Desiccation–rehydration measurements in bryophytes: current status and future insights

Abstract

Desiccation-rehydration experiments have been employed over the years to evaluate the desiccation tolerance of bryophytes (Bryophyta, Marchantiophyta and Anthocerotophyta). Researchers have applied a spectrum of protocols to induce desiccation and rehydrate plants after desiccation. Furthermore, a wide variety of techniques have been used to study desiccation-dependent changes in bryophyte molecular, cellular, physiological and structural traits, resulting in a multifaceted assortment of information that is challenging to synthesize. We analyzed 337 desiccation/rehydration studies providing information for 351 species to identify the most frequent methods used, analyze the advancements in desiccation studies over the years and characterize the taxonomic representation of the species assessed. The steady increase in the number of publications has been associated with the number of traits measured as new experimental techniques have been introduced. We observed certain similarities across methodologies, but nevertheless, the degree of convergence among the experimental protocols was surprisingly low. Thus, individual studies were largely unique, complicating comparative generalizations. Although the desiccation responses have been studied in detail in some model species, the overall taxonomic coverage of desiccation responses is poor. Out of 52 bryophyte orders, 40% have not been studied at all, and the data are lacking for multiple remote or difficult to access locations. We conclude that for quantitative interspecific comparisons of desiccation tolerance, rigorous standardization of experimental protocols and measurement techniques is needed. In addition, simultaneous use of an array of experimental techniques is required to gain a mechanistic insight into the relevance of different traits modified in response to desiccation and to assess the timing of different processes from molecular to whole plant level. For prediction of bryophyte community responses to current and future environmental stresses, new studies should also aim to fill gaps in taxonomic, ecological and spatial coverage of bryophytes.

Ecology explains anhydrobiotic performance across tardigrades, but the shared evolutionary history matters more

“…The quantification of different facets of fitness (including recovery from anhydrobiosis) has been shown to be far from easy, even in comprehensively studied groups such as bryophytes (e.g. Morales‐Sánchez et al., 2022). Anhydrobiotic recovery in tardigrades can be described by two components: the proportion of animals that survive desiccation ( p ) and the time it takes for them to recover after rehydration ( Q ).…”

“…hygrometers in moss cushions by Jang & Viles, 2022). Also, moss substrates could be classified based on species‐specific humidity preference databases (Morales‐Sánchez et al., 2022).…”

“…The ability to survive extreme abiotic stress is known as cryptobiosis (Arakawa, 2022; Clegg, 2001; Møbjerg et al., 2011; Møbjerg & Neves, 2021; Rebecchi et al., 2020), and one of its most widespread and studied forms is anhydrobiosis, the adaptation to environmental desiccation through a reversible state of suspended animation, found in many taxa, for example animals, fungi and plants (Guidetti et al., 2011; Kaczmarek et al., 2019; Morales‐Sánchez et al., 2022; Rebecchi et al., 2020; Wełnicz et al., 2011; Wiemken, 1990). Desiccated individuals can survive without liquid water even for years (Fontaneto et al., 2012; Grewal, 2000; Rebecchi et al., 2006; Roszkowska et al., 2020) after which, upon rehydration, they are able to resume normal metabolic activity.…”