カヤモノリ, セイヨウハバノリの単子嚢体はイソガワラ類似の藻体である

Abstract

Publisher Summary This chapter discusses the development of zoospores in Ralfsia-like thallus, focusing on the life cycle of the scytosiphonales. Small Ralfsia-like algae commonly grow on smooth pebbles or stones in the intertidal belt at Muroran, from late July to December. They usually mature from October to December and produce unilocular sporangia. The zoospores liberated from them usually develop into two kinds of germlings, slender forms and broader ones, suggesting that the parent plant consists of two different entities. In a study described in the chapter, cultures were started on December 6, 1963, and grown in Schreiber's solution maintained at about 14°C. The broader germlings developed into minute erect leafy fronds within about 3 months following cultivation. The more slender germlings, however, did not produce these erect fronds but crept vigorously on the substratum. In the following year, cultures were started on November 9th and two types of germlings were unialgally cultured in a glass tube containing 10 ml of Provasoli's enriched sea water. By the end of December, in these unialgal cultures, the broader germlings had all developed into erect leafy fronds with plurilocular sporangia.