Studies on the germination of propagules of Isopterygium (Musci)

Abstract

  Propagules of three species of Isopterygium: I. elegans (Brid.) Lindb. from Sweden, I. pohliaecarpum (Sull. et Lesq.) Jaeg. from Japan, and I. maebarae Sak. from Japan were cultured on agar which contains Benecke's solution at 25° ± 1℃. In all three species, propagules were germinated from both ends and formed filamentous secondary protonemata. However, some old, blackish brown propagules of I. maebarae germinated only from the stalk cells which have much thinner cell walls than those of the main bodies. Leafy gametophytes were developed from the secondary protonemata or directly from the upper end of propagules in all three species. Secondary propagules were formed abundantly on the protonemata of I. pohliaecarpum, while no secondary propagules were found in I. elegans during the seven months culture period in the same culture conditions. In I. maebarae, the secondary propagules were formed on the protonemata as well as on young leafy shoots developed on the secondary protonemata. Some other works on similar secondary gemmae formation were reviewed and discussed.