Variable Growth Responses of Radish, Turnip and Rocket Cultivars to Cadmium and Salinity Treatments

Abstract

T O examine the responses of three vegetable plants to cadmium and salinity stresses, this study was conducted in a greenhouse over two successive years, 2019 and 2020. The chosen plants are radish (Raphanus sativus), rocket (Eruca sativa) and turnip (Brassica rapifera.). The treated plants were exposed separately to cadmium levels of 5, 25 and 50 ppm, and salinity levels of 1000, 1500 and 3000 ppm, through irrigation, in addition to the control treatments (0 ppm Cd or salinity).Cadmium stress on the three vegetable plants caused clear reduction in plant height, root length, biomass, chlorophyll pigments and overall growth parameters over time. Radish, rocket and turnip plants were found to accumulate Cd in their leaves when exposed to different Cd concentrations. Accumulated Cd was increased in leaves tissue with the increase of Cd concentration level. A general decrease in chlorophyll, with the increase of Cd concentration was also detected. The growth of radish, rocket and turnip plants exposed to salinity has been affected and main reductions in plant height and root length with salinity level were observed on the last growth stage (120 days). The results indicated that cadmium treatments had a greatest impact than salinity treatment. Moreover, percentage levels of nitrogen, phosphorus and potassium in leaves of treated different plant species have been affected by cadmium and salinity treatments. In conclusion, radish, rocket and turnip exposed cultivars showed variation in response to these stresses and confirms that species and genotypes crops are differ in their sensitivities to abiotic stresses.