The Plant. 107 



abundant in the chlorophyll structures than in other parts of 

 the plant. Loew calls attention to the efficiency of potassium and 

 its compounds in condensing certain aldehydes. He attributes 

 to this element the function of condensation in the formation of 

 carbohydrates and proteins. 



Phosphorus is an essential constituent of the nucleins and nu- 

 cleo-proteins around which the activities of the living plant cell 

 are centered. This element is also a constituent of the active 

 chlorophyll. It is thus seen to be an element with complex and 

 | most important functions. Phosphorous is also a constituent of" 

 lecithin, the chief function of which has been suggested to be that 

 of receiving fatty acids into its molecule and passing them on in 

 soluble form to the protoplasm of the seedling. It would thus 

 serve as a carrier of fats, which furnish energy for. the first 

 growth of the plant. 



Sodium has been shown to be dispensable with many kinds of 

 plants. There is some evidence that sodium chloride or common 

 salt favors the action of diastase and sodium may function in 

 this way in the transformations of carbohydrates. A consider- 

 able amount of work, especially an extended series of plot ex- 

 periments at the Rhode Island Experiment Station with various 

 crops, has afforded evidence that sodium favors economical utiliz- 

 ation of a low potassium supply, particularly when relatively 

 more sodium enters the plant. 



Sulphur is a constituent of all proteins. It forms from 0.4 to 

 4.0 per cent of these compounds. It is a constituent of other or- 

 ganic compounds known as iso-sulpho-cyanates or mustard oils, 

 common to the mustard, turnip and other cruciferous plants. 

 The function of these compounds is not known. 



Iron is essential to green plants and lack of it produces a con- 

 dition of chlorosis, in which the leaves become bleached. While 

 chlorophyll does not contain iron, its action is absolutely depend- 

 ent upon this element, small amounts of the latter being extremely 

 effective. Iron is a constituent of organic compounds in the 

 nuclei of plant cells. 



