## 3 Results  
### Seedling Emergence and Agronomic Parameters of Mungbean Plants  
Our results indicated that PHC contamination substantially reduced the seedling emergence (Figure 1). Furthermore, irrespective of treatments, seedlings started to emerge after four days of sowing in most of the pots with only a few exceptions. Interestingly, the co-addition of biochar and _Enterobacter_ MN17 showed significant improvement in seedling emergence when compared with planted control or their individual application (Figure 1), indicating a significant effect of biochar and strain MN17 application on the emergence of mungbean seedlings. The PHCs also showed significant phytotoxicity to mungbean plants and significantly (\(p\leq 0.05\)) reduced the root and shoot lengths, and fresh and dry biomass (Figures 2 and 3). About 138% and 175% reduction in shoot and root lengths, respectively, were observed in the treatment with PHCs (5000 mg kg\({}^{-1}\)) compared only to the planted control (Figure 2). Moreover, when compared with control (with plants but without diesel or any amendments), 138%, 173%, 163% and 156% reduction in shoot fresh weights, shoot dry weight, root fresh weight and root dry weight, respectively, were observed in the treatment with PHCs only (Figure 3). Furthermore, a decrease in root-to-shoot ratios of mungbean plants in contaminated soil indicated a more negative impact of PHCs on plant roots than shoots (Table 1). Results revealed that PHC phytotoxicity resulted in a significant decrease in the overall growth of mungbean plants. Individual or co-addition of strain MN17 and biochar had positive impacts on the root and shoot lengths, and dry and fresh weights of mungbean plants in PHC contamination (Figures 2 and 3). Remarkably, 33.6% and 41.8% more lengths of the shoots were obtained with the sole application of biochar and strain MN17, respectively, in comparison with the planted control treatment (Figure 2A). Likewise, with the co-addition of biochar and strain MN17, 54% showed higher shoot lengths than that of planted control treatments. Similar observations were made in the case of root length, indicating a nearly 52% increase in root length in their combined application than that of their planted controls (Figure 2B). Additionally, an increase in root-to-shoot ratios of mungbean plants in contaminated soil indicated a more negative impact of PHCs on plant shoots than roots (Table 1). Moreover, in the co-addition of strain MN17 and biochar; 52%, 54%, 55% and 59% higher shoot fresh, shoot dry, root fresh and root dry weights, respectively, were obtained than that of their respective control treatments (Figure 3). Overall, the co-application of _Enterobacter_ sp. MN17 and biochar showed higher growth attributes of mungbean plants under PHC contamination as compared to individual treatment. Figure 1: Effects of _Enterobacter_ sp. MN17 and biochar on seedling emergence of mungbean grown in PHC-contaminated soil. Columns and bars represent means and standard deviation, respectively, of triplicate values. Means with different letters differ significantly according to the least significant difference (LSD) test at \(p\leq 0.05\). (_Control_, Uncontaminated soil with plants; \(P\), Contaminated soil with plants; \(P\)+\(B\), Contaminated soil with plants and biochar; \(P\)+\(E\), Contaminated soil with plants and _Enterobacter_ sp. MN17; \(P\)+\(E\)+\(B\), Contaminated soil with plants, _Enterobacter_ sp. MN17 and biochar). Figure 2: Effects of _Enterobacter_ sp. MN17 and biochar on shoot length (**A**), root length (**B**) of mungbean grown in PHC-contaminated soil. Shoot and root lengths were taken at 90 d after sowing. Columns and bars represent means and standard deviation, respectively, of triplicate values. Means with different letters differ significantly according to the least significant difference (LSD) test at \(p\leq 0.05\). (_Control_, Uncontaminated soil with plants; \(P\), Contaminated soil with plants and biochar; \(P\)+\(E\), Contaminated soil with plants and _Enterobacter_ sp.