Ethylene and extraneous material formation in woody tissues

Abstract

Chloroethyl phosphonic acid (CEPA) was administered to the cambial region of Eucalyptus astringens, E. calophylla, E. sieberi and E. sideroxylon. The kino which exuded has been associated with the liberation of ethylene from the CEPA in the sap stream. The kinos from E. astringens and E. calophylla were chemically identical with those obtained naturally from these species. The composition of the polyphenols formed in the sapwood of Rhus after administration of CEPA had a similar chromatographic pattern to that obtained from the heartwood. In both these situations, the induced polyphenols differ from those normally present in the tissues in that the former contain acetate engendered moieties. CEPA produced copious amounts of carbohydrate gum from an apricot branch, and eucalypt sapwood blocks ventilated with ethylene contained a greater proportion of tyloses than the controls. The evidence supports the view that ethylene is an active intermediate in the formation of extraneous components. Under natural conditions, ethylene could arise as a result of injury or physiological stress such as water shortage.