Organic free radical levels in seeds and pollen: The effects of hydration and aging |
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Authors: | David A. Priestley Brenda G. Werner A. Carl Leopold Murray B. McBride |
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Affiliation: | Boyce Thompson Institute, Ithaca, NY 14853, U.S.A.;Dept of Agronomy, Cornell Univ., Ithaca, NY 14853, U.S.A. |
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Abstract: | In view of their possible role in oxidative deterioration of seeds and pollen, organic free radicals were measured by electron spin resonance in embryonic axes and cotyledons of soybean [ Glycine max (L.) Merr], embryo and endosperm fractions of corn [ Zea mays L.] and pollen of cattail [ Typha latifolia L.]. A pronounced decline in the radical signal ensued when hydration increased above about 7% (wet weight basis) in both the seed materials and in pollen. Moderate hydration of the soybean axis followed by drying led to a small decrease in organic free radicals compared to untreated material, especially if the desiccation step was performed under nitrogen. In a comparison of soybeans of various ages under normal storage, organic free radical levels in the axis showed little or no increase with age. In marked contrast, over 5 days of accelerated aging at 40°C and near-saturating humidity, organic radical levels approximately doubled in the axis. This pronounced increase in free radical content was not associated with a decrease in the proportion of polyunsaturated fatty acids. The data suggest that hydration of seed and pollen causes a release of free radicals from the trapped state. |
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Keywords: | Electron spin resonance Glycine max maize soybean Typha latifolia Zea mays |
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