PRINCIPAL INVESTIGATOR (S ): Stephen W. Gray, and Betty F. Edwards 



EXPERIMENT TITLE/NUMBER : The Effect of Weightlessness on the Growth and 



Orientation of Roots and Shoots of Monocotyledonous 

 Seedlings, P-1020 



PROGRAM/ MISSION : Biosatellite II 



CLASSIFICATION : Plant - Wheat seedlings ( Triticum vuleare ) 



DISCIPLINE(S) : Behavioral science, Cell biology 



OBJECTIVES : To determine alterations in the position of statolith starch 

 grains, the pattern of mitosis and cell elongation, and the biochemistry of 

 the seedlings in a weightless environment, and to determine if weightlessness 

 is adequately simulated by the clinostat. 



PROTOCOL : Seventy-eight wheat seeds weighing 38-39 mg were used in both the 

 flight package and Earth controls. The seeds were surface-sterilized in 0.05? 

 HgCl and soaked for 3 hours in distilled water at 95 F. The seedlings were 

 placed in ploycarbonate stalks containing wet vermiculite. Gas samples were 

 taken and the lids were sealed. All growth took place in darkness. 



EQUIPMENT : Experiment package. 



RESULTS : Inflight germination was unaffected. Coleoptilte height was greater 

 after 58 and 65 hours than control. Statolith starch granules were randomly 

 distributed. Interphase nuclear volume was greater with fewer early prophase 

 cells. Root cells were longer and random orientation of roots and shoots was 

 noted. 



CONCLUSIONS : Short periods of space flight do not disorganize the normal 

 processes of the growing wheat seedling. Only small deviations from normal 

 physiology or behavior were observed, most of them returning to normal after 

 several hours. The Earth bound clinostat may be a tool for predicting some of 

 the responses to weightlessness in suitable organisms. 



PUBLICATIONS : 174, 175, 176, 177, 178, 179, 180, 181, 214, 215 



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