384 PLANT PHYSIOLOGY 



QUESTIONS 



1. What is the survival value of sexual reproduction? of asexual? 



2. What is the meaning of homozygous and heterozygous? 



3. Distinguish between sex-determination and sex-regulation. 



4. What is the derivation of parthenocarpy, agamic, ovule, and partheno- 

 genetic? 



5. What are the real sexual organs of a Spermatophyte? 



6. Describe the sexual reproduction of Spirogyra, Rhizopus, and Vaucheria. 



7. What are chimeras? 



8. What is the Manoilov reaction and what is its purpose? 



9. Trace the steps in the "reduction division" when gametes are formed. 



10. According to Yasuda and others (1927) pollen germinates more readily 

 in the stigmatic secretions from another flower than in those from the same 

 flower. Of what value is this? 



11. Male and female plants have been grafted together without influencing 

 the sexual expression of either stock or scion. What may be concluded from 

 this concerning sexuality in plants? 



12. Distinguish between xenia and metaxenia. 



13. What is the sex chromosome situation in man? Does it resemble that 

 in Protentor or that in Populus? 



REFERENCES 



Camp, W. H. — Catalase activity and sex in plants. Am. Jour. Bot., 16:221, 



1929. 

 Daniel, L. — Grafting and evolution. Sci. Am. Mo., 4:115, 1921. 

 Hance, R. T. — The determination of sex. Sci. Mo., 24:25, 1927. 

 Hofman, F. W. — Reciprocal effects upon grafting. Jour. Agric. Res., 34:673, 



1927. 

 Jones, D. F. — Sterility in animals and plants. Sci. Amer. Mo., 2:117, 1920. 

 Knight, R. C. — Vegetative reproduction. Sci. Prog., 21:39, 1926. 

 Priestley, J. H. — Problems of vegetative reproduction. Jour. Roy. Hort. Soc, 



51:1, 1926. 

 Schaffner, J. — Control of sex reversals in the tassel of Indian corn. Bot. 



Gaz., 84:440, 1927. 

 Further experiments in repeated rejuvenations in hemp and their 



bearing on the general problem of sex. Am. Jour. Bot., 15:77, 1928. 

 Stout, A. B. — Types of sterility in plants and their significance in horticulture. 



Mem. Hort. Soc. N. Y., 3:3, 1926. 

 Swingle, W. T. — Metaxenia in the date palm. Jour. Hered., 19:257, 1928. 



