Ion Concentration Changes in Plants of Varying Tolerance under Saline Environment

Abstract

Core Ideas Two widely cultivated plant species with different salinity tolerance were grown on coastal saline soils.Five levels of water salinity were set for reclamation of saline land using drip irrigation.Ion homeostasis in two plants organs differed with plant salinity tolerance.The threshold of water salinity for two plants was determined. Two widely cultivated plant species (Buddleja alternifolia Maxim. and Weigela florida ‘Red Prince’) with different salinity tolerances were grown in coastal saline soils around Bohai Gulf, China, using drip irrigation at five levels of salinity: 0.8, 3.1, 4.7, 6.3, and 7.8 dS/m. The soil salinity (electrical conductivity of soil saturated extract, ECe), soil pH, plant survival rate, and ion concentration changes in plants were investigated. The results showed that a low soil salinity environment with ECe < 4 dS/m for all saline water treatments was quickly created and maintained especially in the root zone, which confirmed the effectiveness of drip irrigation in salt leaching. Liquid acid added with drip irrigation is proposed in the early reclamation period to avoid alkalization. Ion homeostasis differed with plant salinity tolerance, increasing of K+, Ca2+/Na+, and K+/Na+ in plant tissues and decline of Na+ in the leaf for B. alternifolia were correlated with higher survival rates compared with that of W. florida (Red Prince). Fertilization with K+ and Ca2+ was proposed to reduce the deleterious effects of salinity, especially for salt‐sensitive plants. Irrigation water of salinity up to 7.8 and 3.1 dS/m could be applied in the field to B. alternifolia and cultivar Red Prince, respectively, while maintaining a >75% survival rate.