Lodo de esgoto tratado no cultivo in vitro de sucupira-preta

Abstract

The high organic matter content of sewage sludge is one of the motivations for their disposal in the environment as a soil conditioner, and at the end of the process, there is a production of one residue denominated the biosolids, wich is rich in organic matter and essential elements to the plants. This study aim to use the biosolids from ETE Paraguaçu (Minas Gerais) as alternative source to in vitro nutrition of sucupira-preta (Bowdichia virgilioides Kunth.), a native woody species from Brazilian Cerrado. Sucupira-preta seeds was sterilized in both 70 % ethanol and hypochlorite of sodium and immersed in 98 % concentrated sulphuric acid for breaking of seed coat dormancy. After 3 rinses in distilled autoclaved water the seeds were inoculated one by each one test tube containing 30 ml of WPM medium and at different concentrations of grounded biosolids. The treatments were divided in four procedures: first control with WPM medium, one with WPM medium amended with increased concentrations of biosolids, other with only increased concentrations of biosolids and the last control medium with only distillated water. The experimental design was completely randomized in a factorial arrangement (2 x 7 with 14 treatments with eight replications), with the presence or absence factor of WPM medium and the biosolids concentration factor (absence; 1,0; 2,0; 4,0; 6,0; 8,0 e 10 g L-¹). Test tubes were maintained in growing room until the 41th day and it was evaluated the number of leaves, aerial part length, leaf area measurements, the number of buds, the number of secondary roots, the length of the main root, the thickness of the stem and the mass of dry matter of the whole plant. The factor with only the biosolids presence was significate influenced the leaf area, number of secondary roots and the number of buds directly. The biosolids presence significantly influences the treatments as the biosolids interacted with WPM medium affecting only the main root length variable. As for the other variables such as the number of leaves, aerial part length, the thickness of the stem and the drier mass, the results showed no significance to those treatments with only biosolids presence. Results demonstrated that the supplementation of medium with the biosolids is possible. The Since the majority of estimated parameters did not have significative differences, it is possible to infer that biosolids has a potential to substitute the nutrients of WPM medium regarding the establishment in vitro of sucupira-preta using seeds as explants. Consequently, it is a safety way for the process besides of the reusing of sludge that result from processes of sewing treatment. Complementary studies searching for the standardization of each components of biosolids will contributed to evaluated the feasibility of this residue use as substrate in plants tissue cultivation.