Kaszab Zoltán (szerk.): A Magyar Természettudományi Múzeum évkönyve 66. (Budapest 1974)

P. Komáromy, Zs.: Studies on the aerophytic Chorhormidium flaccidum (Kütz.) Fott (Ulotrichales)

and have no inclusions, therefore, it is possible that these are gas vacuoles. In the older cells (longer), the vacuoles are bigger than in the younger ones (shorter), thus, mostly the filaments comprising elongate long cells, being of a smaller specific weight, come up onto the surface of the liquid medium (Fig. 2). The diameter of the filaments in the crude cultures deriving from different localities was between 6.3 and 7 fi. In laboratory liquid media (Detmer and Bold inorgatic solution) and in culture medium (Detmer agar and Detmer agar containing 1% glucose) the diameter of the filaments of both formations decreased, and fluctuated between 6.3 and 6.8 /n, but in the majority of cases, they were strictly 6.6 fx. This proves that the diameter is not influenced by the circumstances of the culture but it is an inherent quality. This constant feature may well be used in systematics. The daily examination of the superficial layer and the alga coat (series IV) revealed the presence of a characteristic dynamism. The proportion of the cells •of various length periodically changes in both alga formations. The repeated cell divisions result in a decrease of average cell dimensions (most frequent cell length is 6.6—8.8 (x), in the period of cell elongation, of course, an increase in cell length is observable (most frequent cell length is 11—15.4 fx) (Figs. 3—5.). In the phase subsequent to inoculation, cell elongation is predominant, some 25—30% of the cells in both formations reach a minimum of 15 /x, and become strongly vacuolized. However, the waves of cell division are late in the superficial layer, therefore, in the rhythmic changes of the cell dimensions a phase shift takes place. In case the proportion of the various cells is graphically represented in the function of time, the specific curve is obtained (Figs. 6—7). If cell dimensions are placed into three groups (group I: 2.2—8.8 fx; group II: 11.0—15.4 fx; group III: 16.7—-22.0 fx), the proportion of the groups compared to each other would express the physiological state of the given culture (Table 2). Table. 2. Changes in dimensions of cells in the film layer and in alga coat in the cultures of series IV. observed in the first 10 days, expressed in percent liquid medium Bold Detmer location film layer % alga coat % film layer % alga coat % group I II ill I II III I II III 1 II ill examination in hr. 1 26 73 1 21 73 6 6 82 12 9 66 25 72 4 75 21 9 45 42 6 75 19 6 65 29 96 8 82 10 5 62 32 13 75 12 1 '44 55 120 3 54 43 26 67 7 8 62 30 3 81 16 144 19 74 7 1 72 27 20 75 5 19 61 20 168 3 -5 42 13 80 7 6 58 36 3 81 16 192 33 62 5 9 7S 9 • 1 63 36 20 68 12 216 6 85 9 15 71 14 16 64 20 5 70 25 240 33 62 5 7 61 32 11 71 18 28 63 9 Both in the Detmer and Bold liquid media, the daily changes of cell dimensions may be observed, but owing to the different content and pH of the liquid media, the course of the curves, of course, also diverges from each other. Examination of cultures growing on culture m ed i u m — Cultures growing on culture media were used as controls. From all the