RESUMO
Understanding the effect of soil salinity on the diversity and species distribution of plant communities in inland salt marsh ecosystems could provide solutions for the management of regional saline soils and the protection of salt marsh wetland vegetation. A field experiment in succulent halophyte, Carex, and gramineous grass habitats in Ordos, Inner Mongolia (northwest China) was conducted to study the diversity and composition of plants in different saline habitats in inland salt marsh ecosystems. Results showed that plant diversity and species richness in the Carex habitat were significantly higher than the succulent halophyte habitat and the gramineous grass habitat (P < 0.05). Further, species abundance was higher in the succulent halophyte habitat and the Carex habitat than the gramineous grass habitat. Similar results were obtained when considering the abundance of constructive species. No significant differences in the abundance of dominant species and companion species between the gramineous grass habitat and the Carex habitat were found. We concluded that species abundance, species richness, species distribution, and plant diversity together explained the response of plant communities in different habitats to soil salinity, especially Na+ and SO42-. This highlights the importance of soil salinity for the maintenance of plant diversity and structural composition in inland salt marsh ecosystems.
Assuntos
Ecossistema , Áreas Alagadas , Salinidade , Plantas Tolerantes a Sal , SoloRESUMO
Halophytes have been characterized as a potential resource for fiber, food, fodder, and bioactive compounds. Proximate composition, bioactive compounds, and antioxidant activity of five wild dominant halophytes (Arthrocnemummacrostachyum, Halocnemumstrobilaceum, Limoniastrummonopetalum, Limoniastrumpruinosum, and Tamarix nilotica) naturally growing along the Nile Delta coast were assessed. The soil supporting these halophytes was sandy to sand-silty, alkaline, with low organic carbon, and relatively high CaCO3. H. strobilaceum attained the highest moisture content, ash, crude fiber, lipids, and total soluble sugars. L. monopetalum showed the highest content of crude protein (18.00%), while T. nilotica had the highest content of total carbohydrates. The studied halophytes can be ranked according to their nutritive value as follows: H.strobilaceum > L.monopetalum > A.macrostachyum > L.pruinosum > T. nilotica. A. macrostachyum attained the highest amount of Na+, K+, Ca2+, and Mg2+. A. macrostachyum showed a high content of phenolic compounds, while H.strobilaceum was rich in tannins and saponin contents. The MeOH extract of A. macrostachyum and H. strobilaceum exhibited substantial antioxidant activity. The present results showed that the studied halophytes could be considered as candidates for forage production or used as green eco-friendly natural resources for bioactive compounds.
Assuntos
Antioxidantes/química , Antioxidantes/farmacologia , Ecossistema , Compostos Fitoquímicos/química , Compostos Fitoquímicos/farmacologia , Plantas Tolerantes a Sal/química , Geografia , Fenótipo , Plantas Tolerantes a Sal/crescimento & desenvolvimento , Plantas Tolerantes a Sal/metabolismo , Metabolismo Secundário , Solo/químicaRESUMO
The hypotrich Schmidingerothrix elongata spec. nov., discovered in saline (20) soil of the Longfeng Wetland, Daqing, northern China, was studied using live observation and protargol impregnation. It is characterized, inter alia, by colorless cortical granules arranged in short rows, three frontoventral cirral rows with the rightmost extending far posteriorly, and 4-8, usually six macronuclear nodules. Cell division proceeds as in congeners and confirms the lack of dorsal ciliature. In phylogenetic analyses based on SSU rDNA, S. elongata is sister of S. salinarum+Paracladotricha salina. A re-investigation of the type slides of P. salina, type of Paracladotricha, revealed a misobservation in the original description. Since P. salina lacks, like Schmidingerothrix spp., a dorsal ciliature, Paracladotricha becomes a junior, subjective synonym of Schmidingerothrix with S. salina comb. nov. as fourth species. A review of the phylogenetic analyses dealing with Schmidingerothrix shows that its position is variable. However, together with the gonostomatid oral apparatus it can be hypothesized that Schmidingerothrix is a member of the Gonostomatidae or a close relative. A list of genera (14) and species (58) which have - like Schmidingerothrix - a gonostomatid oral apparatus, as well as a key to these genera are provided.