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FIELD AND CULTURE STUDIES ON GIGARTINA AGARDHII (RHODOPHYTA) 1 , 2
Author(s) -
West John A.,
Polanshek Alan R.,
Shevlin Dennis E.
Publication year - 1978
Publication title -
journal of phycology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.85
H-Index - 127
eISSN - 1529-8817
pISSN - 0022-3646
DOI - 10.1111/j.1529-8817.1978.tb02461.x
Subject(s) - biology , gametophyte , botany , ploidy , sporophyte , pollen , genetics , gene
Cultured carpospores from field‐collected plants of Gigartina agardhii Selfchell & Gardner gave rise to either Petrocelis‐ like crustose plants, or basal discs with erect Gigartina‐ like blades. Made tips excised from field‐collected female plants and cultured in the laboratory also showed two patterns of reproduction: procarpic papillae that only produced cystocarps in the presence of male plants with spermatid, or cystocarpic papillae that formed and released carpospores in the absence of male plants. The first pattern in each case above is evidence for a sexual life history and the second for an apomictic life history similar to that for G. papillata ( C. Agardh) J. Agardh. The resorcinol lest for k‐carrageenan was negative for Petrocelis ‐like plants and positive for foliose plants providing addition evidence that the former are haploid and the latter diploid as is characteristic for the Gigartinaceae. Crossing experiments between sexual male and female isolates of G. agardhii from several locations indicated that free interbreeding occurs. All crosses between G. agardhii and Gigartina‐ phase gametophytes cultured from tetraspores of Petrocelis middendorffii ( Ruprecht) Kjellman were negative demonstrating that G. agardhii is reproductively isolated from G. papillata/P. middendorffii and represents a distinct species. The tetrasporophytic phase of G . agardhii in nature is still not known. The significance of reproductive isolation in Gigartina subgenus Mastocarpus is discussed. On the bosis of nomenclatural priority G. agardhii Setchell & Gardner 1933 is placed in synonymy under G. jardinii J . Agardh 1876 .