Fig. 3

IAA production of P.indica during growth in CM medium containing the Cd or Phe contamination. Qualitative analysis by the Salkowski-method was performed to identify IAA production under phenanthrene, cadmium and the combined phenanthrene and cadmium treatments. a: After adding the tryptophan, the solution not containing P. indica spores under each treatment does not changed colour in each three repetitions. b: After adding the tryptophan, the solution containing P. indica spores under each treatment changed to pink colour in each three repetitions. c: IAA was determined in culture supernatants by HPLC-MS after 6 weeks containing the Cd, Phe or the combined Cd and Phe contamination medium, respectively. IAA concentrations in CM medium without any contamination were 1.34 + 0.03 μM (n = 3); IAA concentrations in the medium containing Cd were 0.71 + 0.05 μM (n = 3); IAA concentrations in the medium containing Phe were 1.12 + 0.07 μM (n = 3); IAA concentrations in the medium containing the combined Cd and Phe were 0.69 + 0.04 μM (n = 3); respectively. Error bars show standard error. The IAA concentration was significantly reduced in the Cd, Phe and the combined Cd + Phe treatments compared to the control (P. indica) according to the Duncan’s Multiple Range Test (P < 0.05)