The results showed that the ranges of IAA-production by heavy metal resistant rhizobacteria
were 3.76-157.26 mg/l. Isolate RSH4 produced the highest IAA level (157.26 mg/l) and the second
one was isolate MU1 (123.48 mg/l). Both isolates were assigned cadmium and lead double resistant
PGPR. In general, bacteria that produce IAA as called plant growth-promoting rhizobacteria (PGPR).
Serratia sp. SY5 produced IAA around 38 mg/l (So-Yeon and Cho, 2009). Plants use IAA for cell
division, cell differentiation in plant cells and tissue, and promote root proliferation which enhanced
nutrient uptake into plant (Tsavkelova et al., 2007). These PGPR from screening were cadmium and
lead double resistant PGPR and production of IAA. So, they could be applied for increasing plant
growth under heavy metals polluted condition.