Protective effect of Ocimum basilicum L. essential oil on Lactuca sativa L. treated with cadmium

In recent years, essential oils (EO) are a sustainable and effective alternative to conventional chemical treatments in response to heavy metals in plants. These natural molecules can increase the resilience of plants under stress conditions. In the present work, the ability of EOs from the aerial parts of Ocimum basilicum L. cv 'Prospera' to improve plant response to heavy metals in Lactuca sativa L. grown hydroponically and subjected to Cd stress was investigated. The chemical profile of the essential oil (EO) was analyzed by GC-MS. Essential oil-induced tolerance to different Cd concentrations (36 μM and 72 μM) was studied by analyzing ultrastructural damage by TEM observations, antioxidant response by spectrophotometric analysis, and changes in gene expression by qRT-PCR involved in abiotic stress response. Our results indicated that exogenous EO application of basil helps preserve plastid ultrastructure and ameliorates Cd-induced damage. In addition, there was a reduction in ROS production and beneficial regulation of the activities and molecular expression of antioxidant enzymes. In conclusion, these results clearly indicate the protective ability of basil EO on cytological organization and in modulating the redox state through the antioxidant pathway, reducing Cd-induced oxidative stress.