Germinação de sementes e crescimento de plântulas de canola submetidas a concentrações de cobre

Abstract

Canola cultivation holds significant importance in the agricultural landscape. However, challenges such as heavy metal contamination (including copper) can impact crop production and quality, and a deep understanding of these aspects is essential to ensure sustainable crop management. The objective of this study was to evaluate the effects of different copper concentrations on canola seed germination and seedling development. The experiment was conducted in the seed and grain laboratory of the Federal University of the Southern Border, Chapecó Campus, and was designed using a split-plot in time scheme within a randomized complete block design, with a crossed classification and 4 replications. The main factor (plot) was metal concentration and was composed of 4 levels (0, 200, 400, and 800 mg L-1 of copper). The secondary factor (subplot) was time and was composed of 3 levels (fifth, sixth, and seventh day). The rolls corresponding to each treatment were divided into batches of 4 rolls, and each batch was placed inside a plastic bag and maintained in a germinator (ELETROlab®, model 202/4) at a constant temperature of 25±2°C and a constant photoperiod of 24 hours. Evaluations were performed on 4 replications of each treatment, randomly removed from the germinator from the fifth to the seventh day after sowing. The evaluation of normal, abnormal, and non-germinated seedlings was performed by quantifying them and converting the data to percentages. Shoot length, root length, and dry weight of the seedlings were also measured. Analysis of variance (F test at 5%) was used to analyze the variables, and comparisons of the means of each replication were made using the Tukey multiple comparison test or regression, both at 95% confidence. The different copper concentrations negatively affected the germination rate of canola seeds, leading to an increase in the rate of abnormal seedlings at intermediate concentrations. The increase in the tested copper concentrations negatively affected the parameters of root development, shoot, and dry mass of the seedlings compared to the control.