The present study was carried-out in three different locations in Alexandria city [El-Ebrahimeya zone (traffic area), El-Dekhela zone (industrial area) and Antoniadis Park (control area)] during two successive seasons 2015 and 2016. Homogeneous seedlings of Nerium oleander were planted individually in plastic pots (30 cm diameter) filled with mixture of sand and clay. 90 plants were planted in three locations in Alexandria city (30 plants each zone). Samples were collected during spring and autumn in both seasons.
The obtained results showed the effect of different locations on vegetative growth of Nerium oleander plants. In both seasons, plants planted in Antoniadis Park had the highest leaves, stem and roots parameters in the first and second seasons, respectively. While, plants planted in El-Dekhela had the lowest vegetative growth rate in both seasons. The growth (leaves, stem and root) was also significantly affected by different periods during both seasons. Accordingly, it can be seen that the data were significantly increased gradually in the autumn, while, the lowest growth in the spring.
The results of chemical analysis for plant parts showed the effect of different locations on lead, cadmium and zinc contents in plant parts. In both seasons, plants planted in El-Dekhela had the highest heavy metals content, while, those planted in Antoniadis Park had the lowest lead, cadmium and zinc contents in the first and second seasons, respectively. Chemical analysis of heavy metals content in plant parts was also significantly affected by different periods during both seasons. Accordingly, it can be seen from the data that heavy metals were significantly increased gradually in the spring, while, the lowest heavy metals content (lead, cadmium and zinc) in plant parts was found in autumn in the first and second seasons, respectively.
Transfer factor (TF) indicates the efficiency of Nerium oleander plants to transfer metals from the soil to the plant parts. It can be seen that the transfer factor in the lead, cadmium and zinc content in Nerium oleander plants was increased steadily with different locations. We found that, plants in Antoniadis Park had the highest transfer factor with respect to the heavy metals content, while, those planted in El-Dekhela had the lowest transfer factor in the first season. On the other hand, the highest transfer factor in plant parts, was found in the stem for lead and cadmium, while it was in the leaves for zinc compared with different parts of plant.