Reinvestigations of the Spindle Body and Related Problems I. Division of endosperm protoplasts of Zephyranthes in vivo and the isolation of the protoplast in vitro

• Published in: CYTOLOGIA Vol. 37; no. 1; pp. 131 - 142
• Main Authors: Niitsu, Tsuneyoshi, Hanaoka, Akiko
• Format: Journal Article
• Language: English
• Published: Japan Mendel Society, International Society of Cytology 1972
• ISSN: 0011-4545; 1348-7019
• DOI: 10.1508/cytologia.37.131

1. From the endosperm of Zephyranthes candida in an immature seed 1.7-2.7mm length, endosperm cells have been successfully isolated and cultured in vitro both in an artificial culture medium and also in endosperm fluid. 2. Histological analysis of the endosperm development investigated immediately after pollination revealed that each mitotic nucleus is embedded in its own protoplast without being enveloped in a cellulose cell wall. When the endosperm cavity is filled with naked protoplasts, the cellulose cell walls develop centripetally along the protoplast surface from the peripheral region to the central part of the seed tissue. 3. The behavior of chromosomes and spindles was investigated in the mitosis of isolated endosperm protoplasts which were freely suspended in vitro. From the result of in vivo observation on the continuous changes of mitosis in cultured protoplasts, it is confirmed that the spindle body is nuclear in origin and a system independent of the cytoplasm. This fact is also observed in fixed cells treated with modified Navashin's solution which is specific for the preservation of the atractoplasm, spindle substance and especially chromosomal fibers.