Cytotaxonomic Studies in the Ephemeraceae and Funariaceae

Bryan, Virginia S.

doi:10.2307/3240010

Cited by 7 publications

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“…n = 28" (Fig. 54) This species, which occurs abundantly as a weed, has been reported to have chromosome numbers of n = 14, 28 and 56, populations with n = 28 having been recorded from all over the world (Vaarama, 1955(Vaarama, , 1956Smith & Newton, 1967;Bryan, 1957; / FIGURES 51 to 61. Chromosome configuration in mosses.…”

Section: Grimmia Alpicohmentioning

confidence: 98%

Cytological studies on some mosses from the British Isles

Ramsay

1969

Botanical Journal of the Linnean Society

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The results of cytological investigations on 95 populations from 60 species of mosses are given. These results include studies of gametophyte mitoses from 26 of the species concerned. The technique for obtaining gametophyte mitotic preparations is described. Karyotype comparisons are made within the genera Polytrichum and Dicranum and the value of such comparisons is stressed. Where possible gametophytic mitotic observations have been correlated with sporo‐phytic meioses from the same gatherings.

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Section: Grimmia Alpicohmentioning

confidence: 98%

Cytological studies on some mosses from the British Isles

Ramsay

1969

Botanical Journal of the Linnean Society

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“…Although not very satisfactory, the mitotic divisions which have been observed in germinating spores support the:~conclusion that spores of the wild-type strain are uninucleate and have 14 chromosomes. Bryan (1957) found a diploid chromosome [Vol. 5.5 a Data are based on a single culture.…”

Section: Mutation Induction-spores and Protonemal Cells Were Irradiatmentioning

confidence: 99%

“…The present studies have established that culturing gametophytes of P. patens on minimal medium at 15-19 C induces the formation of antheridia and archegonia and readily results in the formation of capsules on 90-95 % of the gametophores in a culture. Reports (Whitehouse, personal communication; Andrews, 1918;Bryan, 1957) of the season when capsules were found on P. patens in nature suggested that sexual reproduction occurs during periods of relatively cool temperatures (15-20 C). Presumptive natural conditions with respect to temperature were simulated and cultures were allowed to mature at 15-19 C. Observation of cultures grown at 20-23 C and 15-19 C for 6 months established that sexual reproduction occurs only in those cultures kept at the lower temperature for 4-6 weeks.…”

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The Induction of Biochemical and Morphological Mutants in the Moss Physcomitrella Patens

Engel

1968

American J of Botany

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Physcomitrella patens is a monoecious, cleistocarpous moss which completes its life cycle under defined conditions in 7 to 8 weeks. Sexual reproduction is readily obtained by culturing gametophytes at 15 to 19 C. Mutants were induced by treatment of either spores or protonemal cells with ethyl methane sulfonate, N‐methyl‐N'‐nitro‐N‐nitrosoguanidine and X‐rays. Thiamine, para‐aminobenzoic acid, niacin and yeast extract auxotrophs were obtained. Growth response to various supplements was studied in the auxotrophic mutants. Five yellow mutants and two morphological mutants were induced. The chlorophyll content of the yellow mutants is reduced 35‐65% of wild type. The self‐sterile, para‐aminobenzoic acid‐dependent mutant was used as the archegonial parent in crosses with a yellow mutant and a morphological mutant. The self‐sterility of the para‐aminobenzoic acid‐requiring mutant appears to be pleiotropically related to the auxotrophic condition, since self‐sterility does not segregate from nutritional dependence in progeny of crosses. On the basis of tests with heterozygous diploids obtained by aposporous regeneration of capsule cells, two mutant alleles were shown to be recessive to their respective wild‐type alleles.

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“…The nature of these biological factors, however, is largely unknown. The moss Physcomitrella patens and its relatives have long been model systems for studies of hybrid interfertility (von Wettstein 1924; Bryan 1957). P. patens is now emerging as a model plant for comparative genomics, and studies including P. patens have provided insights into the evolution of land plant gene function and genome structure (Nishiyama et al 2003; Lang et al 2005; Rensing et al 2005; Stenoien 2005; Richardt et al 2007; Rensing et al 2008; reviewed in Quatrano et al 2007).…”

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THE SPECIATION HISTORY OF THEPHYSCOMITRIUM-PHYSCOMITRELLASPECIES COMPLEX

et al. 2010

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A central problem in evolutionary biology is identifying factors that promote the evolution of reproductive isolation. Among mosses, biogeographic evidence indicates that the potential for migration is great, suggesting that biological factors other than geographic isolation may be critical for speciation in this group. The moss Physcomitrella patens (Funariaceae) has long been used as a model for interspecies hybridization and has recently emerged as an important model system for comparative genomics. We report genealogical analyses of six loci from several populations of P. patens and related species in the genus Physcomitrium. These results unambiguously indicate that the so-called genus Physcomitrella arose at least three times from distinct ancestors within the genus Physcomitrium. In spite of the evidence for natural hybridization in the Physcomitrella-Physcomitrium complex, genealogical and experimental hybridization data indicate that the taxonomically defined species are reproductively isolated. However, these analyses suggest that Physcomitrium eurystomum was formed from a hybridization event between two early diverging lineages in the complex, and that the ancestral population size of these lineages was much smaller than the current population sizes. We discuss these findings in the context of the inferred mating system in the Physcomitrella-Physcomitrium complex and patterns of speciation and diversification.K E Y W O R D S : Bryophyte, Funariaceae, genealogical conflict, hybrid speciation, reproductive isolation, self-fertile.

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Cytotaxonomic Studies in the Ephemeraceae and Funariaceae

Cited by 7 publications

References 0 publications

Cytological studies on some mosses from the British Isles

Cytological studies on some mosses from the British Isles

The Induction of Biochemical and Morphological Mutants in the Moss Physcomitrella Patens

THE SPECIATION HISTORY OF THEPHYSCOMITRIUM-PHYSCOMITRELLASPECIES COMPLEX

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