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Grimmia pulvinata, Morchard Bishop, Devon, U.K. a. Cumulative frequency plot of ''moss-dry'' periods, June-August 1988, with fitted logistic curve. b. Fitted cumulative frequency curves for dry periods in successive 3-month intervals in 1989. Logarithmic scale on time axes.
Source publication
Desiccation-tolerance (DT), the ability to lose virtually all free intracellular water and then recover normal function upon rehydration, is one of the most remarkable features of bryophytes. The physiology of bryophytes differs in major respects from that of vascular plants by virtue of their smaller size; unlike vascular plants, the leafy shoots...
Contexts in source publication
Context 1
... Discrete ''pre- cipitation events'' averaged more than one a day for much of the year, but their frequency varied greatly. They outnumbered moss wet-dry cycles by a median factor of 3.29 (Fig. 2), because the moss often remained wet between bouts of precipitation. Indi- vidual ''moss dry'' periods followed a roughly log normal distribution (Fig. 3a). Logistic curves fitted to the data for successive three-month periods through 1989 are compared in Fig. 3b, and some parameters from the results are set out in Table ...
Context 2
... varied greatly. They outnumbered moss wet-dry cycles by a median factor of 3.29 (Fig. 2), because the moss often remained wet between bouts of precipitation. Indi- vidual ''moss dry'' periods followed a roughly log normal distribution (Fig. 3a). Logistic curves fitted to the data for successive three-month periods through 1989 are compared in Fig. 3b, and some parameters from the results are set out in Table ...
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Citations
... It may be suggested that the temperature and rainfall variables are responsible for the frequency of desiccation-tolerant mosses, and the reduced species diversity, although the latter also results from poor bryological exploration. In northwestern Mexico, and in Coahuila, several species occur that were identified as desiccation-tolerant, e.g., Crossidium crassinervium (Stark 2005), Syntrichia ruralis (Proctor et al. 2007) and Pseudocrossidium replicatum (Ríos et al. 2021). other possible adaptations may be shown by Aloina hamulus (growing on calcareous substrates), Grimmia laevigata, Jaffueliobryum wrightii, Ptychomitrium sinense (rock-inhabitants), but supporting research is still pendent. ...
The moss flora of the state of Coahuila and that in northwestern Mexico is poorly known. Recent exploration in the drylands of Coahuila have yielded findings that bring the number to about 101 species in the state moss flora where the Pottiaceae, Bryaceae, and Grimmiaceae are the families best represented. The lowland moss flora is well represented in the Chihuahuan Desert area in northern Mexico, but also in the southern United States. Species of Crossidium, Pseudocrossidium, and Syntrichia are known desiccation-tolerant mosses; Entodon concinnus and Ephemerum coherens are additions to the moss flora of Mexico.
... These two response forms are strategies observed in various life stages of plants, given that organisms display DT at different stages of their life. For instance, bryophytes are known for exhibiting DT in all life stages (Oliver et al., 2000;Oliver, 2005;Stark et al., 2022): from the protonema stage, where spores or vegetative propagules germinate and form protonemata (Pressel and Duckett, 2010;Greenwood et al., 2019), to the initial development of the gametophyte, and through later stages such as the mature gametophyte (Greenwood et al., 2019), gametes (Shortlidge et al., 2012;Stark et al., 2016), spores (Proctor et al., 2007), vegetative propagules (Greenwood et al., 2019) and sporophytes (Stark and Brinda, 2015). ...
Background and Aims
Desiccation tolerance (DT) is crucial for survival in arid environments, where organisms develop strategies in reproduction, maintenance, and defense to cope with water scarcity. Therefore, investigating the relationship between reproduction and DT is essential to understand the ecology and adaptive strategies of species. This study explores the connection between the development of male and female gametangia in the moss Bryum argenteum and the decrease in DT during the progression of phenological phases in gametangia and protonema.
Methods
Samples collected from a dry tropical forest in Brazil were cultivated, cloned, and subjected to desiccation. Subsequently, the physiological parameters of shoots and protonemata were analysed. Shoot and protonema regeneration were monitored for 28 days after the physiological analyses. Both phases were subjected to control and desiccation treatments.
Key Results
Significant effects of desiccation and sex on the physiological parameters and regeneration capacity of shoots and protonemata were found. Male shoots generally exhibited lower values in Fv/Fm, and ϕPSII, while females demonstrated higher values and better recovery after desiccation. Protonemata also showed variation in Fv/Fm over time and sex, with no significant differences in ϕPSII between them. Desiccated male shoots had higher mortality rates and produced fewer new shoots. Regarding the females, the regeneration patterns varied between the desiccation-exposed groups and the control, with decreased shoot production, and some protonemata growing into filaments without forming shoots.
