Influência do extrato de folhas de Sarcophalus joazeiro (Mart.) Hauenschild sobre a germinação de espécies agrícolas.

Abstract

Allelopathy is a biological phenomenon where plants (and microorganisms) produce and release chemical compounds, called allelochemicals, that influence the growth, survival, or reproduction of other nearby species. These effects can be inhibitory (negative) or stimulatory (positive), functioning as a form of chemical competition in the ecosystem. Therefore, the objective of this work was to evaluate the effects of different concentrations of Sarcomphalus joazeiro (Mart.) Hauenschild. extract on the agricultural crops of corn (Zea mays L.), beans (Vigna unguiculata (L.) Walp.), and lettuce (Lactuca sativa L.). For the experiment, juazeiro leaves were collected to prepare the crude extract (100%), using a ratio of 200 g of powder to 1 L of distilled water. From this extract, dilutions were made, obtaining 5 treatments: (T1) distilled water, (T2) 25%, (T3) 50%, (T4) 75% and (T5) 100% of the extract. The assay with L. sativa was carried out in Petri dishes containing a double layer of germitest paper soaked with 6 ml of the extract, using seeds of the Deisy variety. For V. unguiculata and Z. mays, the assays were carried out in rolls of germitest paper hydrated with 28 ml of the solution. All tests were conditioned in a BOD incubator at 25°C, with a 12- hour photoperiod, distributed in 4 replicates of 25 seeds each, and the fungicide Cercobin was applied. The experimental design used was completely randomized, and the variables analyzed were the Percentage of Germination (PG), the Germination Speed Index (IVG), and the Mean Germination Time (TMG). It was observed that, for lettuce, there was a significant difference in the three variables analyzed, with the best results obtained at the lowest dosages. In corn, a difference was only observed for TMG and IVG, with the best values at the lowest concentrations, and no statistical differences were observed in beans.