Low pH alleviated salinity stress in ginger seedlings by enhancing light efficiency and equilibrium of mineral elements

Abstract BackgroundSalt stress is one of the abiotic stresses that affect plant growth, and it mainly reduces the biomass of plants by affecting their photosynthesis. However, little is known about the mechanisms by which low pH improves plant growth under salt stress. The effects of low pH on photosynthesis, chlorophyll fluorescence and mineral content in ginger (Zingiber officinale Roscoe) leaves under salt stress were investigated.ResultsIn this study, we found that the plant height and fresh weight, photosynthesis parameter (Pn, Gs, WUE and Tr), pigment concentration, fluorescence (qP, ΦPSII, Fv/Fm), Photosynthetic enzyme (fructose 1,6-diphosphatase (FBPase), ribulose-1,5-bisphosphate carboxylase (Rubisco), fructose 1,6-bisphosphate aldolase (FBA)), sugar metabolism and mineral content were significantly decreased under salt stress, but these parameters were all recovered by low pH. Meanwhile, low pH reduced the content of Na, while enhanced the content of K, Mg, Fe, Ca and Zn in ginger seedling leaves under salt stress. The observation of the ultrastructure of ginger seedlings under salt stress also showed that low pH can alleviate the damage of ginger seedlings to the complete structure and chloroplast.ConclusionsOur results suggested that low pH could enhance salt tolerance by improving photosynthetic efficiency and promoting absorption mineral.