Saline-alkaline tolerance of hygrophilous plant species during their asexual propagation and continued growth stages

This study determined the saline-alkaline tolerance of seven hygrophilous plant species during their asexual reproduction and continued growth stages. Indicators of asexual reproduction capacities (e.g., number of new buds/seedlings) and growth potential (e.g., total biomass, chlorophyll content index, number and length of new roots), as well as the Na+ and K+ concentrations and Na+/K+ ratios were obtained in tested plant species exposed in five alkaline salt treatments (NaHCO3) ranging from 0.3 to 20 dS/m during the 30 day experiment. The following results were observed: 1) excessive NaHCO3 (especially at a salinity level of EC ≥ 10 dS/m) seriously inhibited the capacity of asexual reproduction and continued growth; 2) the number of new buds/seedlings was significantly (P < 0.05) and positively correlated with the number of new roots of plants, while the number of new buds/seedlings was significantly (P < 0.05) and negatively correlated with the total biomass of plants; and 3) species-specific salt-tolerance strategies were observed, i.e., the entry and compartmentalization of Na+ was controlled, and a low Na+/K+ ratios in different parts of plants was maintained. In general, common reed (Phragmites australis), giant reed (Arundo donax), bulrush (Scirpus validus), and fishscale bamboo (Phyllostachys heteroclada) exhibited better saline-alkaline tolerance during asexual reproduction and continued growth under moderate saline-alkaline conditions. These species are recommended as potential plant species for restoring degraded saline-alkaline wetlands.