PHYSIOLOGICAL AND BIOCHEMICAL CHANGES FOLLOWING INFECTION

The postharvest infection of fruits and other plant organs may induce a number of alterations in their physiological and biochemical processes, or in the host tissue constituents, as a result of host–pathogen interactions. Process changes may include acceleration of ethylene evolution, stimulation of the respiratory enzymes, enhanced pectolytic activity, altered protein synthesis or polyamine-synthesis enzyme activity, and tissue changes may include increased cell-wall soluble pectin, and changed organic acid and sugar contents. The chapter also explains the ethylene synthesis, which is stimulated by mechanical wounding, which occurs while introducing the inoculum into the host. However, comparison between rates of ethylene production elicited by wounds of certain dimensions and those elicited by fungal lesions of similar size indicates that ethylene production in fungus-infected fruits is considerably greater than that in wounded ones.