Germinação de sementes e crescimento de plântulas de "Zea mays" submetidas a diferentes concentrações de zinco

Abstract

Zinc is naturally present in soils. It is derived from the weathering of the parent material and is also essential for the good development of plants. However, due to the action of man the levels of this metal in the soil have reached toxic concentrations, mainly due to the application of swine manure, used as fertilizer. The aim of this study was to assess the effects of toxic and sub-toxic concentrations of zinc on the germination and growth of corn plants. A trial in randomized subdivided blocks with cross-classification and 3 replicates was performed. The seeds of the cultivar were divided into 4 batches containing 16 replicates of 50 seeds each, and each replicate was sown in Germitex paper pre-moistened with a volume of water corresponding to 2.5 times the paperweight. The water used for soaking the paper of the 4 batches contained different concentrations of zinc sulfate (ZnSO4), so that the final concentrations of zinc were 0.0, 100.0, 200.0 and 400.0 mg/L, generating four different treatments. Paper rolls were kept in incubators at a constant temperature of 25°C, and the evaluations were carried out in three repetitions (on the fifth, sixth and seventh day after sowing) for each treatment. Zinc affected the percentage of germination and size of roots; however it didn’t affect the size of the shoot.