Fitotoxicidade de extratos aquosos de cevada (Hordeum vulgare) sobre germinação e crescimento inicial da buva (Conyza bonariensis)

Abstract

The allopathic effect of cultivated plants represents an important strategy for the management of spontaneous plants, which are among the main limiting factors in agricultural production. Thus, the objective of this work was to evaluate the allopathic effect of barley root extract (Hordeum vulgare) on germination and initial growth of buva seedlings (Conyza bonariensis). The treatments consisted of the concentrations of the aqueous extract of the root of H. vulgare (0, 25, 50, 75 and 100%) obtained by maceration of 250 g of roots up to 900 ml of distilled water. The zero concentration corresponded to the control consisting only of distilled water. The seeds of Conyza bonariensis were placed in Gerbox and incubated in a BOD germination chamber at 25 ° C, remaining for 18 days. The evaluations were started on the 3rd day after sowing and finished with the Germination, Germination Speed Index, Aerial Part Growth (CPA), Root Growth (CR) and Total (CT) evaluations. In the conditions of the experiment, the aqueous extract of the H. vulgaris root did not influence the germination and IVG of the seeds of Conyza bonariensis, except for the CR and CT variables that showed a trend of reduction in the highest concentrations of 75 and 100 % of the aqueous extract of H. vulgaris. In the CPA, there was an increase in the size of the concentrations of 25 to 75%, this stimulatory effect can be explained through the effect known as hormesis.