The production of protonemal gemmae by mosses growing in deep shade

Whitehouse, H. L. K.

doi:10.1179/jbr.1980.11.1.133

Cited by 15 publications

(4 citation statements)

References 13 publications

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“…Ecological factors influencing gemmae production in terrestrial taxa range from high nutrient levels e.g Dicranoweisia cirrata (Duckett et al, 2001), light intensity e.g Schistostega pennata, Eucladium verticillatum, Gyroweisia tenuis and Didymodon trifarius (Whitehouse, 1980) to moisture e.g. Hyophila crenulata (Glime, 2007).…”

Section: Discussionmentioning

confidence: 99%

Asexual reproduction and protonemal developmentin vitroinFontinalis antipyreticaHedw.

Ares

Duckett

Pressel

2014

Journal of Bryology

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As sporophytes are very rare and asexual propagules unknown it is generally assumed that the moss Fontinalis antipyretica spreads almost exclusively via detached shoots carried in water currents. This study of regeneration in vitro reveals that F. antipyretica produces a variety of filament systems originating from virtually every part of the gametophyte, including: cortical cells in the bases of detached shoots, the margins and abaxial surfaces of leaves, stems following leaf removal and the laminae of detached leaves. The filaments vary from protonemata comprising short rectangular cells with transverse cross-walls to unbranched rhizoids. Filamentous gemmae, liberated by schizolysis, and spherical brood cells are produced in ageing and desiccating cultures. In nature these asexual propagules are probably produced in response to falling water levels and may have an important and hitherto unsuspected role in the spread and spatial genetic structure of F. antipyretica. In F. antipyretica the high level of phenotypic plasticity, that characterizes the mature gametophytes of aquatic bryophytes, also extends to the filamentous phase in the life cycle. Major differences between axenic and contaminated cultures are likely due to positive associations between the moss and bacterial and/or fungal contaminants.

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Section: Discussionmentioning

confidence: 99%

Asexual reproduction and protonemal developmentin vitroinFontinalis antipyreticaHedw.

Ares

Duckett

Pressel

2014

Journal of Bryology

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“…Although Whitehouse (1987) recorded the presence of filamentous protonemal gemmae alongside rhizoidal tubers in the many species of Bryum he grew in culture, and also recognized their likely importance in the life strategies of the genus, he did not undertake a systematic survey of their occurrence nor did he describe them in any great detail, with illustrations limited to those of Gyroweisia tenuis, Eucladium verticillatum and Barbula trifaria, all growing in deeply shaded habitats (Whitehouse, 1980). Indeed, in the 1966Indeed, in the , 1987Crundwell & Nyholm, 1964;Smith & Whitehouse, 1978) protonemal gemmae were generally ignored or overlooked despite having been clearly described and illustrated by Correns (1899).…”

Section: Introductionmentioning

confidence: 99%

Studies of protonemal morphogenesis in mosses. XI.Bryumand allied genera: a plethora of propagules

Pressel¹,

Matcham²,

Duckett³

2007

Journal of Bryology

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Asexual propagules found in the genus Bryum include rhizoidal and chloronemal tubers, axillary bulbils, chloronemal brood cells, and foliar and protonemal gemmae. While tubers and, to a lesser extent, axillary bulbils have been described in detail and used widely in the taxonomy of the genus, reports on the occurrence and morphology of protonemal gemmae are at best patchy, thus explaining their exclusion from any taxonomic and ecological evaluations of Bryum. Reported here is the first systematic survey of the occurrence of protonemal gemmae in 36 Bryum species and several related genera based on both wild and in vitro-grown specimens. Protonemal gemmae are described for the first time in 19 species; indeed the majority of Bryum species analysed produced protonemal gemmae in culture and subsequently these were also found in nature in many of the species. Compared with tubers (19 species) and bulbils (five species) protonemal gemmae (32 species) are the most ubiquitous asexual propagule in the genus. Overall gemma morphology within Bryum is fairly uniform: the gemmae are filamentous chloronemal derivatives and separate from the parent filament by the formation of a tmema (abscission) cell. Notable exceptions are the critically endangered B. schleicheri where clusters of apical choronemal branches detach by schizolysis and the highly branched gemmiferous protonemata of B. radiculosum which form from axillary rhizoids. While in the latter two species these unique gemma morphologies can be used for identification, overall protonemal gemmae are of much more limited use in Bryum taxonomy than rhizoidal tubers. Scanning electron microscopy, however, reveals that the protonemal gemmae in some species are highly ornamented, thus suggesting their possible future use in taxonomy alongside rhizoid papillosity. Although most of the genera allied to Bryum have vegetative propagules, very few produce protonemal gemmae. In those that do, only the gemmae of Mielichhoferia bryoides and Rhodobryum roseum have tmema cells and are remarkably similar to those of Bryum capillare and associated species. Gemma detachment in Epipterygium, Plagiomnium, Rhizomnium and Mnium is via schizolysis. Consideration of these gemma liberation mechanisms in relation to recent phylogenies of the Bryaceae suggests that schizolysis may be a synapomorphy for the Mniaceae. In vitro, gemma production is intrinsically linked to high nutrient availability in the substratum and there are indications that the same may also be true in nature. Ecologically, protonemal gemmae, presumably less long lived and less tolerant to desiccation than tubers, function in increasing the potential for initial establishment and localized spread of a given taxon, especially in situations where sporophytes are rarely produced.

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“…Gemma formation in some bryophytes is known to be similarly influenced by environmental conditions, such as humidity and light (Glime 2007). For example, Gyroweisia tenuis, Eucladium verticillatum, Schistostega pennata and Didymodon trifarius, which can grow in rock crevices, promote protonemal gemma production under low light conditions (Whitehouse 1980). It is thought that light-regulated gemma formation in these mosses is a strategy used to evade darker environments.…”

Section: Discussionmentioning

confidence: 99%

Regulation of gemma formation in the copper moss Scopelophila cataractae by environmental copper concentrations

Nomura

Hasezawa

2010

J Plant Res

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Considerable attention has recently been focused on the use of hyperaccumulator plants for the phytoremediation of soils contaminated with heavy metals. The moss, Scopelophila cataractae (Mitt.) Broth., is a typical hyperaccumulator that is usually observed only in copper-rich environments and which accumulates high concentrations of copper in its tissues. However, many of the physiological processes and mechanisms for metal hyperaccumulation in S. cataractae remain unknown. To address this issue, we examined the mechanisms regulating gemma formation, which is considered the main strategy by which S. cataractae relocates to new copper-rich areas. From this study we found that treatment of S. cataractae with high concentrations of copper suppressed gemma formation but promoted protonemal growth. The suppressive effect was not observed by treatment with heavy metals other than copper. These results suggest the importance of copper-sensitive asexual reproduction in the unique life strategy of the copper moss, S. cataractae.

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The production of protonemal gemmae by mosses growing in deep shade

Cited by 15 publications

References 13 publications

Asexual reproduction and protonemal developmentin vitroinFontinalis antipyreticaHedw.

Asexual reproduction and protonemal developmentin vitroinFontinalis antipyreticaHedw.

Studies of protonemal morphogenesis in mosses. XI.Bryumand allied genera: a plethora of propagules

Regulation of gemma formation in the copper moss Scopelophila cataractae by environmental copper concentrations

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