54 FERTILIZATION 



says that 'T. O. Dayton, working in this laboratory, has made 

 chemical tests on pollen of a number of different plants from two 

 species, including Forsythia intermedia var, spectahilis. In none of 

 the pollen from either pin or thrum plants could quercitrin be 

 detected, and all contained rutin. I have tested the effect of boric 

 acid on pollen-tube growth * on incompatible stigmas but with 

 negative results.' Although Lewis suggests a possible explanation 

 of these negative results, the grave doubts which have been ex- 

 pressed about Moewus' Chlamydomonas work (see for example 

 Forster & Wiese, 1954), coupled with these recent findings on 

 Forsythia, must leave all scientists with very uncomfortable 

 feelings. 



Apart from the work of Moewus & Kuhn on the role of flavanone 

 derivatives in plant gametology, claims have been made that 



OCH, 



rhamnosc- 

 glucose — O 



rutinosc 



OH 



hcsperitin 

 Hesperidin 



phosphorylated hesperidin, another flavanone derivative, inhibits 

 fertilization in mammals. Work published on this subject does not 

 make clear at what points in the hesperidin molecule phosphoryla- 

 tion occurs. In 1952 Martin & Bciler reported that oral or intra- 

 peritoneal administration of phosphorylated hesperidin inhibited 

 conception in 44 out of 54 rats. The substance was said to exert 

 its effect on the female and not the male rats. Previously, these 

 two workers had found that phosphorylated hesperidin inhibited 

 the enzyme hyaluronidase and it was this fact which prompted 

 them to investigate its effect on conception in rats. Later in 1952, 

 Sieve claimed that out of 300 married couples he had persuaded 

 to take phosphorylated hesperidin (orally) as a possible contra- 

 ceptive measure, only two had conceived during the experimental 

 period and that these two couples were unreliable. Unlike Martin 



* Moewus (1950) stated that quercitrin and rutin at a dilution of 1:10" were 

 inhibitors of pollen germination in sugar solution and that this inhibition was 

 counteracted by 0.01% boric acid. 



