RELATION ENTRE LE DEGRE DE POURRITURE, L’IMPEDANCE DES TISSUS ET LA DENSITE OPTIQUE D’UN EXTRAIT A L’ACETATE D’ETHYLE CHEZ LA RACINE DE LA LUZERNE

Abstract

The impedance of blocks of root tissue of several different rot indices was measured in alfalfa. In addition, optical density readings of ethyl acetate extracts of these blocks were made at 275 and 350 nm. Calculation of the coefficient of correlation between impedance and rot indices 2 to 5 indicates a significant negative correlation. On the other hand, a strong positive correlation was observed between high optical densities and elevated rot indices. While greater precision is achieved with optical density principally for low level of rot, experience indicates that a rot index estimated visually is the most rapid practical method.