Prospects • 137 



PROSPECTS 



From time to time throughout this survey suggestions for 

 future work have been briefly made. In an overall view, however, 

 the directions of research in the physiology of flowering are hard 

 to predict with any accuracy, and harder still to recommend with 

 any assurance. The best thing may be simply to ruminate a little 

 on the subject before going back to work. 



One can see that most of the large problems remain. Indeed, 

 one of the major achievements of the research of the past few 

 decades was to delineate these questions in the first place. Among 

 them are the nature or natures of the persistent states induced by 

 photoperiodic or cold treatments; the nature of the flower- 

 controlling substances that move between plant parts or between 

 grafted plants; whether or not endogenous circadian rhythms con- 

 stitute the basic mechanism of photoperiodism; and the relation- 

 ships between juvenility, maturity, and flowering. 



Some questions have been reduced to simpler forms. For 

 example, a question on the role of light and darkness in photo- 

 periodism can be reshaped, at least in part, much more sharply: 

 What is the biochemical role of the red, far-red pigment? Some 

 developmental questions— bolting in rosette plants, for instance- 

 can now be asked, again at least in part, in terms of specific growth 

 substances, the gibberellins. This increased concreteness obviously 

 represents progress; and as long as the answers to such simpler 

 questions are not mistaken for exhaustive explanations of all asso- 

 ciated phenomena, they should increase that progress. 



A major goal— perhaps the only goal— of physiology can be 

 stated as the understanding of growth and development in terms 

 of simpler biochemical systems and their integration. This does not 

 mean that physiology is or ought to be biochemistry; in a sense, 

 the biochemist's job begins where the physiologist's ends, although 

 in practice they necessarily overlap immensely. One can envision 

 the physiologist as taking an organism apart into relatively large 

 portions— speaking in terms of processes— that are then susceptible 

 to biochemical investigation. Unfortunately, the general recogni- 

 tion of the close relationship between physiology and biochemistry 

 has occasionally led to almost meaningless work. For example, an 



