Abstract
The mechanisms of stabilization of cytoplasmic osmotic homeostasis in the bryophytes cells the participation of H + -ATPase and the intracellular ratio K + /Na + were investigated as one of the effective means of control over absorption and compartmentation of excess sodium ions in plant cells under salinity at the territory of the tailings storage facility of Stebnyk Mining and Chemical Enterprise “Polymineral” .Samples of Barb ula unguiculata Hedw., Didymodon rigidulus Hedw. and Brachythecium campestre (Müll. Hal.) Schimp. mosses were taken from 2 experimental plots in the territory of the tailings storage facility, which significantly differed in substrate salinity levels. The highest activity of ATPase was detected in B. unguiculata and D. rigidulus plants, which grew on the substrate with very high salinity level. This indicates an important role of the plasma membrane H + -pump in the adaptation of bryophytes to salt stress. In B. campestre shoots growing on the outskirts of the tailings storage with less salinity of the substrate, the enzymatic activity was found to be lower. It has been shown that the H + -ATPase activity depends on changes of the structural state of membranes induced by lipoperoxidation processes under stress conditions. The salt-tolerant B. unguiculata and D. rigidulus moss species have a lower content of TBA-active products, which positively affects on the functioning of membrane enzymes and leads to the development of general protective stress reaction. It has been shown that increasing of the H + -ATPase activity in moss cells under salinity conditions provides a removal of excess Na + ions to outside, that was confirmed by the results of our investigations of cellular localization of sodium. The sequential elution technique for determining cellular localization of cations developed for bryophytes by D. Brown and J. Walls (Brown, Wells, 1995) was used. It made possible to determine the ratio between the amount of sodium and potassium cations localized on the extracellular sites and in the intracellular matrix. In shoots of the studied moss species, a correlation between ATPase activity and the localization of sodium ions on the extracellular sites was found. This indicates an important role of H + -ATPase in eliminating of the excess cytotoxic sodium ions from moss cells under salt stress conditions. It was showed that potassium ions are important osmolytes in the bryophytes cells since under saline stress, an increase in content of potassium and K + /Na + correlation was observed in the intracellular matrix, which improves the plants tolerance to the influence of excess Na + ions. Keywords: moss, salinity, H + -ATPase, sodium and potassium content
Highlights
Today, nearly 6 % of the Earth’s surface is affected by salinization, so investigation of the processes of plant growth and development under the influence of increased salt concentrations is important for identifying salt-tolerant species that may be useful for further selection of salt-tolerant plants and soil phytoremediation
It was showed that potassium ions are important osmolytes in the bryophytes cells since under saline stress, an increase in content of potassium and K+/Na+ correlation was observed in the intracellular matrix, which improves the plants tolerance to the influence of excess Na+ ions
Bryophytes communities are presented by pioneer short-turf xeromesophytic moss species (Funaria hygrometrica Hedw., Didymodon rigidulus Hedw., D. fallax (Hedw.) Zander., Bryum caespiticium Hedw., Aloina ambigua (Bruch et Schimp.) Limpr., Barbula unguiculata Hedw. and Bryum pseudotriquetrum (Hedw.) P
Summary
Nearly 6 % of the Earth’s surface is affected by salinization, so investigation of the processes of plant growth and development under the influence of increased salt concentrations is important for identifying salt-tolerant species that may be useful for further selection of salt-tolerant plants and soil phytoremediation. Most terrestrial bryophytes adapted to water deficit, which obviously caused their tolerance to various osmotic stresses. First of all, this is ensured by the presence of high concentrations of osmolytes in moss cells [9; 12; 31]. It has been shown that under salinization conditions ion homeostasis in bryophytes cells was significantly dependent on the activity of H+-ATPase (PpSHP1 and PpSHP2) and Na+ATPase (PpENA1 and PpENA2) [31]. It was experimentally proved that at Physcomi trella patens (Hedw.) Bruch & Schimp the gene ENA1, which encodes Na+-ATPase (PpENA1), moss salt tolerance is increased in conditions of salt stress caused by 300 mM NaCl solution [18]. It has been shown that the bryophyte genes PpSHP1 and PpSHP2 encoding H+-ATRase have a high degree of homology to the yeast PMP3 gene and the RCI gene from Arabidopsis thaliana (L.) Heynh. [18]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
