Probable Future of Auxinology 827 



Now let us get back to differentiation. We know that every cell of 

 the multicellular organism, so far as we can tell today (and this is 

 backed by extensive embryological information) possesses all of the 

 genes which are needed for the assemblage of the whole plant or the 

 whole animal. It is quite obvious, though, that all cells do not use all 

 of the genetic information, do not make all of the enzymes which 

 are needed to make the whole creature. Take a pea plant for example. 

 It has genes in it which tell the cotyledons how to make the reserve 

 protein of pea cotyledons. But this protein does not occur in all parts 

 of the pea plant. The genes for making reserve protein of pea cotyle- 

 dons only do their work when they sit in the cells of a pea cotyledon 

 and do not do their work when they sit in a cell of a root or stem or 

 leaf or flower. Here, then, we return to differentiation. It is quite evi- 

 dent that there is some entity within the nucleus which says to the 

 gene either, "Please be active and make appropriate microsomes which 

 can go out and make the enzyme for which I contain the message," 

 or this entity, whatever it is, says to the gene, "Please be inert and do 

 not send out your message." Differentiation consists of the sequential 

 and properly programmed turning on and off of the genetic informa- 

 tion of the nucleus. Perhaps part of this programming is information 

 contained in the DNA. As one of my students once said, "Perhaps 

 part of the information in the nucleus is information on when to use 

 the information." But I don't know what it is that programs the nu- 

 cleus. Perhaps one of the things that turns the genes off and on in 

 the nucleus is auxin itself. This would indeed be jolly, but I don't 

 believe it. But let's find out what it is that turns genes off and on 

 during the course of development, even if it does not turn out to be 

 auxin. In any case the study of differentiation is clearly enough one 

 of the important tasks of the plant physiology of the future. 



But let us now return to auxinology, the treasury of auxin lore. 

 What does the future hold for our chosen discipline? My principal 

 forecast is that auxinology, as a specific science apart, will ultimately 

 come to an end. Everything will be found out. But auxinology as 

 a part of basic biological lore will be immortal. 



