Observations on the Germination of Spores of Padina tetrastromatica Hauck

Abstract

The germination of the spores of Padina tetrastromatica Hauck from Mohaballipuram, South of Madras is described in detail for the first time from India for any member of the Dictyotaceae. The tetrasporangium, instead of forming the usual tetraspores, liberates its entire contents which germinate immediately on settling down on the thallus of Padina tetrastromatica , Hauck. The liberated body is spherical in shape and on germination it produces at first a protuberance which on growing for some length as a tubular structure is cut off by a transverse wall from a spherical upper portion. The lower tubular portion, by a few divisions, forms a filamentous structure, the end cell of which produces a sort of a branched haptera on coming into contact with any foreign body. In the upper spherical portion cell divisions occur to result in a somewhat nodular structure. One of the superficial cells of this nodule grows out and by a transverse wall in this, an apical cell in cut off. By the activity of this apical cell new shoots of Padina are developed at first as cylindrical structures. By the growth and division in all cells, later a flattened structure and then a fan shaped thallus is formed characteristic of the Padina plant. In the sequence of divisions and the formation of the rhizoid like structures, Padina tetrastromatica Hauck shows some differences from the other members of the Dictyotaceae reported earlier from abroad.