A CHLOROPLAST MUTATION IN NICOTIANA-TABACUM-L WHICH HAS TEMPERATURE-SENSITIVE EFFECTS ON GERMINATION AND SEEDLING DEVELOPMENT

Mitochondria and glyoxysomes have well-documented and important roles in the metabolism of germinating seeds. The roles plastids may play during germination are not as well-studied. A plastid mutation in tobacco which retards germination, root hair appearance, hypocotyl emergence and cotyledon emergence, is described. The mutation is temperature-sensitive; at 15 degrees C germination and seedling development are significantly slower than for control plants, while at 24 degrees C germination and seedling development of the mutant and the control are very similar. Prior studies have shown that chlorophyll accumulation and thylakoid development are also defective in this mutant. Plastid functions in seeds and their possible links to chloroplast development are discussed.