982 BIOLOGICAL EFFECTS OF RADIATION 



treated plants show vascular tissue which is more mature than in control 

 stems of equal age. 



Cells of the growing tip are more sensitive to the rays than those of 

 other regions; the nucleus is more sensitive than the cytoplasm. Many 

 chromosomal irregularities are apparent after irradiation. 



REFERENCES 



1. Altmann, v., D. Rochlin, and E. Gleichgewicht. Uber den entwicklungs- 

 beschleunigenden und entwicklungshemmenden Einfluss der Rontgenstrahlen. 

 Fortsch. Geb. Rontgenstr. 31 : 51-62. 1923. 



2. Ancel, Suzanne. Action de faibles doses de rayons X sur des grains seches. 

 Compt. Rend. Soc. Biol. [Paris] 91: 1435-1436. 1924. {See also (o) Ibid. 93: 

 1669-1670. 1925; (b) 93: 1671-1672. 1925; (c) 96: 986-989. 1927.) 



3. Ancel, Suzanne. Recherche du meilleur test de la radio-reaction des graines 

 des Legumineuses. Bull. Soc. Bot. France 73: 71-73. 1926. {See also (a) 

 Ibid. 72 : 1084-1088. 1926.) 



4. Ancel, Suzanne. De I'influence acc^l^ratrice des raj'ons X sur le d^veloppement 

 des plantes. Arch. Phys. Biol. 5: 106-118. 1926. 



5. Ancel, P., and S. Lallemand. Sur la protection contre Taction des rayons X 

 par une irradiation pr^alable (radiophylaxie). Compt. Rend. Soc. Biol. [Paris] 

 99:1588-1590. 1928. 



6. Arntzen, L., and C. Krebs. Investigations into the biological effect of filtered 

 and unfiltered X-rays as measured on peas. Acta Radiologica 4: 5-31. 1925. 



7. Bersa, Egon. Strahlenbiologische Untersuchungen. I. Sitzungsber. Akad. 

 Wiss. Wien Math.-Natw. Kl. Abt. 1. 135: 425-451. 1926. {See also (a) Paper 

 II. Ibid. 136: 383-402. 1927; (6) Paper III. Ibid. 136: 403-418. 1927.) 



8. Capizzaro, N. Sobre la acci6n biol6gica de las radiaciones Roentgen. Influencia 

 de los rayons-X producidos por corrientes de alta tension y milliamperaje elevado 

 sobre la germinaci6n de las semillas. Bol. Inst. Med. Exp., Buenos Aires 2 : 

 922-928. 1926. 



9. Cattell, Ware. The effect of X-rays on the growth of wheat seedlings. Science 

 73:531-533. 1931. 



10. Geller, F. C. Die Wirkung der Rontgenstrahlen auf jugendliche Organismen. 

 Klin. Wochensch. 3: 561-566. 1924. 



11. Glocker, R., E. Hayer, and O. JiJngling. tJber die biologische Wirkung 

 verschiedener Rontgenstrahlenqualitaten bei Dosierung in R Einheiten. Strah- 

 lentherapie 32 : 1-38. 1929. 



12. GooDSPEED, T. H. The effect of X-rays and radium on species of the genus 

 Nicotiana. Jour. Hered. 20: 243-260. 1929. 



13. GooDSPEED, T. H. Cytological and other features of variant plants produced 

 from X-raj^ed sex cells of Nicotiana tal)acum. Botan. Gaz. 87: 563-582. 1929. 



14. GooDSPEED, T. H., and A. R. Olson. Genetic and other effects of X-ray and 

 radium treatment of seeds, growing points, and sex cells of Nicotiana species. 

 Amer. Jour. Bot. 16: 622. 1928. 



15. Halberstaedter, L., and A. Simons. Zum Problem der Reizwirkung der 

 Rontgenstrahlen. Biologische Ergebnisse aus Versuchen an Pflanzen. Fortsch. 

 Geb. Rontgenstr. 28: 499-611. 1922. 



16. Horlacher, W. R., and D. T. Killough. Radiation-induced variation in 

 cotton. Somatic changes induced in Gossypium hirsutum by X-raying seeds. 

 Jour. Hered. 22: 253-262. 1931. 



17. IvEN, Hubert. Neuere Untersuchungen iiber die Wirkung der Rontgenstrahlen 

 auf Pflanzen. Strahlentherapie 19: 413-461. 1925. 



