Fig. 1a shows the dry matter yield of T. patula under different
soil B[a]P rates. The addition of B[a]P could facilitate the growth
of plants under the low B[a]P levels (≤10mgkg−1), resulting in an increase at the rate of 8.6–39.0% when compared with the control
group. Especially for the application of 5mg B[a]P kg−1, the statistical
analysis performed to the data showed that the dry biomass
yield of shoots increased significantly (P < 0.05) and obtained the
maximum value of 9.45 g pot−1. However, with an increase in the
concentration of B[a]P in soil, it was observed that there was
inhibitive effects on the growth of plants, showing 18.4% reduction
relative to CK.