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APOMIXIS IN AMELANCHIER LAEVIS, SHADBUSH (ROSACEAE, MALOIDEAE)
Author(s) -
Campbell Christopher S.,
Greene Craig W.,
Neubauer Benedict F.,
Higgins Jean M.
Publication year - 1985
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.1537-2197.1985.tb08397.x
Subject(s) - biology , apomixis , ovule , botany , megaspore , meiosis , polyploid , clearance , parthenogenesis , differential interference contrast microscopy , ploidy , embryo , microbiology and biotechnology , medicine , pollen , biochemistry , physics , gene , microscopy , optics , urology
We studied ovule and megagametophyte development in tetraploid ( n = 34) individuals of Amelanchier laevis in Maine. Nomarski differential interference contrast microscopy of cleared, whole ovules and conventional microscopy of sectioned, stained material show no clear evidence for the successful completion of meiosis. Instead, the megasporocyte or its derivatives degenerate and one to six nearby cells develop into aposporous initials. Usually more than one of these divide to form eight‐nucleate, Polygonum ‐type megagametophytes. The egg apparently forms a proembryo parthenogenetically, but seed maturation requires pollination. This evidence for apospory and pseudogamy, the first to be reported in Amelanchier , conforms to the general pattern found in other apomictic genera of the Maloideae.