Understanding desiccation tolerance and sex-specific responses in Bryum argenteum: insights from phenological phases and physiological analyses.

BACKGROUND AND AIMS: Desiccation tolerance (DT) is crucial for survival in arid environments, where organisms develop strategies in reproduction, maintenance and defence 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 d 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 of Fv/Fm (quantum efficiency of photosystem II) and ϕPSII (effective quantum yield of photosystem II), while females demonstrated higher values and better recovery after desiccation. Protonemata also showed variation in Fv/Fm over time and with sex, with no significant differences in ϕPSII between them. Desiccated male shoots had higher mortality rates and produced fewer new shoots. For 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 the ecological responses of bryophytes to desiccation stress and provide insights into their adaptive strategies in challenging environments, such as the possible rarity of males in dioicous moss populations.

Beyond specimens: linking biological collections, functional ecology and biodiversity conservation / Más allá de los especímenes: uniendo colecciones biológicas, ecología funcional y conserva- ción de la biodiversidad

Several anthropogenic pressures are threatening biodiversity and may increase in the next years, altering eco- logical processes and ecosystem services. Biological collections offer a rich source of information to develop studies of functional ecology and biodiversity conservation. Key information related to morphology, physiology and life history could be obtained through functional traits provided by specimens in biological collections. Additionally, museum collections present a great potential for document changes of habitat disturbance, using response/effect framework, functional diversity measures, and fluctuating asymmetry approaches. Despite limitations of specimens in data such as abundance, imprecisions in specimen´s georeferencing, errors in taxonomic identification and the poor preservation state of some specimens, biological collections contain vast data banks, which could be useful in the contribution of key information for land use management and conservation planning.

Varias presiones antropogénicas amenazan la biodiversidad y pueden aumentar en los próximos años, alterando procesos ecológicos y servicios ecosistémicos. Las colecciones biológicas ofrecen una abundante fuente de información para desarrollar estudios de ecología funcional y conservación de la biodiversidad. Información clave relacionada con morfología, fisiología e historia de vida puede ser obtenida a través de los rasgos fun- cionales proporcionados por los ejemplares de colecciones biológicas. Adicionalmente, las colecciones de los museos presentan un gran potencial para documentar cambios en la perturbación del hábitat usando el marco de efecto/respuesta, las medidas de diversidad funcional, y el enfoque de asimetría fluctuante. A pesar de las limitaciones de los especímenes en datos como la abundancia, imprecisiones en la georreferenciación de los especímenes, errores en la identificación taxonómica y el mal estado de conservación de algunos ejemplares, las colecciones biológicas contienen enormes bancos de datos que podrían ser útiles en el aporte de información clave para el manejo del uso del suelo y los planes de conservación.