Conclusion
These findings improve our understanding of bryophytes ecological responses to desiccation stress and provide insights into their adaptive strategies in challenging environments, such as the possible rarity of males in dioicous mosses populations.
... Lichens and bryophytes are often given as examples of organisms that have a desiccation tolerance. They are both all poikilohydric, which is defined as meaning that their water content (WC, thallus water content) will tend to equilibrium with the water status of their environment (Proctor et al., 2007;Stapper and John, 2015). However, opinions about the tolerance in lichens are ambiguous (Green et al., 2011). ...
... Most species are poikilohydric, i.e., they lack a conductive system to transport water and assimilates and therefore depend on water availability in their environment (Goffinet and Shaw, 2009;Brodribb et al., 2020). As a result, many species are desiccation-tolerant and can withstand extreme stresses when desiccated (Proctor et al., 2007;Stark, 2017). All these characteristics allow them to inhabit places where vascular plants often cannot grow such as bare rock surfaces or the bark of trees. ...
Extinction risk is not randomly distributed among species but depends on species traits, their relationship to climate and land use, and corresponding threats by global change. While knowledge of which factors influence extinction risk is increasingly available for some taxonomic groups, this is still largely lacking for bryophytes. Here, we used random forest models to study which biological and ecological traits and bioclimatic variables are important predictors for extinction risk in European bryophytes. We hypothesized that species with a high extinction risk have a short life span, low dispersal capacities, and are more likely specialists than generalists in terms of ecological traits and bioclimate. Overall, we found bioclimatic variables to be the most important predictors for extinction risk, most notably precipitation seasonality, and related ecological traits such as con-tinentality and elevational range. Important biological traits were plant size, life strategy and sporophyte production. In general, species living at climatic extremes and/or those with a narrow environmental range are more likely to be threatened. In addition, small-sized species and/or species with low reproductive effort and/or larger spore size are more likely to be threatened. Our findings imply that climate change may become an important driver of bryophytes extinction risk and that biological and ecological traits will be most relevant for species in coping with future threats.
... Leafy liverworts and pleurocarpous mosses are globally better adapted to shaded and humid environments [27]. In contrast, thalloid liverworts and acrocarpous mosses typically exhibit broader ecological requirements, thriving in sunnier, drier, and more xeric habitats [27,28]. ...
The aim of the present study is to update the list of bryophytes in the Cape Verde archipelago, with a focus on its distinctive terrestrial biota. The research was carried out through a combination of herbarium collections revision and fieldwork conducted from 2016 to 2019. The revised list includes 185 bryophyte taxa (175 species, 5 subspecies, and 5 varieties) from 93 genera and 42 families. Notably, 8 taxa are endemic, and the inclusion of 35 new taxa further enriches the bryophyte diversity of the archipelago. The distribution of bryophyte taxa varies across islands, with Santo Antão, São Nicolau, and Fogo exhibiting particularly high diversity. Acrocarpous mosses are the most common growth form (58.4%), followed by pleurocarpous mosses, thalloid liverworts (15.1% each), and leafy liverworts (11.4%). In conclusion, this study provides valuable insights into the bryophyte diversity of southern Macaronesia enhancing our understanding of its unique flora and emphasizing the imperative need for conservation efforts.
... In such conditions, bryophytes have adapted to rely on asexual reproduction as a survival strategy. Certain asexual structures exhibit desiccation tolerance (Proctor et al., 2007;Stark et al., 2016;Stark et al., 2017), contributing to the establishment of local bryophyte colonies (Kimmerer, 1994;Maciel-Silva, 2017). Additionally, while spores are typically considered the primary drivers of long-distance dispersal in bryophytes, some studies highlight the role of asexual structures in shaping species distribution on larger scales (Laenen et al., 2016;Lewis et al., 2014;Parsons et al., 2007;Pohjamo et al., 2006). ...
... In fact, the species number of bryophytes is the second highest among land plants [1]. The unique morphological structure and physiological characteristics of bryophytes enable them to survive in extremely arid and cold environments [2][3][4]. In alpine ecosystems, bryophytes play important roles in soil water retention [5,6], sand fixation [7], and frozen soil protection [8]. ...
