Virgil A. Jolliffe

Changes in Pectic Constituents of Valencia Oranges During Growth and Development

1. The alcohol- and acetone-insoluble solids were recovered periodically from peel and pulp of Valencia oranges. These fractions were analyzed for total pectic substances, using the CO2 method. The results of the two were practically the same. The water-soluble pectins were extracted from the alcohol-insoluble solids and determined colorimetrically by the carbazole method, which analyzes directly for the total anhydrogalacturonic acid units present. A comparison of this method was made with the calcium pectate method, which precipitates the pectic substances down to a limited polymer size and which, because of purity, must be further analyzed by means of CO2 determinations, to determine the uronide content. 2. Seasonal changes in concentrations of pectic substances in peel, pulp, and juice of Valencia oranges were followed by determining the total and the water-soluble pectic substances as anhydrogalacturonic acid during growth and development under normal conditions. After a tremendous initial increase in the total pectic substance in peel and pulp, there is a gradual decrease throughout the remainder of the season. The water-soluble pectins of both peel and pulp also show a gradual decline, but, when observed in relation to the total pectic substances of the corresponding component, the percentage is found to increase in the peel and decline in the pulp before eventually increasing also. The pectic substances found in the juice remain relatively constant throughout.

Metabolism of isopropyl carbanilate (propham) in alfalfa grown in nutrient solution

Abstract Alfalfa plants, Moapa variety, were grown in nutrient solution containing isopropylring-[14C] carbanilate (43.8 μCi/liter propham). After 8 days, 41.2% of the radioactivity initially added to the nutrient culture was recovered; 10.9% of this was from shoots, 3.4% from roots and 26.9% from nutrient medium. Nonextracted residues accounted for 23% of the radioactivity in shoots and 62% of that in roots. The parent herbicide constituted 53 and 38% of the radioactivity extracted from shoots and roots, respectively. The balance of extracted 14C was polar metabolites which were purified and subjected to enzymatic and acid hydrolysis. Four aglycones were isolated, three of which were purified by thin-layer chromatography and characterized by mass spectrometry. The principal aglycones were: isopropyl-2-hydroxycarbanilate, isopropyl-4-hydroxycarbanilate, and 1-hydroxy-2-propylcarbanilate. The fourth aglycone was not identified.