Characteristics of Spinach Leaf Injury of Photochemical Oxidants and Mechanisms of Ozone Resistance in Spinach Cultivars (II)

Resistance to Oxidants in Spinach Cultivars

Abstract

Oxidant resistant cultivars of spinach (Spinacia oleracea L.), a major crop in the Tokyo suburbs, were selected and their morphological, physiological, and genetic characteristics were studied in order to reduce oxidant damage to this plant.
The relationship between oxidant resistance in spinach plants and the morphological characteristics, levels of several chemical substances, enzyme activities, and inheritance of these characteristics in spinach leaves was studied in 12 spinach cultivars. Cultivars with leaves that were abundantly notched, or thin, or rich in de-hydroascorbic acid were sensitive to oxidants. Cultivars with leaves that were less abundantly notched, or thick, or round, and leaves with high superoxide dismutase activity were resistant to oxidants.
A sensitive cultivar, Ujo, was reciprocally crossed with a resistant cultivar, Viroflay. The maternal influence was evident, as the oxidant resistance of the first filial generation was midway between that of the parents, and leaf levels of chlorophyll and total sulfhydryl groups also showed inheritance of maternal traits. Ozone resistance in spinach therefore appears to be linked to the chloroplasts, whose role in cytoplasmic inheritance is known.