Chromium-stress alleviation study using plant growth promoting rhizobacteria for maize ( Zea mays L.)

Abstract

Heavy metal contamination is one of the major environmental threats due to industrialization and urbanization. Among various heavy metals, chromium is of recent concern because it is considered the most hazardous metal pollutant in the environment. Its toxicity alters the process of germination and various other growth parameters ultimately affecting its yield. While maize (Zea mays L.) is one of the most widely cultivated cereal crop being used for fodder, feed and food purposes. It is multipurpose cereal crop and is also used as raw material for different industries. Hence, it is mandatory to come up with effective eco-friendly technique to remediate chromium (Cr) to protect the environment from its toxic impacts. During current research, plant microbe interaction was carried out with Cr resistant strains of Bacillus cereus (3a), Pseudomonas aeruginosa (DS4), Bacillus nitratireducens (TP8), Enterobacter cloacae (A9G) and Pseudomonas sp. (B3) that were selected to observe their beneficial impact on corn (Zea mays L.) growth in presence of Cr stress (150 & 300 µg/mL). Results have indicated that growth and biochemical parameters were enhanced due to bacterial inoculation. In comparison to control, maximum increment in shoot length, number of leaves, root length and fresh weight of inoculated plants was noted up to 46, 115, 76, and 42% respectively. Maximum increment in protein and chlorophyll content of inoculated plants was noted up to 304 and 71% respectively as compared to control. The present study suggests the use of above-mentioned highly chromium resistant bacterial strains to remediate chromium contaminated sites and to improve agricultural production.