Abstract
When spores of Bacillus megaterium QM B1551 were incubated in acidic buffer containing citric acid, they released such surface metals as Ca, Mg, K, Mn and Fe, and were converted to the hydrogen form (H-spore) which could not germinate with KNO3 plus glucose. The loss of germinability was correlated with the amount of Ca released during the treatment. The germinability of the H-spore was recovered by the subsequent treatment with cations, of which divalent cations, especially Ca ions, were more effective then monovalent cations. These phenomena occurred reversibly when the treatment was repeated. Electron probe x-ray microanalysis of ashed Sr-spores showed that Sr was distributed only in the coat, while Ca was in the coat and the core as that of ashed native spores showed. Ca-spores had an increased germinability to germinants, especially to KNO3. These results suggest that metals, especially Ca, in the coat, which are exchangeable, may play an important role in the initiation of ionic germination.
