GEORGE S. AVERY, JR. IO9 



ments ran for three weeks, and the Warburg determination for only, 

 three hours, the stimulation range was common to both the growth and 

 the respiration experiments. 



Thus in the past decade it has been found that indoleacetic acid 

 stimulates both respiration and growth in two widely different tissues, 

 one of them carrying a virus disease. In one study where 2,4-D was 

 employed, the general pattern of stimulation closely followed that 

 for indoleacetic acid. Other studies on respiration in response to added 

 hormone (that do not include growth) show that in living tissues certain 

 concentrations of hormone generally stimulate respiration. There is as 

 yet no evidence that hormones occur in tissues in concentrations that 

 would inhibit respiration, and therefore presumably inhibit growth. 



If we are to understand how hormones control metabolism, and 

 ultimately, growth, it is important that we have further studies on the 

 stimulation (and inhibition) of respiration in relation to growth. It 

 is Important, too, that such studies be carried out on tissues capable 

 of giving a growth as well as respiratory response. 



REFERENCES 



1. Berger, J. and Avery, G. S., Jr., Science, 98:454 (1943). 



2. , Am. J. Botany, 30:290 (1943). 



3. , ibid., 30:297 (1943). 



4. ,/^/fl'., 31:11 (1944). 



5. Berger, J., Smith, P., and Avery, G. S., Jr., ibid., 33:601 (1946). 



6. Bonner, ].,]. Gen. Physiol., 17:63 (1933). 



7. , ibid., 20:1 (1936). 



8. , Am. J. Botany, 36:323 (1949). 



9. Brown, J. W., Botan. Gaz., 107:332 (1946). 



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13. Kelly, S. and Avery, G. S., Jr., Am. J. Botany, 36:421 (1949). 



14. Nickell, L. G., Am. J. Botany (in press). 



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16. Smith, F. G., Hamner, C. L., and Carlson, R. F., Plant Physiol., 



22:58 (1947). 



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