A STUDY OF THE INFLUENCE OF DIFFERENT PLANT-SPECIES FROM NATURAL GRASSLANDS ON ENZYMATIC-HYDROLYSIS OF CELL-WALL POLYSACCHARIDES

A study of the influence of different plant species from natural grasslands on enzymatic hydrolysis of cell-wall polysaccharides. A simple, rapid and repetitive method for the estimation of the potential of herbage to inhibit enzymatic activity is described. The enzymatic degradability of the cell walls (the factor determining the organic matter digestibility) was quantified by the phenolic compounds liberated by cellulase action of their ester linkages with cell-wall carbohydrates. Inhibition of this action by some plant compounds solubilised during refluxing in a phosphocitric buffer solution (pH 4.6) was expressed as an index of potential negative action (IANP). This index expresses the action of inhibitory compounds in plant extract on the cellulolytic activity of a fungal enzyme as compared with the activity of this enzyme measured without plant inhibitors. This is useful in the prediction of the potential negative action of plant species on the qualify of the herbage association of which they are a part The determination of IANP in many natural grassland species shows important differences between grass, legumes and other dicotyledonous plants and also within these botanical groups, This index can be useful for the determination of an acceptable proportion of individual plant species in herbages.