Investigation of urban traffic on the accumulation of heavy elements of lead and cadmium in rosemary (Rosmarinus officinalis L.) and the effect of mycorrhiza (Glomus mossea) symbiosis on it

Nowadays, heavy metal pollution has become a serious environmental problem. To protect the environment, one of the effective and low-cost methods is phytoremediation. Phytoremediation is the use of plants to remove, reduce and stabilize pollutants. In this regard, the use of fungi that symbiosis with plants, can increase the efficiency of phytoremediation, reduce the time required to remove contamination, and develop its application.

This experiment was performed in order to investigate the traffic and symbiosis interaction’s effects on lead and cadmium accumulation in rosemary (Rosmarinus officinalis L.). The experiment donen in a randomized complete block design (RCBD) with three replications and three factors as factorial. The first factor includes mycorrhiza symbiosis (control and inoculation), the second factor was traffic (Control, 120, 300, 600, 950, 1200, 1800, 2400, 3000, 3600, and 4200 cars per hour) and the third factor was the type of pot (Controls and pots where the soil surface is covered except at the place of seedlings) with three replications in 2019-2020 in Shiraz metropolis. In the experiment some properties were investigated such as root weight, soil cadmium, shoot cadmium, root cadmium, stem length, main root length, plant dry weight, root lead, cadmium, and lead transfer factors.

The results of mean comparisons showed that inoculation of plants with mycorrhizal fungi )Glomus mossea (had higher lead content of root tissue than shoots and soil in 4200 cars per hour compared to the control. Symbiosis with mycorrhiza fungi increased root weight and plant dry weight, stem length, and main root length compared to the control by 23.93, 18.97, 0.82 and 30.87% in 4200 car traffic per hour, respectively. The results also showed that the treatment of closed pots and inoculation of mycorrhizal fungi increased the growth parameters and decreased cadmium and lead.

The reduction of cadmium and lead concentrations in the inoculated rosemary with Glomus mosses indicates that Rosmarinus officinalis L. can grow in soils contaminated with cadmium and lead. Also, the symbiosis of mycorrhizae increases th ability of rosemary.