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ULTRASTRUCTURAL STUDIES OF SPERMATOGENESIS IN THE ANTHOCEROTALES. II. THE BLEPHAROPLAST AND ANTERIOR MITOCHONDRION IN PHAEOCEROS LAEVIS: LATER DEVELOPMENT
Author(s) -
Carothers Zane B.,
Moser John W.,
Duckett Jeffrey G.
Publication year - 1977
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.1002/j.1537-2197.1977.tb10801.x
Subject(s) - biology , nucleus , anatomy , prophase , mitochondrion , ultrastructure , chromatin , microbiology and biotechnology , spermatogenesis , meiosis , dna , genetics , endocrinology , gene
Chromatin condensation begins as the multilayered structure (MLS) in Phaeoceros reaches its maximally structured differentiation. As nuclear elongation and chromatin condensation proceed, the S 2–4 strata disappear, and the nuclear beak extends between the S 1 and the nearly spherical anterior mitochondrion. In a mature sperm the mitochondrion is elongate and lies completely anterior to the blunt front end of the nucleus. The 12 S 1 tubules extend over the anterior mitochondrion and nucleus, but their number becomes reduced to five at the level where the nucleus' midportion is constricted. The anterior ends of the S 1 tubules lie embedded in a rather conical osmiophilic crest. Flagellar insertion is restricted to the extreme anterior tip of the S 1 tubules. The locomotory apparatus in Phaeoceros is compared with that of other bryophytes.