The Embryo Sac Sesamum and Formation and the Embryogeny of indicum L, in the Diploid the Tetraploid Strains

The gametogenesis and the embryogeny of Sesamum indicum L. were reported by Nohara (1934). He observed the embryo sac formation but did not completed the study up to the stage of the embryo. However,. Johansen (1950) states that the embryogeny of the Pedaliaceae probably follows the Onagrad type, judging from the inadequate illustrations accompanied by the rather meager accounts of the embryogeny of Sesamum orientale, Martynia louisiana and Pedalium murex. The present study was undertaken to complete the embryology of S. indicum L., and the author attempted to compare the tetraploid strain induced by colchicine with the diploid with respect to the embryogeny. Materials for the present study were collected from the developing ovules from the young-bud stage to the mature-seed stage. For investigating the development of the embryo, the flowers were castrated on the last evening previous to flowering and were artificially pollinated in the morning. After the artificial pollination, fixations were made at intervals as follows : 4, 8, 14, 20, 24, 30, 45, 48 and 72 hours, and 4, 5, 6, 7, 8, 10, 11 and 12 days after the pollination. The Navashin's solution was used for the observation of the embryo sac, and the Bouin's for the embryo. Transverse and longitudinal sections cut 8-15 thick were stained with Heidenhain's or Delafield's haematoxylin.