The presence of salts in the leaf exudate improves the photosynthetic performance of a recreto-halophyte, Tamarix chinensis

Abstract

The influence of Tamarix chinensis on its immediate environment and soil health has not been explored, particularly with respect to diurnal and seasonal variations. Thus, the objectives of this study were to: 1. Determine the physiological relevance of excreted salts in improving plant carbon fixation properties, and 2. Investigate the relationship between functional plant traits and environmental variability. A field grown population of T. chinensis was, therefore, studied to characterize its life strategies. Results indicated the presence of excreted salts on leaves enhanced photosynthesis and water use efficiency. Though the extent of nocturnal transpiration was always higher than in the daytime in both washed and unwashed leaves, the unwashed leaves conserved water more efficiently. Precipitation during the period of rapid plant growth alleviated soil salinity and enhanced the availability of essential nutrients. Low temperature and increased soil salinity marked the end of the plant's growth season. Plant’s selective secretion, i.e., increased excretion of toxic ions, was insufficient to restrict ion toxicity resulting in declined plant growth. A consistent soil C:N ratio indicated the maintenance of soil resilience in the presence of test species. Our data suggest that T. chinensis influences species diversity positively by improving soil and atmospheric properties. • The selective secretion of toxic ions from leaf avoided ion toxicity in Tamarix. • Ions on leaf surface supported to capture air water and reflect excessive light. • Removal of salt crystal from leaf disturbed carbon fixation capabilities of leaf. • Net transpiration rate was higher in night. • Soil salinity was decreased during the growing period of Tamarix.