'^hyte — 9 — Research in Vernalization 



1934 600,000 



1935 2,100,000 



1936 7,000,000 



1937 10,000,000 



More recent data have not been seen ; it is not known to what extent, if 

 at all, Russian farmers are now using the method, or whether any centres 

 for treatment and distribution of vernalized seeds have been operating. 



From an academic point of view, the technique of vernalization, and 

 more particularly the theoretical principles which were evolved on the basis 

 thereof, received a great deal of attention among Russian physiologists. 

 Writing at the request of the author, Maximov (1934) stated that the 

 doubts and contradictions that had arisen would suffice to show that the 

 theory was far trom being completely formulated. "A single investigator or 

 group of investigators around him are, of course, unable to solve all the 

 most difficult problems of the physiology of development," problems which 

 now open to physiologists and others an extensive and fertile field of re- 

 search. 



One of the early interests of Russian investigators in connexion with 

 vernalization was in the possibility of diagnosing whether seeds had had 

 their total treatment required. Methods based upon a staining technique 

 or on the change in iso-electric point were tried, but no satisfactory conclu- 

 sion seems to have been reached. Other investigators wrote on subjects such 

 as the relation of enzymes and hormones to vernalization, the physiological 

 and biochemical characteristics of vernalized as compared with untreated 

 seeds, and of the plants produced from these seeds. The outlook on the 

 breeding of crop plants changed, the emphasis then being placed on the 

 need for preliminary analyses of environmental requirements followed by 

 breeding based upon these specific and varietal characteristics. All these 

 aspects are discussed more fully elsewhere (Whyte, 1946) ; it is at present 

 desirable to refer to two particular aspects of this work in the U.S.S.R., 

 namely, the hormonal interpretation of development with particular refer- 

 ence to the vernalized grain (Cholodny, 1939, see also Cailahjan, 1937), 

 and TuMANOv's work on the relation between developmental phases and 

 winterhardiness (1940). 



A considerable amount of literature has accumulated on the evidence 

 for and against the existence of a hormone which causes flowering in plants. 

 It appears that some such substance does operate, but it has not yet been 

 possible to isolate it, still less to apply it to plants by injection or other 

 methods in order to induce flowering. This hormone is, however, generally 

 associated with the action of light upon leaves, and is assumed to be re- 

 sponsible for transmitting a response taken up by a leaf to the growing 

 point under its control, causing it to exhibit the characteristics either of 

 growth or development. Cholodny has, however, produced an interpreta- 

 tion of the low temperature effect associated with vernalization based on 

 the existence and operation of a hormone. 



The investigations of Schander (1934), Cholodny (1935), Laibach 

 and Meyer (1935) and others have shown that seeds contain reserves of 

 various hormones received from the mother plant and concentrated chiefly 

 in the endosperm or cotyledons. This reserve is believed to come into 



