Fig. 6

Chlorophyll and carotenoid content in control and Tl-treated S. alba leaves. Chlorophyll (a) and carotenoid (b) content measured after extraction with acetone and the calculated chlorophyll a to chlorophyll b (c) and chlorophylls to carotenoids (d) ratios. Additionally the chlorophyll concentration (in relative SPAD values) measured directly from the leaf blade (A, black solid line with full squares). Values are medians from three to six replicates and whiskers show the range of the data; in the case of leaf blade measurements there was at least 20 replicates. Values denoted by the same letter did not differ significantly at p = 0.05. Description of samples abbreviation as given in the legend to Fig. 3