fReprinted from the American Journal ok Botany 9: 471-501. January. 1922.] 



LIBRARY 



NEW YORK 



BOTANICAL 



(jARDfiN 



POLLEN AND POLLEN ENZYMES 



Julia Bayles Paton 



(Received for publication March 28, 192 1) 



I. The Theoretical and Practical Aspects of the Occurrence of 



Pollen Enzymes 



Reasons for Undertaking the Investigation 

 A review of the literature shows very few complete or satisfactory 

 reports of experiments in regard to either the general chemistry or the 

 enzymes of pollen. Our knowledge of the subject seems to be very frag- 

 mentary. It is conspicuous by its omission from the textbooks of botany. 

 Aside from the few references given later, up to the present time no mention 

 of any important work has been found. 



Although it is generally assumed, and is stated in our textbooks, that 

 the pollen tube digests its way through the tissues of the pistil and the 

 ovule, yet there seems to be no experimental evidence as to the exact nature 

 of this enzyme action . Besides this, pollen enzymes must be very important 

 in rendering the food stored in the grain available when the pollen ger- 

 minates, in nourishing the tube during its passage through the style, and 

 in stimulating the development of the embryo and the maturing of the 

 ovary. 



Moreover, pollen anaphylaxis is now regarded as the cause of so-called 

 hay fever and other forms of pollen poisoning. Pollen enzymes may be 

 concerned in these reactions, and the proteolytic enzymes may affect the 

 stability of the pollen-protein solutions used in pollen vaccination. 



In view, therefore, of the apparent meagerness of our knowledge of 

 pollen enzymes and of the possible practical value of any contribution to 

 this subject, it has seemed worth while to study the matter and to present 

 the results. 



The Literature of Pollen Enzymes 

 Few original, systematic experiments have been reported. Erlenmeyer 

 (1874) found amylase, or diastase, in pine pollen. Van Tieghem (1869) 

 reported invertase, or invertin, in the pollen of hyacinth, narcissus, wall- 

 flower, and violet. Czapek (1905, P- 393) quotes Strasburger's statement 

 [The Journal for November (8: 4 2 5"47o) was issued December 19, 1921.] 



471 



