Heavy CHII(I CHIII(I)Y DDI(I) UHII(II)1 DDVII(I KUKI(II) UHI(II) DDII(II) CHII(I)NA DDV(I)
metal (μg/ml) I)K7 6 1   I)1 6 7 1 4 3
Nickel (Ni)
25 + + + + + + + + + +
100 + + + + + + + + + +
400 + + + + + + + + + +
Zinc (Zn)
25 + + + - + + - + - +
100 + + + - - + - + - +
400 + + + - - + - + - +
Cobalt (Co)
25 + + - + - + + + - +
100 + + - - - + + + - +
400 - - - - - - + + - -
Cadmium (Cd)
25 + + + - - - + + - -
100 - + + - - - + + - -
400 - - + - - - + + - -
Lead (Pb)
25 + + + + + + + + + +
100 + + + + + + + + + -
400 + + + - - - - - -  
Copper (Cu)
25 + + + + + + + + +  
100 + + + + + + + + +  
400 - - - - - - - - -  
Chromium (Cr)
25 + - + + - + + - +  
100 + - + + - + - - +  
400 - - + + - + - - -  
Mercury (Hg)
25 - - + - + - + + -  
100 - - - - + - - - -  
400 - - - - + - - - -  
Table 6: Heavy metal tolerance of selected PGPR isolates.