... All of them were mosses. The largest family (i.e., species number > 10) was Pottiaceae (14 genera, 50 taxa), followed by Bryaceae (3,26) and Brachytheciaceae (2,12), accounting for 59.1% of the total number of taxa (Figure 2a). The most species-rich genus was Bryum (23 taxa), followed by Didymodon (14) and Brachythecium (11, Figure 2b). ...
... Compared to Diversity 2024, 16, 143 8 of 13 AM, turfs increased by 13.7% in AS, while wefts sharply decreased (16.8% vs. 5.6%) and mats disappeared. Cushions (3,5.6%) increased to as many as the wefts in AS. ...
The species number of bryophytes is the second highest among land plants. Alpine grasslands on the Qinghai–Tibet Plateau (QTP) are the largest among global alpine biomes. However, bryophyte flora in alpine grasslands on the QTP remains poorly explored relative to its large geographic extent. A total of 347 plots were surveyed across the QTP, and 149 bryophyte taxa in 24 families and 49 genera were recorded in alpine grasslands. The largest family was Pottiaceae, followed by Bryaceae and Brachytheciaceae. The most species-rich genus was Bryum, followed by Didymodon and Brachythecium. The dominant species were Didymodon tectorus, Didymodon fallax, Bryum caespiticium, Didymodon constrictus, and Didymodon ditrichoides. The Jaccard similarity indexes of bryophyte compositions between alpine meadow and alpine steppe at the family, genus, and species levels were 0.375, 0.367, and 0.282, respectively. Turf was the most common life-form (75.2%), followed by weft (16.1%) and cushion (5.4%). Endemic species to China accounted for 8.05% of the total taxa. Bryophyte diversity in alpine grasslands on the QTP is exceptional and irreplaceable. The changes in species composition and life-forms between different grassland types reflect the adaptations of bryophytes to harsh environments.
... Firstly, solar radiation directly affects the efficiency of photosynthesis in mosses, thereby influencing their growth rate and biomass accumulation [36,37]. Secondly, changes in solar radiation can affect the evaporation of moisture in mosses, further impacting their survival and reproductive capabilities [38]. Globally, similar studies have also identified the impact of solar radiation on moss diversity. ...
In the realms of ecology and biogeography, the interaction between biodiversity and environmental factors is a critical area of research. This intersection highlights how biological communities, especially among groups like bryophytes, are influenced and shaped by their surrounding environmental conditions. This study presents a pioneering investigation into the diversity and community structure of mosses in Qinhuangdao, Hubei Province, China, a region marked by its diverse topography and climate. Employing extensive field surveys across 30 plots, we gathered and analyzed the relationship between moss species distribution and environmental variables, including topographical, climatic, and soil factors. Utilizing a range of analytical techniques, such as cluster analysis, canonical correspondence analysis (CCA), and partial least squares path modeling (PLS-PM), we characterized the intricate relationships between moss biodiversity and environmental gradients. The research has documented 84 species distributed among 36 genera and 13 families. Solar radiation has a great impact on moss diversity. There were significant differences between Form. Entodon compressus and Form. Plagiobryum demissum. Climate has a great impact on the community structure of mosses. Geographical factors were also identified as key secondary influences, affecting moss community structures both directly and indirectly by creating suitable microenvironments and influencing climate and soil properties. Additionally, the study highlights the indirect impact of spatial factors on these environmental variables, which in turn shape the structure of biological communities. The findings indicate that the annual temperature range is a key factor influencing the distribution and formation of moss community structures. The findings provide new insights into the ecological adaptation of mosses in diverse environmental settings and lay a crucial foundation for biodiversity conservation and ecosystem management in the Qinhuangdao area.
... Due to its high water-holding capacity, callose can add to the plasticity in cell walls during the stress associated with cycles of desiccation and rehydration (Herburger and Holzinger, 2015). This follows the current understanding that desiccation tolerance in bryophytes is by means of 'constitutive' protective substances (Proctor et al., 2007). Other abiotic stresses, including mechanical stress and toxic metal exposure, have been correlated with increased callose deposition in the moss cell wall (Scherp et al., 2001;Tang, 2007;Krzesłowska et al., 2010;Krzesłowska, 2011). ...
Introduction
Leptoids, the food-conducting cells of polytrichaceous mosses, share key structural features with sieve elements in tracheophytes, including an elongated shape with oblique end walls containing modified plasmodesmata or pores. In tracheophytes, callose is instrumental in developing the pores in sieve elements that enable efficient photoassimilate transport. Aside from a few studies using aniline blue fluorescence that yielded confusing results, little is known about callose in moss leptoids.
