Strontium Uptake and Effects in Hydroponically Cultivated Celery

The artificial radionuclide 90 Sr is the main radionuclide in radioactive environmental pollution. In this study, celery was cultured in a laboratory hydroponics system for 21 days with strontium (Sr) levels of 0 (control), 0.5, 1, 2.5, 5, and 10 mM. The changes in the Sr contents in celery leaves and roots as well as the translocation factor (TF) values (ratio of the Sr concentration in aerial plant parts to that in roots) under different Sr concentrations were studied. Additionally, the effects of Sr stress on the absorption of six nutrients, the chlorophyll content, and the biomass of the celery were investigated. The results showed that the Sr contents in celery leaves and roots increased with the increasing Sr concentration in the hydroponic solution, but the increase of the Sr concentration in roots slowed under the 10 mM Sr treatment. The mean TF values ranged from 0.40 ± 0.01 to 1.12 ± 0.17. With the increase in Sr concentration in the hydroponic medium, the contents of calcium, iron, and potassium in the celery leaves were significantly reduced, and the absorption of calcium, iron, and magnesium by roots was significantly inhibited. Compared with the control, sulfur concentration in celery roots increased significantly under the Sr treatments increasing except the 10 mM Sr treatment. The changes in chlorophyll content were consistent with those of celery biomass, and the values of both these parameters were high under the 5 mM Sr treatment.