Germinação de sementes e crescimento de plântulas de feijoeiro sob diferentes concentrações de cobre

Abstract

Beans are a basic component of the Brazilian diet, constituting their main source of vegetable protein. When cultivation takes place in soils with high concentrations of heavy metals, plant development may be affected. The experiment aimed to evaluate the effects of different doses of copper on the germination and initial development of bean seedlings. The experiment was conducted in the seed and grain laboratory of the Universidade Federal da Fronteira Sul in a subdivided randomized block design with cross classification and 5 repetitions. The seeds were divided into 5 lots of 20 repetitions of 50 seeds and each repetition was sown on paper substrate for seed germination (J. Prolab®) previously moistened with a volume of water corresponding to 2.5 times the weight of the paper. The water used to soak the Germitest® papers was added with different concentrations of copper sulfate (0, 200, 400 and 800 mg L-1 ), generating four different treatments. The rolls containing the seeds were kept in a germinator at a constant temperature of 25ºC with 24h of light. The evaluation of germination percentage, growth of aerial and root parts and speed of germination were performed in 5 repetitions of each treatment, taken randomly on the fourth, fifth, sixth and seventh day after sowing. Copper negatively affected germination in all treatments. Seeds exposed to the 800 mg/L dose showed a high decrease in germination from the first to the last day of analysis. The aerial part, root length and dry mass weight were also negatively affected by copper, which shows that the metal is highly detrimental to the initial development of the bean.