New perspectives in the biophysics and physiology of bryophytes

Ellenberg N values of bryophytes in Central Europe*

“…In contrast to most vascular plants, bryophytes take up nutrients not only from the substrate but also directly from precipitation water as well as from airborne dust and aerosols (Frahm, 2001;Vanderpoorten and Goffinet, 2009). Therefore, uptake occurs, besides via mycorrhizal connections and the rhizoidosphere, by means of their complete gametophyte (and probably also sporophyte) surface (Raven et al, 1998;Frahm, 2001;Vanderpoorten and Goffinet, 2009). This way of nutrient uptake is promoted by a high extra-and intracellular cation exchange and ion-binding capacity (Smith, 1982;Daniels and Eddy, 1985;Frahm, 2001;Vanderpoorten and Goffinet, 2009).…”

A Non‐steady State Model Based on Dual Nitrogen and Oxygen Isotopes to Constrain Moss Nitrate Uptake and Reduction

“…Among terrestrial biota, mosses are believed to be sensitive and reliable indicators of atmospheric N loadings (Bragazza et al, 2005; Zechmeister et al, 2008). The major assumptions involved in this hypothesis include the following: (1) Most moss taxa lack stomata (at least in the gametophyte stage), with leaves only one cell thick and no cuticular barrier; (2) mosses lack efficient rooting and transport systems to take up nutrients from their growing substrates (Glime, 2007; Raven et al, 1998). Recently, moss‐tissue NO 3 − was measured to determine atmospheric NO 3 − pollution or its deposition levels (Liu, Koba, Liu et al, 2012; Liu, Koba, Takebayashi, et al, 2012), but they also assumed that mosses derive NO 3 − completely or mainly from atmospheric deposition.…”

“…In alpine sites in Scotland and China, 15 N tracers added to soils were recovered in terricolous mosses although the proportions were relatively low (2–9% in Ayres et al, 2006; 17–30% in Wang et al, 2014). Nitrate is highly mobile and soil‐NO 3 − may enter the moss cells by diffusion, potentially through cotransport with positively charged ions (Raven et al, 1998). However, quantifying the in situ contributions of NO 3 − derived from nitrification in soil substrates (soil‐NO 3 − ) and NO 3 − from atmospheric deposition (atm‐NO 3 − ) to the total NO 3 − influx into mosses is difficult (Figure 1).…”

“…Compared with the NRA assay, the natural isotopic abundances of NO 3 − in plant tissues provide an improved estimate of in situ NO 3 − reduction in wild terrestrial plants (Bloom et al, 2014; Liu et al, 2014, 2018; Yoneyama & Tanaka, 1999). Because mosses have relatively simple tissue structures (Raven et al, 1998), the entry of the source NO 3 − into moss cells may not have substantial isotopic effects (verified in phytoplanktons; Granger et al, 2004, 2010). In addition, excess N supply promotes NO 3 − efflux from the roots (Evans et al, 1996; Mariotti et al, 1982).…”

Organic nitrogen uptake is a significant contributor to nitrogen economy of subtropical epiphytic bryophytes

“…The preferences for ammonium (NH 4 + ) or amino acids over nitrate (NO 3 − ) have been observed in vascular plants when different N forms are supplied in equal doses 26 27 . Some researchers have suggested that bryophytes may not have a preference in N uptake because nutrients can enter moss tissues easily through cation exchange and the proton (H + ) pump (e.g., NH 4 + and amino acids) and through cotransport (e.g., NO 3 − ) for positively charged ions 10 15 28 . Other researchers have suggested that the uptake of NH 4 + should be higher than that of NO 3 −15 29 .…”