Germinação de sementes e crescimento de plântulas de Zea mays submetidas à concentrações de cobre

Abstract

Copper is a chemical element which is naturally present in soils. It is originated from the weathering of parent material and is essential for the proper development of plants. However, due to the action of man, the level of this metal in the soil has reached toxic concentrations, mainly because of pig manure usage as a fertilizer. The present work deals with one of the more concentrated metals found in pig manure, copper, which is an element that assists in several processes in the animal body and that is also required by plants, but in low concentrations, as high concentrations cause toxicity to plants. This work aimed at verifying the effects of toxic and sub-toxic concentrations of copper on the germination and growth of corn. A scheme in test plots sub-divided in randomized blocks, with cross-classification and three replicates was used in this work. The kernels of the cultivar were divided into 4 batches with 12 replicates containing 50 kernels each. The kernels were sown in pre-moistened paper towels soaked with a volume of water 2.5 times greater than the weight of the towel. The water used to soak the 4 batches was added with different concentrations of copper sulfate (CuSO4), so that the final concentrations of cooper were 0, 100, 200 and 300 mg/L. The paper rolls were kept in germination chambers at constant temperature (25ºC), and the evaluations were performed, for the three replicates of each treatment, on the fifth, sixth and seventh days after sowing. Copper affected the initial germination rate and root size, however it did not affect the shoot size.