Effects of Copper Toxicity on Seed Germination and Seedling Growth of Brassica napus L. var. oleífera

Objective: The objective of this study was to evaluate the effects of different copper concentrations on the germination and seedling development of canola. Theoretical Framework: Soil contamination by copper can impact the production and quality of canola, making it essential to understand these aspects to ensure sustainable crop management. Method: The experiment was conducted as a randomized complete block design with crossed classification and plots subdivided in time. Each treatment was replicated four times. The main factor (plot) consisted of 4 levels (0, 200, 400, and 800 mg L⁻¹) of copper contamination, and the secondary factor (subplot) consisted of 3 evaluation days (fifth, sixth, and seventh). The seeds corresponding to each treatment were maintained in a germinator at a temperature of 25±2 ºC and a 24-hour photoperiod. Evaluations regarding seed germination, shoot/root length, and the dry weight of seedlings were conducted between the fifth and seventh days after sowing. Analysis of variance was used to evaluate the variables and, when means were significantly different, multiple comparison test (Tukey's HSD) or regression analysis were used, both at a 95% confidence level. Results and Discussion: Different copper concentrations negatively affected the germination rate, root development, shoot growth, and seedling dry mass, leading to an increase in the rate of abnormal seedlings at intermediate copper concentrations. Research Implications: The results raise the importance of understanding the type of agricultural fertilizer being used in an area so as to prevent toxic copper levels to be built up in soils. Originality/Value: Despite a considerable number of studies on the cytotoxic effects and stress mechanisms induced by heavy metals in biological systems, data regarding the effects of this metal on the germination of cultivated plants remain scarce and unclear. There is still a need to clarify many metabolic aspects, justifying the use of canola and copper for furthering the current knowledge on this subject.