508 



RHYTHMS IN PLANTS AND ANIMALS 



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TIME OF DAY 



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Fig. 1. Time memory in bees. The animals were offered food for 7 

 days between 10 and 12 a.m. They continue to search for food at that time 

 of day. (After Beling, 1929.) 



spore discharge (BUhnemann, 1955; Schmidle, 1951; Fig. 3), in 

 bioluminescence (Hastings et al., 1956; Haxo and Sweeney, 1955), 

 in the activity of movements (Figs. 4-6), in the emergence of insects, 

 and in the quantity and quality of light influences on certain processes 



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Fig. 2. Diurnal changes of growth rate in Avena coleoptiles. The 

 seedlings were transferred from red light to darkness at the moment 

 indicated by an arrow. (After Ball and Dyke, 1954.) 



