PRINCIPAL INVESTIGATOR (S ): Cheryl Peltz 



EXPERIMENT TITLE/NUMBER : Cytoplasmic Streaming, ED63 



PROGRAM/MISSION : Skylab 3, 4 



CLASSIFICATION : Plant - Water weed (Elodea) 



DISCIPLINE(S) : Cell biology 



OBJECTIVES : To investigate the effects of null gravity on the cytoplasmic 

 streaming of the Elodea plant. 



PROTOCOL : For each mission, vials containing Elodea sprigs suspended in a 

 nutrient agar solution were prepared for flight and ground control. The 

 flight vials were sealed at 5 psia in an altitude chamber. Preflight tests 

 were conducted to determine the optimum nutrient constituents, and the effect 

 of light, darkness, temperature and vibration on the viability of Elodea . The 

 basic results were that temperatures between 18 C and 34 C, light levels of 15 

 to 25 foot candles, and six days or less of darkness, followed by exposure to 

 light wo" uld have no deleterious effects on Elodea . 



EQUIPMENT : Vials, microscope slides, cover slips, tweezers, microscope, 

 microscope-camera adapter, 16mm motion picture camera. 



RESULTS : The plants flown on Skylab 3 died before photographs could be 

 obtained after 15 days of flight, probably because of 2 unscheduled days of 

 darkness due to experiment scheduling difficulties. The control plants having 

 an identical schedule were also dead. The experiment was reflown on Skylab 4. 

 On the 11th day of that mission, cytoplasmic streaming was observed. By the 

 18th day, these plants had also died. Microscopic photography was not 

 successful due to the removal of a 10-power microscope eye piece and improper 

 exposure of the film. 



CONCLUSIONS : In addition to the problems of excessive dark periods, it may 

 have been difficult for the plant's waste products to diffuse away from the 

 leaf surface in zero gravity. They may have "smothered" in oxygen, unable to 

 obtain the necessary carbon dioxide for photosynthesis. It was suggested that 

 for future experiments with aquatic plants, a water environment be used. 



PUBLICATIONS : 197, 377, 500 



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