Mitigation Potential of Vermicompost on Morphophysiological and Mineral Responses of Rocket (Eruca sativa L.) Under High Lead (Pb) Stress
Abstract
Heavy metal pollution, one of the abiotic stress factors, negatively affects agricultural production. Lead (Pb) is one of the most important heavy metals affecting agricultural production. It is important to determine the effect of lead on rocket (Eruca sativa L.), which has a high cultivation potential in agricultural production, and to investigate the effect of vermicompost application in reducing the negative effect of lead stress. This study was carried out in a climate chamber using solid media culture. Rocket (Eruca sativa L.) cv. Bengi was used as plant material. The experiment included four treatments: control (no treatment), vermicompost treatment, 1500 mg kg⁻¹ lead stress, and 1500 mg kg⁻¹ lead stress + vermicompost treatment. The study was terminated after the effects of lead stress were observed. Pb stress increased plant height from 27.42 cm (control) to 25.92 cm, while a greater reduction was observed under Pb stress + vermicompost (24.95 cm). Plant fresh weight declined from 55.23 g in the control to 26.17 g under Pb stress + vermicompost. Plant dry weight decreased from 3.40 g (control) to 1.61 g in the combined treatment. SPAD values increased from 42.10 (control) to 50.52 with vermicompost, while Pb stress resulted in a moderate increase (44.60). Ion leakage increased from 9.76% (control) to 15.33% under Pb stress and reached a maximum of 23.57% in the Pb stress + vermicompost treatment. Leaf Pb content increased from 1.31 ppm (control) to 4.13 ppm under Pb stress, but decreased when vermicompost was applied together with Pb. The results demonstrate that Pb stress disrupts growth, membrane integrity, and nutrient homeostasis in rocket plants. Lead stress severely impairs growth and physiological performance of rocket plants. Vermicompost application alone exerted positive effects on certain physiological traits; however, under Pb stress conditions, it was insufficient to mitigate Pb toxicity and, in some parameters, intensified stress responses.