152 PLANT GROWTH 



plant, in fact, some kinds may be in every living cell. The 

 action of many plant enzymes is similar to the action of ani- 

 mal enzymes, as is the case of the digestion or oxidation of 

 food. Starches, proteins, and fats are common in plants and 

 in animals, and are broken into simpler forms by enzymes in 

 both groups. Many of the vital activities of all organisms 

 are regulated by enzymes but the details of the regulation are 

 not understood. 



Vitamins are probably as essential to plant as to animal 

 life, but plants are able to synthesize them. It is common 

 knowledge that most vitamins for the human diet must come 

 from plants directly or indirectly. Some recent research 

 work suggests that the bacterial life (or its products) of the 

 soil aids the plant in this synthesis. Plants grown on a soil 

 rich in organic matter were higher in vitamin content than 

 those grown on a poorer soil. A supply of stored food in the 

 cells but not light is essential for their production. 



Some plants grown in nutrient solutions have shown a 

 favorable response to added vitamin Bi. Since plants can 

 make vitamins and therefore have them at all times, it has 

 been difficult to study their functions in the plant. Recently 

 certain plants {Camellia, Eucalyptus, and others) have been 

 found, at least under certain conditions, to be able to synthe- 

 size less than the optimum amount of vitamin Bi for their 

 best development. This has been highly popularized and 

 advertised, but it should be kept in mind that most plants 

 in rich soil produce enough for themselves. In such cases 

 soil or plant applications would be of no value. When vita- 

 min Bi is added to test its need in a particular plant, check 

 plants should be left for comparison. 



Bios is a growth substance found in relatively large 

 amounts in yeast and in many other of its relatives, the 

 fungi. When applied to higher plants it stimulates rooting. 

 Bios has been found in the dividing cells of flowering plants. 

 It appears to be important in embryonic cells, rather than 



