The purpose of the researches is represented of determination of allopathic effect   realized of Poa pratensis L. on perennial graminaes Festuca rubra L., Dactylis glomerata L. and Lolium perenne L. Given the complexity of the mechanisms by which perennial graminaes interact, we considered in this study the hypothesis of the allelopathic properties at the four perennial graminaes in laboratory conditions, from the point of view of the type of chemical compounds, secondary metabolites. The secondary plant metabolites and their degradation products are important in all agroecosystems, including fodder crops. Many fodder species have indicated that present  an heterotoxicity character, both between fodder species and for weed species.  The symptoms range from the germination capacity, which is the most obvious, to the size and number of organs reduction. The biological material that was studied, is represented by four perennial graminaceae species as: Dactyilis glomerata L., Lolium perenne L., Poa pratensis L. and Festuca rubra L.. The studies were made in the laboratory. The plants were splashed with low alcoholic extracts of the pirolizidinici and ergotic alkaloids respectively, that were obtained from the air part of the plant of the species Poa pratensis L.. The estract have been applied in three different shots, shot of 10 ml/pot, 40 ml/pot and 80 ml/pot. There is a worldwide effort in agriculture, to eliminate the amount of chemical compounds used in the agricultural production technology, by introducing  organic and biological substances. One of the possible solutions is allelopathy, using the chemical interactions between plants. The literature indicates that the active substances of the plant present allelopathic properties.The chemical composition of forage plants is one of the main characteristics in terms of forage quality, the degree of digestibility and consumption depending on the chemical composition. Many plants remove substances with toxic properties, leading to biochemical changes of the environment (habitat). Thus, the alkaloids and glicozizii secreted by the plants have toxic effects on plants. The importance of this paper lies in the fact that the spraying with extracts leads to changes in the chemical composition of plants, changes that vary with the applied dose. Therefore the value of the NFL, NAL, EGV concentrations increases with the increasing of the dose of extract.

perennial graminaes; allelopathy; lolinici acizi; crude protein

Presentation: oral