Abstract
We isolated two chloroplast morphological mutants from a mutant library generated by EMS mutagenesis. One line showed variegated leaf phenotype. Electron microscopic observation indicated that the chloroplasts in the green sector have similar structure to that of wild type, but the plastids in the white sector don't have well developed thylakoid membranes. The abnormalities may be due to a lack of some component that is important in the development or maintenance system of the chloroplast. Another line showed that size and shape of chloroplasts were irregular. This mutant contained expanded chloroplasts up to twice in diameter compared with those of wild type, and tiny chloroplasts in the same cells. The machinery controlling correct division of chloroplasts might be missing. Electron microscopic observation revealed further interesting features. Arrangement and direction of thylakoid membranes were disordered and the stromal area was abnormally expanded. The regulatory mechanism for membrane arrangement might be mutated.
