Electrical Conductivity of ‘Shamouti’ Orange Peel during Fruit Growth and Postharvest Senescence1

Abstract

Electrical conductivity (EC) measurements were carried out in orange (Citrus sinensis (L.) Osbeck) peel (with stainless steel electrodes penetrating 2 mm deep), during fruit growth and subsequent prolonged storage on shelf. Values at the equator were quite generally lower than at the stem and especially at the stylar ends. A curve showing two maxima, one at a very young fruitlet stage (late May) and the other two months before maturation was found. The decrease in EC toward maturation continued for some time postharvest while the water content of tissues decreased, but was followed by an increase with progressive tissue senescence. This last part of the curve is tentatively explained by an increased role of symplast conductance due to tissue aging.