Observations on the ultrastructure of flagellar scales in the genus synura (chrysophyceae).

Abstract

1. Flagellar scales have been demonstrated for the first time in Synura echinulata, S. sphagnicola, S. spinosa, S. uvella and Mallomonopsis ouradion and on the smooth flagellum of S. petersenii in addition to those previously described for the long flagellum. In S. petersenii the scales are annular, approximately 100 nm in diameter with a 50 nm hole and in S. sphagnicola linear, 200–300 nm x 60 nm (observations on both flagella); in S. uvella they are semicircular, 60–70 nm x 20 nm, and in Mallomonopsis ouradion oval, 100–120 nm x 60 nm (observations on long flagellum only). Synura echinulata is unique among the species studied in having a mixture of clavate scales, 200 nm x 60 nm, and annular scales 100 nm in diameter on the long flagellum, though only the annular scales have been found on the smooth flagellum. Annular scales have been detected with difficulty on the long flagellum only of S. spinosa. 2. The scales are not arranged in a regular way and their attachment to the flagellar membrane is tenuous, the annular scales being attached by their edges, the elongate scales by one end and the semicircular scales in S. uvella by their convex side. 3. The scales are accumulated, and almost certainly also formed, in a large temporary vesicle similar to the flagellar scale reservoir in Pyramimonas in the Prasinophyceae. 4. This type of flagellar scale is unlike that in any other class of algae and, within the Chrysophyceae, appears to be restricted to genera in the Synuraceae.