INTERNAL DECLINE (ENDOXEROSIS) OF LEMONS IV. THE CARBOHYDRATES IN THE PEEL OF HEALTHY AND ENDOXEROTIC FRUITS

Abstract

Endoxerosis is a physiological disease of lemon fruits, mainly characterized by a loss of water from 'the internal tissues (4, 5). In a very large percentage of instances one of the first visible internal evidences of injury is the presence of gum in the conducting vessels and surrounding tissues, especially in the peel (3). Spoehr (i6), Hooker (II), Rosa (I4), and others have shown that the amounts of pentoses and pentosans in certain plants may be greatly influenced by temperature and by the water content of the tissues. Spoehr concluded that continued low water content in the tissues and high temperature are conducive to the transformation of monosaccharids into pentosans. Since these conditions appear to be most favorable for the production of endoxerosis in lemons, and since gum is often manifestly present in parts of the affected tissues, it seemed desirable to make comparative quantitative determinations of the carbohydrates, especially the pentoses and pentosans, in healthy and endoxerotic lemons.