Fig. 1From: Overlapping toxic effect of long term thallium exposure on white mustard (Sinapis alba L.) photosynthetic activityTolerance of S. alba to different concentrations of Tl. a Tolerance index (IT) of S. alba to Tl during 4 weeks of cultivation. Mean values of IT among groups (control group is 100 % every time) denoted by the same letter did not differ significantly at p = 0.05 (n = 24, for clear picture the SD values were omitted). b total Tl concentration in mineral medium during 4 weeks of cultivation expressed as a % of an initial dose and measured by ICP MSBack to article page