Germinação de sementes e crescimento de plântulas de trigo submetidas à diferentes concentrações de cádmio

Abstract

Wheat productivity has been increasing since the mid-1970s. However, for this to be possible, it was necessary to intensify the use of agronomic residues, pesticides and fertilizers, which often contain residues of heavy metals, including cadmium. The objective of this work was to experimentally analyze the effect of different concentrations of cadmium on germination and initial development of wheat seedlings. The experiment was carried out at the Seeds and Grains laboratory at the Federal University of Fronteira Sul, in a split-plot and randomized block scheme, with cross-classification and 4 replications. The wheat seeds were divided into 4 lots of 16 repetitions of 50 seeds each, and each lot was contaminated with a concentration of cadmium (0.0, 25.0, 50.0 and 100.0 mg L™), generating thus four different treatments. The paper coils were kept in a germinator under lighting and a constant temperature of 25°C, and in 4 repetitions of each treatment, randomly removed on the fourth, fifth, sixth and seventh day after the installation of the experiment, the parameters of germination rate were evaluated germination, germination speed, shoot size, root size and dry matter. The different days of evaluation and doses of cadmium used affected the germination potential of the wheat crop. It was also possible to observe a significant difference in the assessment of root growth in all cadmium doses used (25, 50 and 100 mg L), causing necrosis and root atrophy, with the exception of the dose of 0 mg L™. The aerial part was the least affected by the doses used, except for the dose of 100 mg L”, where there was a delay in growth, especially on the seventh and eighth day of evaluation. Regarding dry matter, it was possible to notice a great difference in the dose of 100 mg L'. The germination speed showed a decrease with increasing doses of cadmium. The control (0 mg L™) was the treatment where the best performances were obtained during the evaluations, proving that cadmium, in high concentrations, harms the initial development of wheat.