Methods
Callose location and abundance during the development of leptoid cell walls was investigated in the moss Polytrichum commune using aniline blue fluorescence and quantitative immunogold labeling (label density) in the transmission electron microscope. To evaluate changes during abiotic stress, callose abundance in leptoids of hydrated plants was compared to plants dried for 14 days under field conditions. A bioinformatic study to assess the evolution of callose within and across bryophytes was conducted using callose synthase (CalS) genes from 46 bryophytes (24 mosses, 15 liverworts, and 7 hornworts) and one representative each of five tracheophyte groups.
Results
Callose abundance increases around plasmodesmata from meristematic cells to end walls in mature leptoids. Controlled drying resulted in a significant increase in label density around plasmodesmata and pores over counts in hydrated plants. Phylogenetic analysis of the CalS protein family recovered main clades (A, B, and C). Different from tracheophytes, where the greatest diversity of homologs is found in clade A, the majority of gene duplication in bryophytes is in clade B.
Discussion
This work identifies callose as a crucial cell wall polymer around plasmodesmata from their inception to functioning in leptoids, and during water stress similar to sieve elements of tracheophytes. Among bryophytes, mosses exhibit the greatest number of multiple duplication events, while only two duplications are revealed in hornwort and none in liverworts. The absence in bryophytes of the CalS 7 gene that is essential for sieve pore development in angiosperms, reveals that a different gene is responsible for synthesizing the callose associated with leptoids in mosses.
... Liverworts are plants with the gametophyte (n) as the dominant phase of the life cycle and, in general, are ectohydric, meaning that they absorb and transport water over their entire external body surface and lack specialized systems to regulate water loss, culminating in high sensitivity to micro-environmental changes (Proctor et al. 2007). Even their evolutionary history is linked to water relations: two major lineages (Porellales and Jungermanniales) are split based on the presence / absence of a water sac or lobule (lobule: 'a smaller segment of the unequally divided leaf in leafy liverworts, typically forming a small pouch' -Glime and Chavoutier 2017) that help to hold water in capillary spaces (Glime 2021). ...
... Building on this knowledge, we hypothesized that patterns in ITV respond to local environmental filtering resulting in: (1) significant differences in key morphological traits (lobe area, lobule area and underleaf area, ratio between lobule and lobe areas, ratio between number of laminate and total lobules, and stem width) among populations and higher ITV among than within populations; (2) significant trait covariation among populations; and (3) changes in morphological traits along elevation, light intensity and water availability gradients. Considering the direct relationship between water availability and the size and ecophysiology of liverworts (Proctor et al. 2007), we expect to observe a decrease in the size of the morphological traits studied in F. ericoides in habitats with lower water availability, higher luminosity and lower elevations, with the exception of leaf lobule area, which is expected to increase in order to enhance water storage and / or transport. In turn, in habitats with higher water availability, lower luminosity and higher elevations, we expect a greater magnitude of all the morphological traits studied except leaf lobule area. ...
... In the latter trait, laminate lobules were used instead of saccate lobules because their occurrence is considered an indicator of the humidity of the environment (Sim-Sim 1999). All traits were considered related to water uptake / retention, including area and width measurements, because in bryophytes, the growth of gametophytic structures is usually promoted by water availability (Proctor et al. 2007). The rarity of sporophytes in the populations precluded the inclusion of sporophytic traits in the analyses. ...
Understanding trait variation along environmental gradients is crucial for assessing the adaptive potential of species. We analysed the intraspecific variation in six morphological traits of Frullania ericoides across environmental gradients (elevation, canopy openness and distance to water sources) in a humid ecological refuge in Brazil’s semi-arid region. The traits measured (mean and coefficient of variation) were: leaf lobe area, leaf lobule area, underleaf area, stem width, ratio between leaf lobule area and leaf lobe area, and ratio between the number of laminate lobules and the total number of lobules. Seventy specimens from eleven localities (populations) showed greater intrapopulation than interpopulation mean trait variation. All traits, except for the ratio between leaf lobule area and leaf lobe area, presented interpopulation differences. Two trait strategies emerged: one related to water storage and plant size, and the other linked to proportional increases in leaf lobule area and lobe area. The lower the elevation was, the higher were the mean values of leaf lobe area and leaf lobule area, and the variance of stem width. The species exhibited significant trait variation, which can be decisive in the responses of populations to new selective pressures of establishment and maintenance.
