Factors Affecting the Absorption and Retention of Hydrocyanic Acid by Citrus Leaves and Fruits12

Abstract

Green and mature fruits absorbed decreasingly less HCN when preconditioned overnight at 43, 50, 65, and 80[degree] F. Fruits sprayed with a 1% oil spray in the laboratory absorbed less HCN than unsprayed fruits, but similar tests with a 11/2% oil spray in the field showed no appreciable difference. Turgid fruits and leaves absorbed more HCN than nonturgid fruits and leaves under field conditions, but not under laboratory conditions. Fruits from coastal areas absorbed more HCN than similar fruits from inland areas in 1939-40 but less in 1940-41. In both yrs., however, the coastal fruits were more seriously injured than the inland fruits. The amts. of HCN absorbed by fruits and leaves when fumigated under field conditions during the day or at night were approx. the same, but fruits and leaves fumigated during the day were much more severely injured than those fumigated at night. These results indicate that the stomata are not a controlling factor in HCN absorption. Whether or not the fumigated tissues will be injured appears to be governed by the physiol. condition of the tissues more than by the amt. of HCN absorbed.