specially designed media may be due to these preferences (Knudson 1922, I.aGarde 1929, Burge.ff 1936, Yates and Curtis 1949, Vacin and Wene 1949a, Vacio 1950a, b, Sideris 1950, Liddell 1953a, b, Seeman 1953a, Kriechbaum 1953, Withner 1959a. Seeds of Vanilla planif olia, for example, germinated best on one tench the normal concentration of Knudson's solution B.…”

“…and 1000 p.p.m.) have caused marked chlorosis (Yates and Curtis 1949). Sodium hexamecapbospbate (Storey et aJ.…”