NaCl and NaHCO₃ mediate tradeoffs in growth, leaf traits, and clonal reproduction of reed (Phragmites communis) under saline-alkali stress

Salinity stress is a serious constraint for crop productivity, and its extent is continuously across the globe. Therefore, it is direly necessary to develop appropriate measures to mitigate the toxic effects of salinity to meet rising food needs. The present study determined the impact of diverse concentrations of neutral salt (NaCl: 0, 200, 400 mM) and alkaline salt (Na2CO3: 0, 25, 50 mM) on the growth status, leaf traits, and clonal component characteristics of reed (Phragmites communis Trin.). The results indicated that increasing the intensity of salt and alkali stress markedly reduced growth (> 30%) and biomass production (> 35%). The impact of alkali stress was more significant as compared to salt stress, and it significantly decreased leaf area and dry matter production and increased the N concentration and N:P ratio. Further, stomata conductance and CO2 concentration showed a decrease under stress conditions. While water use efficiency (WUE) also showed a decreasing trend under saline conditions, it first showed an increasing trend under alkali stress and then a decreasing trend. Further, plant tiller, rhizome, and seeds were markedly reduced by stresses. Moreover, the concentration of Na+ was increased under saline conditions while the concentration of K+ and NO3- showed a marked decrease, Na+/K+ showed a substantial increase. Therefore, salinity and alkaline stress can reduce the growth of reeds by disturbing plant physiological and biochemical functioning and nutrient homeostasis.