Potencial alelopático do fumeiro-bravo sobre azevém e trigo

Abstract

The fumeiro-bravo (Solanum mauritianum) is an important tree in the ecological succession processes and is found in the southern region of Brazil. Although allelopathic evidence has already been verified in leaf and fruit extracts of this species, little is known about alcoholic extracts produced from the bark. Thus, this study aimed to evaluate the effect of alcoholic extracts produced from wild hull bark on the germination and initial development of wheat and ryegrass. A preliminary test was carried out, and a test with different concentrations of dry alcoholic extract. For both tests, a completely randomized design (DIC) was used to conduct the experiment, with the preliminary test having 2 treatments, which were the control and crude alcoholic extract, and 8 repetitions. The test with different concentrations of dry alcoholic extract had 5 treatments and 8 repetitions for each culture, where the treatments were different concentrations that were produced from the weighing of dry alcoholic extracts and thus forming the different concentrations, which was 64 g. L-1, 32 g. L-1, 16 g. L-1, 8 g. L-1 and the witness ,. In the preliminary test, crude alcoholic extract of the fumeiro-bravo bark was used, and to perform this it was necessary to collect the barks of fumeiro-bravo and perform the maceration process using 1.5 kg of bark added in a closed container together with 3 , 5 liters of 96% ethyl alcohol for a period of 15 days. After the end of this period, the germination and development test of wheat and ryegrass seedlings was carried out. In the test with different concentrations of dry alcoholic extract, evaporation / concentration of the rest of the crude extract used in the preliminary test was carried out with the aid of the roto-evaporator under an average evaporation temperature of 45ºC. For the elaboration of the treatments, samples of dry extract of 2 (two) grams, 4 (four) grams, 8 (eight) grams and 16 (sixteen) were weighed and placed in beakers and 250 ml of hexane were added and after a week 10 ml of ketone. After diluting the dry extract, it was used to perform germination and initial seedling and ryegrass seedling tests. For the analysis of the results of both tests, the number of normal, abnormal seedlings and non-germinated seeds was counted, and the shoot and root length were measured. Dry and crude alcoholic extract has a negative influence on the germination and initial development of wheat and ryegrass seedlings, and the seeds exposed to dry alcoholic extract generated a percentage of about 90% of abnormal seedlings. Concentrations of dry alcoholic extract of 64 g. L-1, 32 g. L-1 and 16 g. L1 caused the greatest negative allelopathic effects on root length and shoot length. Concentrations of 64 g. L-1 and 32 g. L-1 caused the lowest aerial part length values of wheat and ryegrass seedlings.