Relationship between the Physical Nature of Mitochondrial Membranes and Chilling Sensitivity in Plants

Abstract

Functional mitochondria were obtained from several plant species of differing sensitivity to injury at chilling temperatures (0-10[degree]C). Mitochondria from chilling-resistant cauliflower buds, turnip roots, and pea seedlings were more flexible, as measured by their greater ability to swell, than were mitochondria from chilling-sensitive tomato fruits, sweet potato roots, bean and corn seedlings. Swelling was measured using light-scattering techniques. Fatty acid analysis of the mitochondria indicated the chilling-resistant species possessed a higher content of unsaturated fatty acids than did mitochondria from sensitive species, and these observations may explain the differences in membrane flexibility. It is suggested that the metabolic injury caused in chilling-sensitive tissues may be due to inability of the relatively inflexible mitochondria to function at low temperatures.