NO. 5 COLONIAL FORMATION OF GREEN ALGAE MEIER 3 



Sfichococciis bacillaris, CJilorococcmn iufusionum, Chlorella vulgaris, 

 RapJiidium polyiiiorplmm, and the gonidia of certain lichens. He 

 showed that the formation and quantity of chlorophyll was de- 

 pendent on nitrogenous conditions and carbon sources in the solution. 

 However, different algae vary in this respect. 



Radais (1900) grew Chlorella vulgaris on steamed potato slices and 

 malt extract in light and darkness between 12° and 38° C. (25° C. 

 optimum). The multiplication of the alga was similar in light and 

 in darkness, and when both sets of cultures were dissolved in alcohol 

 and examined spectroscopically, their absorption spectrum at 1/500 

 concentration was found to be 6910 to 6450 A, 6280 to 6040 A, and 

 5920 to 5670 A. A carbon bisulphide solution of the chlorophyll gave 

 the same absorption spectrum but with a shift toward the red and 

 very slight differences in the borders of the bands. Both dark and 

 light cultures gave identical absorption bands. By dilution, the two 

 bands of shorter wave lengths disappeared, but the band 6910 to 

 6450 A was still visible at a concentration of i/iooooo. 



Matruchot and Molliard (1902) reported green cells in Stichococ- 

 cus bacillaris major Naegeli growing in darkness. 



Grintzesco (1903), experimenting with Chlorella vulgaris Beyer- 

 inck, found that too much light — that is, direct sunlight — is unfavor- 

 able and injures the cell membrane. The algae developed well in 

 electric light, but no intensity data are given. The cultures growing 

 in darkness on agar with an addition of 2 percent glucose were a 

 beautiful green and presented a better growth than those in flasks 

 placed in light.. His cultures of Scenedesmus acutits Meyen were 3 

 to 4 times smaller in darkness than in light, but they were green. 



Muenscher (1923) grew a Chlarella in diffuse light and in total 

 absence of light for 105 and 235 days in a nutrient solution to which 

 nitrogen was supplied either as calcium nitrate or ammonium sul- 

 phate. He states that Chlorella can synthesize proteins in total dark- 

 ness when nitrogen is supplied in inorganic combination. 



Colla (1930) found that the chloroplasts of Chlorella were dis- 

 colored when grown on flint stone in a petri dish of Detmer solution 

 for 35 days. He does not mention the presence of glucose in his 

 solution. He then irradiated the alga for 2 hours daily, and the 

 chloroplastids became intensely green the third day. He repeated the 

 experiment with Elodea canadensis which had become etiolated after 

 growing for i month in darkness on dampened cotton. After 2 days 

 of irradiation of 7 hours daily the chlorophyll reappeared in the cells 

 of the plant. He found very little variation in the chlorophyll ab- 

 sorption bands of the normal and the irradiated plants. 



