In this study, gibberellic acid 3 (GA3) and uniconazole were applied as the means of improving of cadmium (Cd) polluted site phytoremediation using maize (Zea mays L.). The results showed that GA3 (40 mg/L), and uniconazole (800 mg/L) could increase the biomass, plant height, stem diameter, leaf area, and root parameters of maize plants under Cd stress (0.4 mg/L) by foliar spraying. GA3 (40 mg/L) could increase the SPAD value of maize leaves by 23.45% and the net photosynthetic rate by 645.93%. Both plant regulators could alleviate the oxidative damage of maize and increase the activity of SOD and POD up to 11.44~58.41% and 35.00~99.55%, respectively. The content of MDA and H2O2 could be reduced by GA3 to 31.91% and 24.77%, respectively. GA3 at 40 mg/L could significantly increase the accumulation of Cd ions in the shoots, roots and whole plants of maize by 222.01%, 603.13% and 341.70%, respectively, showing the best effect among tested treatments. It was found that the application of plant growth regulators (PGRs) could increase the biomass and Cd concentration in maize organs, ultimately achieving the purpose of improving the remediation efficiency of Cd by increasing the absolute content of Cd in maize biomass.

The rhizosphere fungal community is essential for determining plant health and improving crop productivity. The fungal community structure and functional roles in the plastic shed soils were explored using high throughput sequencing and FUNGuild in this study. The fungal community structures shifted between the rhizosphere and non-rhizosphere soils. The greatest abundance variation was observed for the rare fungal members with relative abundances <0.1%. In the rhizosphere soil of pepper, the abundance of the genera Purpureocillium, Metacorgyceps, Arthrobotrys, Cephalotheca, and Scedosporium increased significantly, among which, Purpureocillium, Arthrobotrys and Metacorgyceps exhibited biocontrol characteristics. Co-occurrence network analysis revealed different interactions of fungal communities in the rhizosphere and non-rhizosphere soils, both of which were dominated by low abundance members. More positive correlation was identified among the rare members, the fungal pathotroph functions and phthalate acid ester in the rhizosphere soil. This study highlights the important niche of the rare fungal members in soil microbial ecology under plastic shed cultivation.