Abstract

The interactions between plants with rhizosphere and root associated microorganisms have been considered because they are potentially useful in phytoremediation and are used as microbial inoculates (biofertilizers) that give bioprotection to plants against biotic and abiotic stresses. One of the methods safe and effective for introducing bioinoculants is the encapsulation of cells in biodegradable gel matrices like alginate. The aim of this study is to evaluate the effect of three rhizobacteria (Achromobacter sp. strain C1, Pseudomonas sp. strain sp7E and Serratia sp. strain 6), immobilized in alginate beads (bioinoculants) on growth of carpet grass (Axonopus affinis) plantlets against a heavy metal. The results showed the maintenance of the A. affinis plantlets growth against cadmium exposed to immobilized rhizobacteria in alginate beads with a higher cell density under protected micro environment. The results of this study show that the immobilized Achromobacter sp. strain C1 and Serratia sp. strain 6 are suitable bioinoculants because they maintain a higher cell density under protected micro environment as well as the growth of Axonopus affinis plantlets against cadmium.

Key words: Immobilization, plant growth-promoting rhizobacteria, cadmium, Axonopus affinis.