Effects of salt stress on water status, photosynthesis and chlorophyll fluorescence of rocket

Abstract

Salinity is a significant environmental factor affecting physiological processes in plants. This study monitors the effect of salt stress induced by the NaCl solution (0 - deionized water; 50, 100, 200, 300 mmol/L) in rocket (Eruca sativa (L.) Mill.) cv. Astro over the course of 50 days. Salt stress significantly affected the monitored parameters. The osmotic potential decreased with increasing NaCl concentrations, while relative water content decrease did not take place until 200 mmol/L NaCl. Compared to the control group, transpiration (E) decreased at the concentration of 50 mmol/L NaCl and stomatal conductance (gs) and net photosynthetic rate (Pn) decreased at 100 mmol/L NaCl. Further increase of salt concentrations did not affect Pn and no significant differences gs, E and substomatal concentration CO2 were measured between the concentrations of 200 and 300 mmol/L NaCl. A decrease of Fv/Fm took place from the concentration of 100 mmol/L NaCl, while differences between 200 and 300 mmol/L NaCl were also not significant. The obtained results therefore prove the tolerance of the E. sativa cv. Astro to salt stress.

Keywords

• rucola
• salinity
• gas exchange, osmotic stress
• net assimilation
• ratio fv/fm
• osmotic adjustment