Germinação de sementes e crescimento de plântulas de algodão (Gossypium hirsutum L.) sob diferentes concetrações de cádmio

Abstract

The cotton crop occupies an expressive position in agribusiness, being highly technical. In this way, various practices are used, such as the massive application of residues, chemical fertilizers and fungicides, these being ways of supplying cadmium and other heavy metals. The present work aimed to analyze the effect of cadmium on the germination and initial development of cotton seedlings in different concentrations of the element. The experiment was conducted at the Seeds and Grains laboratory at the Federal University of Fronteira Sul - Campus Chapecó. A germination test was carried out under a split-plot scheme in time in a randomized block experimental design, with cross classification and 4 replications. The seeds were divided into 4 lots with 16 repetitions, containing 50 seeds sown on Germitest paper substrate previously moistened with a volume of water corresponding to 2.5 times the weight of the paper. The water used for soaking the 4 lots was added with different concentrations of cadmium chloride (CdCl2), so that the final concentrations of cadmium were 0, 25, 50 and 100 mg L-1, generating four different treatments. The variables of germination rate, root size, shoot size and seedling dry mass were evaluated, measured on the fifth, sixth, seventh and eighth days after sowing. The metal interfered in the development of the cotton plant, reducing the germination rate, development of the aerial part and root system and also in the production of dry mass. For the germination rate variable, the higher the dose and the advance of the days, the greater the interference of the metal, reducing germination by 25%. The root size variable was the most responsive to metal interference, with a reduction of up to 84% in the size of the root system.